Initial delivery of SAX XML Writer/Parser framework for XStream replacement. The metadata and artifact repository writers/parsers are included, but not currently used.

38 files changed, 3058 insertions, 102 deletions

diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/.classpath b/bundles/org.eclipse.equinox.p2.artifact.repository/.classpath
index 7cdeb7319..ce7393340 100644
--- a/bundles/org.eclipse.equinox.p2.artifact.repository/.classpath
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/.classpath
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
 	<classpathentry kind="src" path="src"/>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/CDC-1.1%Foundation-1.1"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/J2SE-1.4"/>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="output" path="bin"/>
 </classpath>
diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/META-INF/MANIFEST.MF b/bundles/org.eclipse.equinox.p2.artifact.repository/META-INF/MANIFEST.MF
index df592a14e..daa676b87 100644
--- a/bundles/org.eclipse.equinox.p2.artifact.repository/META-INF/MANIFEST.MF
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/META-INF/MANIFEST.MF
@@ -10,8 +10,10 @@ Export-Package: org.eclipse.equinox.internal.p2.artifact.repository;x-friends:="
  org.eclipse.equinox.p2.artifact.repository.processing,
  org.eclipse.equinox.spi.p2.artifact.repository
 Import-Package: com.thoughtworks.xstream,
- org.eclipse.core.runtime.preferences,
+ javax.xml.parsers,
+ org.eclipse.core.runtime.preferences;resolution:=optional,
  org.eclipse.equinox.internal.p2.jarprocessor;resolution:=optional,
+ org.eclipse.equinox.internal.p2.metadata,
  org.eclipse.equinox.p2.core.helpers,
  org.eclipse.equinox.p2.core.location,
  org.eclipse.equinox.p2.core.repository,
@@ -19,9 +21,12 @@ Import-Package: com.thoughtworks.xstream,
  org.eclipse.equinox.p2.metadata,
  org.eclipse.equinox.spi.p2.core.repository,
  org.eclipse.osgi.internal.provisional.verifier,
+ org.eclipse.osgi.service.resolver;version="1.1.0",
+ org.eclipse.osgi.util;version="1.1.0",
  org.osgi.framework;version="1.3.0",
  org.osgi.service.prefs;version="1.1.0",
- org.osgi.util.tracker;version="1.3.0"
+ org.osgi.util.tracker;version="1.3.0",
+ org.xml.sax;resolution:=optional
 Bundle-Activator: org.eclipse.equinox.internal.p2.artifact.repository.Activator
 Eclipse-LazyStart: true
 Bundle-RequiredExecutionEnvironment: CDC-1.1/Foundation-1.1,
diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/ArtifactRepositoryIO.java b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/ArtifactRepositoryIO.java
index 0c2208f40..e51af1740 100644
--- a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/ArtifactRepositoryIO.java
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/ArtifactRepositoryIO.java
@@ -12,24 +12,95 @@ package org.eclipse.equinox.internal.p2.artifact.repository;
 
 import com.thoughtworks.xstream.XStream;
 import java.io.*;
+import java.util.*;
+import javax.xml.parsers.ParserConfigurationException;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.equinox.internal.p2.metadata.ArtifactKey;
+import org.eclipse.equinox.p2.artifact.repository.ArtifactDescriptor;
 import org.eclipse.equinox.p2.artifact.repository.IArtifactRepository;
+import org.eclipse.equinox.p2.artifact.repository.processing.ProcessingStepDescriptor;
+import org.eclipse.equinox.p2.core.helpers.*;
 import org.eclipse.equinox.p2.core.repository.RepositoryCreationException;
+import org.eclipse.equinox.p2.metadata.IArtifactKey;
+import org.eclipse.osgi.service.resolver.VersionRange;
+import org.eclipse.osgi.util.NLS;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.Version;
+import org.xml.sax.*;
 
 /**
- * This class reads and writes artifact repository 
- * (eg. table of contents files);
+ * This class reads and writes artifact repository metadata
+ * (e.g. table of contents files);
  * 
  * This class is not used for reading or writing the actual artifacts.
  * 
  * The implementation currently uses XStream.
  */
+
+// TODO: this class should be renamed to SimpleArtifactRepositoryIO
+//		 when the use of XStream is eliminated.
+// TODO: Should a registration/factory mechanism be supported
+//		 for getting a repository reader/writer given a repository type
 class ArtifactRepositoryIO {
 
 	/**
+	 * Writes the given artifact repository to the stream.
+	 * This method performs buffering, and closes the stream when finished.
+	 * 
+	 * Persistence implementation using XStream
+	 * @deprecated
+	 */
+	public static void write(SimpleArtifactRepository repository, OutputStream output) {
+		XStream stream = new XStream();
+		OutputStream bufferedOutput = null;
+		try {
+			try {
+				bufferedOutput = new BufferedOutputStream(output);
+				stream.toXML(repository, bufferedOutput);
+			} finally {
+				if (bufferedOutput != null) {
+					bufferedOutput.close();
+				}
+			}
+		} catch (FileNotFoundException e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		} catch (IOException e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+	}
+
+	/**
+	 * Write the given SimpleArtifactRrepository to the given stream.
+	 * This method closes the stream when finished.
+	 */
+	public void writeNew(SimpleArtifactRepository repository, OutputStream output) {
+		OutputStream bufferedOutput = null;
+		try {
+			try {
+				bufferedOutput = new BufferedOutputStream(output);
+				Writer repositoryWriter = new Writer(bufferedOutput);
+				repositoryWriter.write(repository);
+			} finally {
+				if (bufferedOutput != null) {
+					bufferedOutput.close();
+				}
+			}
+		} catch (IOException ioe) {
+			// TODO shouldn't this throw a core exception?
+			ioe.printStackTrace();
+		}
+	}
+
+	/**
 	 * Reads the artifact repository from the given stream,
 	 * and returns the contained array of abstract artifact repositories.
 	 * 
 	 * This method performs buffering, and closes the stream when finished.
+	 * 
+	 * Persistence implementation using XStream
+	 * @deprecated
 	 */
 	public static IArtifactRepository read(InputStream input) throws RepositoryCreationException {
 		XStream stream = new XStream();
@@ -48,27 +119,439 @@ class ArtifactRepositoryIO {
 	}
 
 	/**
-	 * Writes the given artifact repository to the stream.
-	 * This method performs buffering, and closes the stream when finished.
+	 * Construct a SimpleArtifactRepository by reading from the given stream.
+	 * This method closes the stream when finished.
 	 */
-	public static void write(IArtifactRepository repository, OutputStream output) {
-		XStream stream = new XStream();
-		OutputStream bufferedOutput = null;
+	public SimpleArtifactRepository readNew(InputStream input) throws RepositoryCreationException {
+		BufferedInputStream bufferedInput = null;
 		try {
 			try {
-				bufferedOutput = new BufferedOutputStream(output);
-				stream.toXML(repository, bufferedOutput);
+				bufferedInput = new BufferedInputStream(input);
+				Parser repositoryParser = new Parser(Activator.getContext(), Activator.ID);
+				repositoryParser.parse(input);
+				if (!repositoryParser.isValidXML()) {
+					throw new RepositoryCreationException(new CoreException(repositoryParser.getStatus()));
+				}
+				return repositoryParser.getRepository();
 			} finally {
-				if (bufferedOutput != null) {
-					bufferedOutput.close();
+				if (bufferedInput != null)
+					bufferedInput.close();
+			}
+		} catch (IOException ioe) {
+			throw new RepositoryCreationException(ioe);
+		}
+	}
+
+	private interface XMLConstants extends org.eclipse.equinox.p2.core.helpers.XMLConstants {
+
+		// Constants defining the structure of the XML for a SimpleArtifactRepository
+
+		// A format version number for simple artifact repository XML.
+		public static final String XML_VERSION = "0.0.1"; //$NON-NLS-1$
+		public static final Version CURRENT_VERSION = new Version(XML_VERSION);
+		public static final VersionRange XML_TOLERANCE = new VersionRange(CURRENT_VERSION, true, CURRENT_VERSION, true);
+
+		// Constants for processing instructions
+		public static final String PI_REPOSITORY_TARGET = "artifactRepository"; //$NON-NLS-1$
+		public static XMLWriter.ProcessingInstruction[] PI_DEFAULTS = new XMLWriter.ProcessingInstruction[] {XMLWriter.ProcessingInstruction.makeClassVersionInstruction(PI_REPOSITORY_TARGET, SimpleArtifactRepository.class, CURRENT_VERSION)};
+
+		// Constants for artifact repository elements
+		public static final String REPOSITORY_ELEMENT = "repository"; //$NON-NLS-1$
+		public static final String MAPPING_RULES_ELEMENT = "mappings"; //$NON-NLS-1$
+		public static final String MAPPING_RULE_ELEMENT = "rule"; //$NON-NLS-1$
+		public static final String ARTIFACTS_ELEMENT = "artifacts"; //$NON-NLS-1$
+		public static final String ARTIFACT_ELEMENT = "artifact"; //$NON-NLS-1$
+		public static final String PROCESSING_STEPS_ELEMENT = "processing"; //$NON-NLS-1$
+		public static final String PROCESSING_STEP_ELEMENT = "step"; //$NON-NLS-1$
+
+		// Constants for attributes of artifact repository elements
+		public static final String VERIFY_SIGNATURE_ATTRIBUTE = "verify"; //$NON-NLS-1$
+
+		public static final String MAPPING_RULE_FILTER_ATTRIBUTE = "filter"; //$NON-NLS-1$
+		public static final String MAPPING_RULE_OUTPUT_ATTRIBUTE = "output"; //$NON-NLS-1$
+
+		public static final String ARTIFACT_NAMESPACE_ATTRIBUTE = NAMESPACE_ATTRIBUTE;
+		public static final String ARTIFACT_CLASSIFIER_ATTRIBUTE = CLASSIFIER_ATTRIBUTE;
+
+		public static final String STEP_DATA_ATTRIBUTE = "data"; //$NON-NLS-1$
+		public static final String STEP_REQUIRED_ATTRIBUTE = "required"; //$NON-NLS-1$
+	}
+
+	// XML writer for a SimpleArtifactRepository
+	protected class Writer extends XMLWriter implements XMLConstants {
+
+		public Writer(OutputStream output) throws IOException {
+			super(output, PI_DEFAULTS);
+		}
+
+		/**
+		 * Write the given artifact repository to the output stream.
+		 */
+		public void write(SimpleArtifactRepository repository) {
+			start(REPOSITORY_ELEMENT);
+			attribute(NAME_ATTRIBUTE, repository.getName());
+			attribute(TYPE_ATTRIBUTE, repository.getType());
+			attribute(VERSION_ATTRIBUTE, repository.getVersion());
+			attributeOptional(PROVIDER_ATTRIBUTE, repository.getProvider());
+			attributeOptional(DESCRIPTION_ATTRIBUTE, repository.getDescription()); // TODO: could be cdata?
+			attribute(VERIFY_SIGNATURE_ATTRIBUTE, repository.getSignatureVerification(), false);
+
+			writeProperties(repository.getProperties());
+			writeMappingRules(repository.getRules());
+			writeArtifacts(repository.getDescriptors());
+
+			end(REPOSITORY_ELEMENT);
+			flush();
+		}
+
+		private void writeMappingRules(String[][] rules) {
+			if (rules.length > 0) {
+				start(MAPPING_RULES_ELEMENT);
+				attribute(COLLECTION_SIZE_ATTRIBUTE, rules.length);
+				for (int i = 0; i < rules.length; i++) {
+					start(MAPPING_RULE_ELEMENT);
+					attribute(MAPPING_RULE_FILTER_ATTRIBUTE, rules[i][0]);
+					attribute(MAPPING_RULE_OUTPUT_ATTRIBUTE, rules[i][1]);
+					end(MAPPING_RULE_ELEMENT);
+				}
+				end(MAPPING_RULES_ELEMENT);
+			}
+		}
+
+		private void writeArtifacts(Set artifactDescriptors) {
+			start(ARTIFACTS_ELEMENT);
+			attribute(COLLECTION_SIZE_ATTRIBUTE, artifactDescriptors.size());
+			for (Iterator iter = artifactDescriptors.iterator(); iter.hasNext();) {
+				ArtifactDescriptor descriptor = (ArtifactDescriptor) iter.next();
+				IArtifactKey key = descriptor.getArtifactKey();
+				start(ARTIFACT_ELEMENT);
+				attribute(ARTIFACT_NAMESPACE_ATTRIBUTE, key.getNamespace());
+				attribute(ARTIFACT_CLASSIFIER_ATTRIBUTE, key.getClassifier());
+				attribute(ID_ATTRIBUTE, key.getId());
+				attribute(VERSION_ATTRIBUTE, key.getVersion());
+				writeProcessingSteps(descriptor.getProcessingSteps());
+				writeProperties(descriptor.getProperties());
+				end(ARTIFACT_ELEMENT);
+			}
+			end(ARTIFACTS_ELEMENT);
+		}
+
+		private void writeProcessingSteps(ProcessingStepDescriptor[] processingSteps) {
+			if (processingSteps.length > 0) {
+				start(PROCESSING_STEPS_ELEMENT);
+				attribute(COLLECTION_SIZE_ATTRIBUTE, processingSteps.length);
+				for (int i = 0; i < processingSteps.length; i++) {
+					start(PROCESSING_STEP_ELEMENT);
+					attribute(ID_ATTRIBUTE, processingSteps[i].getProcessorId());
+					attribute(STEP_DATA_ATTRIBUTE, processingSteps[i].getData());
+					attribute(STEP_REQUIRED_ATTRIBUTE, processingSteps[i].isRequired());
+					end(PROCESSING_STEP_ELEMENT);
+				}
+				end(PROCESSING_STEPS_ELEMENT);
+			}
+		}
+	}
+
+	/*
+	 * Parser for the contents of a SimpleArtifactRepository,
+	 * as written by the Writer class.
+	 */
+	private class Parser extends XMLParser implements XMLConstants {
+
+		private SimpleArtifactRepository theRepository = null;
+
+		public Parser(BundleContext context, String bundleId) {
+			super(context, bundleId);
+		}
+
+		public void parse(File file) throws IOException {
+			parse(new FileInputStream(file));
+		}
+
+		public synchronized void parse(InputStream stream) throws IOException {
+			this.status = null;
+			try {
+				// TODO: currently not caching the parser since we make no assumptions
+				//		 or restrictions on concurrent parsing
+				getParser();
+				RepositoryHandler repositoryHandler = new RepositoryHandler();
+				xmlReader.setContentHandler(new RepositoryDocHandler(REPOSITORY_ELEMENT, repositoryHandler));
+				xmlReader.parse(new InputSource(stream));
+				if (isValidXML()) {
+					theRepository = repositoryHandler.getRepository();
+				}
+			} catch (SAXException e) {
+				throw new IOException(e.getMessage());
+			} catch (ParserConfigurationException e) {
+				throw new IOException(e.getMessage());
+			} finally {
+				stream.close();
+			}
+		}
+
+		public SimpleArtifactRepository getRepository() {
+			return theRepository;
+		}
+
+		protected Object getRootObject() {
+			return theRepository;
+		}
+
+		private final class RepositoryDocHandler extends DocHandler {
+
+			public RepositoryDocHandler(String rootName, RootHandler rootHandler) {
+				super(rootName, rootHandler);
+			}
+
+			public void ProcessingInstruction(String target, String data) throws SAXException {
+				if (PI_REPOSITORY_TARGET.equalsIgnoreCase(target)) {
+					// TODO: should the root handler be constructed based on class
+					// 		 via an extension registry mechanism?
+					// String clazz = extractPIClass(data);
+					// and
+					// TODO: version tolerance by extension
+					Version repositoryVersion = extractPIVersion(target, data);
+					if (!XML_TOLERANCE.isIncluded(repositoryVersion)) {
+						throw new SAXException(NLS.bind(Messages.SimpleArtifactRepositoryIO_Parser_Has_Incompatible_Version, repositoryVersion, XML_TOLERANCE));
+					}
+				}
+			}
+
+		}
+
+		private final class RepositoryHandler extends RootHandler {
+
+			private final String[] required = new String[] {NAME_ATTRIBUTE, TYPE_ATTRIBUTE, VERSION_ATTRIBUTE};
+			private final String[] optional = new String[] {DESCRIPTION_ATTRIBUTE, PROVIDER_ATTRIBUTE, VERIFY_SIGNATURE_ATTRIBUTE};
+
+			private String[] attrValues = new String[required.length + optional.length];
+
+			private MappingRulesHandler mappingRulesHandler = null;
+			private PropertiesHandler propertiesHandler = null;
+			private ArtifactsHandler artifactsHandler = null;
+
+			private SimpleArtifactRepository repository = null;
+
+			public RepositoryHandler() {
+				super();
+			}
+
+			public SimpleArtifactRepository getRepository() {
+				return repository;
+			}
+
+			protected void handleRootAttributes(Attributes attributes) {
+				attrValues = parseAttributes(attributes, required, optional);
+				attrValues[2] = checkVersion(REPOSITORY_ELEMENT, VERSION_ATTRIBUTE, attrValues[2]).toString();
+				attrValues[5] = checkBoolean(REPOSITORY_ELEMENT, VERIFY_SIGNATURE_ATTRIBUTE, attrValues[5], false).toString();
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (MAPPING_RULES_ELEMENT.equalsIgnoreCase(name)) {
+					if (mappingRulesHandler == null) {
+						mappingRulesHandler = new MappingRulesHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (ARTIFACTS_ELEMENT.equalsIgnoreCase(name)) {
+					if (artifactsHandler == null) {
+						artifactsHandler = new ArtifactsHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (PROPERTIES_ELEMENT.equalsIgnoreCase(name)) {
+					if (propertiesHandler == null) {
+						propertiesHandler = new PropertiesHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+
+			protected void finished() {
+				if (isValidXML()) {
+					String[][] mappingRules = (mappingRulesHandler == null ? new String[0][0] //
+							: mappingRulesHandler.getMappingRules());
+					OrderedProperties properties = (propertiesHandler == null ? new OrderedProperties(0) //
+							: propertiesHandler.getProperties());
+					Set artifacts = (artifactsHandler == null ? new HashSet(0) //
+							: artifactsHandler.getArtifacts());
+					boolean verifySignature = (attrValues[5] == null ? false //
+							: new Boolean(attrValues[5]).booleanValue());
+					repository = new SimpleArtifactRepository(attrValues[0], attrValues[1], attrValues[2], attrValues[3], //
+							attrValues[4], verifySignature, artifacts, mappingRules, properties);
 				}
 			}
-		} catch (FileNotFoundException e) {
-			// TODO Auto-generated catch block
-			e.printStackTrace();
-		} catch (IOException e) {
-			// TODO Auto-generated catch block
-			e.printStackTrace();
 		}
+
+		protected class MappingRulesHandler extends AbstractHandler {
+
+			private List mappingRules;
+
+			public MappingRulesHandler(AbstractHandler parentHandler, Attributes attributes) {
+				super(parentHandler, MAPPING_RULES_ELEMENT);
+				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+				mappingRules = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
+			}
+
+			public String[][] getMappingRules() {
+				String[][] rules = new String[mappingRules.size()][2];
+				for (int index = 0; index < mappingRules.size(); index++) {
+					String[] ruleAttributes = (String[]) mappingRules.get(index);
+					rules[index] = ruleAttributes;
+				}
+				return rules;
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(MAPPING_RULE_ELEMENT)) {
+					new MappingRuleHandler(this, attributes, mappingRules);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+		}
+
+		protected class MappingRuleHandler extends AbstractHandler {
+
+			private final String[] required = new String[] {MAPPING_RULE_FILTER_ATTRIBUTE, MAPPING_RULE_OUTPUT_ATTRIBUTE};
+
+			public MappingRuleHandler(AbstractHandler parentHandler, Attributes attributes, List mappingRules) {
+				super(parentHandler, MAPPING_RULE_ELEMENT);
+				mappingRules.add(parseRequiredAttributes(attributes, required));
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				invalidElement(name, attributes);
+			}
+		}
+
+		protected class ArtifactsHandler extends AbstractHandler {
+
+			private Set artifacts;
+
+			public ArtifactsHandler(AbstractHandler parentHandler, Attributes attributes) {
+				super(parentHandler, ARTIFACTS_ELEMENT);
+				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+				artifacts = (size != null ? new LinkedHashSet(new Integer(size).intValue()) : new LinkedHashSet(4));
+			}
+
+			public Set getArtifacts() {
+				return artifacts;
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(ARTIFACT_ELEMENT)) {
+					new ArtifactHandler(this, attributes, artifacts);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+		}
+
+		protected class ArtifactHandler extends AbstractHandler {
+
+			private final String[] required = new String[] {ARTIFACT_NAMESPACE_ATTRIBUTE, ARTIFACT_CLASSIFIER_ATTRIBUTE, ID_ATTRIBUTE, VERSION_ATTRIBUTE};
+
+			private Set artifacts;
+			ArtifactDescriptor currentArtifact = null;
+
+			private PropertiesHandler propertiesHandler = null;
+			private ProcessingStepsHandler processingStepsHandler = null;
+
+			public ArtifactHandler(AbstractHandler parentHandler, Attributes attributes, Set artifacts) {
+				super(parentHandler, ARTIFACT_ELEMENT);
+				this.artifacts = artifacts;
+				String[] values = parseRequiredAttributes(attributes, required);
+				Version version = checkVersion(ARTIFACT_ELEMENT, VERSION_ATTRIBUTE, values[3]);
+				// TODO: resolve access restriction on ArtifactKey construction
+				currentArtifact = new ArtifactDescriptor(new ArtifactKey(values[0], values[1], values[2], version));
+			}
+
+			public ArtifactDescriptor getArtifact() {
+				return currentArtifact;
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (PROCESSING_STEPS_ELEMENT.equalsIgnoreCase(name)) {
+					if (processingStepsHandler == null) {
+						processingStepsHandler = new ProcessingStepsHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (PROPERTIES_ELEMENT.equalsIgnoreCase(name)) {
+					if (propertiesHandler == null) {
+						propertiesHandler = new PropertiesHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+
+			protected void finished() {
+				if (isValidXML() && currentArtifact != null) {
+					OrderedProperties properties = (propertiesHandler == null ? new OrderedProperties(0) //
+							: propertiesHandler.getProperties());
+					currentArtifact.addProperties(properties);
+					ProcessingStepDescriptor[] processingSteps = (processingStepsHandler == null ? new ProcessingStepDescriptor[0] //
+							: processingStepsHandler.getProcessingSteps());
+					currentArtifact.setProcessingSteps(processingSteps);
+					artifacts.add(currentArtifact);
+				}
+			}
+		}
+
+		protected class ProcessingStepsHandler extends AbstractHandler {
+
+			private List processingSteps;
+
+			public ProcessingStepsHandler(AbstractHandler parentHandler, Attributes attributes) {
+				super(parentHandler, PROCESSING_STEPS_ELEMENT);
+				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+				processingSteps = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
+			}
+
+			public ProcessingStepDescriptor[] getProcessingSteps() {
+				return (ProcessingStepDescriptor[]) processingSteps.toArray(new ProcessingStepDescriptor[processingSteps.size()]);
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(PROCESSING_STEP_ELEMENT)) {
+					new ProcessingStepHandler(this, attributes, processingSteps);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+		}
+
+		protected class ProcessingStepHandler extends AbstractHandler {
+
+			private final String[] required = new String[] {ID_ATTRIBUTE, STEP_DATA_ATTRIBUTE, STEP_REQUIRED_ATTRIBUTE};
+
+			public ProcessingStepHandler(AbstractHandler parentHandler, Attributes attributes, List processingSteps) {
+				super(parentHandler, PROCESSING_STEP_ELEMENT);
+				String[] attributeValues = parseRequiredAttributes(attributes, required);
+				processingSteps.add(new ProcessingStepDescriptor(attributeValues[0], attributeValues[1], checkBoolean(PROCESSING_STEP_ELEMENT, STEP_REQUIRED_ATTRIBUTE, attributeValues[2]).booleanValue()));
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				invalidElement(name, attributes);
+			}
+		}
+
+		protected String getErrorMessage() {
+			return Messages.SimpleArtifactRepositoryIO_Parser_Error_Parsing_Repository;
+		}
+
+		public String toString() {
+			// TODO:
+			return null;
+		}
+
 	}
+
 }
diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/Messages.java b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/Messages.java
new file mode 100644
index 000000000..18c01183e
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/Messages.java
@@ -0,0 +1,31 @@
+/*******************************************************************************
+ * Copyright (c) 2007 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.equinox.internal.p2.artifact.repository;
+
+import org.eclipse.osgi.util.NLS;
+
+public class Messages extends NLS {
+
+	private static final String BUNDLE_NAME = "org.eclipse.equinox.internal.p2.artifact.repository.messages"; //$NON-NLS-1$
+
+	static {
+		// initialize resource bundles
+		NLS.initializeMessages(BUNDLE_NAME, Messages.class);
+	}
+
+	private Messages() {
+		// Do not instantiate
+	}
+
+	public static String SimpleArtifactRepositoryIO_Parser_Error_Parsing_Repository;
+	public static String SimpleArtifactRepositoryIO_Parser_Has_Incompatible_Version;
+
+}
\ No newline at end of file
diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/SimpleArtifactRepository.java b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/SimpleArtifactRepository.java
index 5324f3dfa..bb8c7b0b3 100644
--- a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/SimpleArtifactRepository.java
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/SimpleArtifactRepository.java
@@ -16,6 +16,8 @@ import org.eclipse.core.runtime.*;
 import org.eclipse.equinox.p2.artifact.repository.*;
 import org.eclipse.equinox.p2.artifact.repository.processing.ProcessingStep;
 import org.eclipse.equinox.p2.artifact.repository.processing.ProcessingStepHandler;
+import org.eclipse.equinox.p2.core.helpers.MultiStatus;
+import org.eclipse.equinox.p2.core.helpers.OrderedProperties;
 import org.eclipse.equinox.p2.core.repository.IRepository;
 import org.eclipse.equinox.p2.metadata.IArtifactKey;
 import org.eclipse.equinox.spi.p2.artifact.repository.AbstractArtifactRepository;
@@ -35,7 +37,7 @@ public class SimpleArtifactRepository extends AbstractArtifactRepository impleme
 	protected String[][] mappingRules = DEFAULT_MAPPING_RULES;
 	protected Set artifactDescriptors = new HashSet();
 	private boolean signatureVerification = false;
-	private BlobStore blobStore;
+	private transient BlobStore blobStore;
 
 	public static URL getActualLocation(URL base) {
 		String spec = base.toExternalForm();
@@ -71,6 +73,14 @@ public class SimpleArtifactRepository extends AbstractArtifactRepository impleme
 		blobStore = new BlobStore(getBlobStoreLocation(location), 128);
 	}
 
+	public SimpleArtifactRepository(String name, String type, String version, String description, String provider, boolean verifySignature, Set artifacts, String[][] mappingRules, OrderedProperties properties) {
+		super(name, type, version, null, description, provider);
+		signatureVerification = verifySignature;
+		this.artifactDescriptors.addAll(artifacts);
+		this.mappingRules = mappingRules;
+		this.properties.putAll(properties);
+	}
+
 	private IStatus getArtifact(ArtifactRequest request, IProgressMonitor monitor) {
 		request.setSourceRepository(this);
 		request.perform(monitor);
@@ -171,7 +181,7 @@ public class SimpleArtifactRepository extends AbstractArtifactRepository impleme
 
 	public File getArtifactFile(IArtifactDescriptor descriptor) {
 		String result = getLocation(descriptor);
-		if (result == null || !result.startsWith("file:"))
+		if (result == null || !result.startsWith("file:")) //$NON-NLS-1$
 			return null;
 		return new File(result.substring(5));
 	}
@@ -308,7 +318,8 @@ public class SimpleArtifactRepository extends AbstractArtifactRepository impleme
 
 	public void save() {
 		try {
-			FileOutputStream os = new FileOutputStream(getActualLocation(location).getFile());
+			URL actualLocation = getActualLocation(location);
+			FileOutputStream os = new FileOutputStream(actualLocation.getFile());
 			ArtifactRepositoryIO.write(this, os);
 		} catch (IOException e) {
 			e.printStackTrace();
@@ -341,7 +352,7 @@ public class SimpleArtifactRepository extends AbstractArtifactRepository impleme
 		// Make sure that the file does not exist and that the parents do
 		File outputFile = new File(file);
 		if (outputFile.exists())
-			System.err.println("Artifact repository out of synch. Overwriting " + outputFile.getAbsoluteFile());
+			System.err.println("Artifact repository out of synch. Overwriting " + outputFile.getAbsoluteFile()); //$NON-NLS-1$
 		if (!outputFile.getParentFile().exists() && !outputFile.getParentFile().mkdirs())
 			// TODO: Log an error, or throw an exception?
 			return null;
@@ -434,6 +445,10 @@ public class SimpleArtifactRepository extends AbstractArtifactRepository impleme
 		}
 	}
 
+	public boolean getSignatureVerification() {
+		return signatureVerification;
+	}
+
 	public void setSignatureVerification(boolean value) {
 		signatureVerification = value;
 	}
@@ -449,4 +464,5 @@ public class SimpleArtifactRepository extends AbstractArtifactRepository impleme
 	public boolean isModifiable() {
 		return true;
 	}
+
 }
diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/messages.properties b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/messages.properties
new file mode 100644
index 000000000..bc3cf48db
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/messages.properties
@@ -0,0 +1,15 @@
+###############################################################################
+# Copyright (c) 2007 IBM Corporation and others.
+# All rights reserved. This program and the accompanying materials
+# are made available under the terms of the Eclipse Public License v1.0
+# which accompanies this distribution, and is available at
+# http://www.eclipse.org/legal/epl-v10.html
+#
+# Contributors:
+#     IBM Corporation - initial API and implementation
+###############################################################################
+
+SimpleArtifactRepositoryIO_Parser_Error_Parsing_Repository=\
+	Error parsing simple artifact repository
+SimpleArtifactRepositoryIO_Parser_Has_Incompatible_Version=\
+	Simple artifact repository has incompatible version {0}; expected {1}
\ No newline at end of file
diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/p2/artifact/repository/ArtifactDescriptor.java b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/p2/artifact/repository/ArtifactDescriptor.java
index 207848333..167cd5476 100644
--- a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/p2/artifact/repository/ArtifactDescriptor.java
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/p2/artifact/repository/ArtifactDescriptor.java
@@ -10,8 +10,11 @@
  *******************************************************************************/
 package org.eclipse.equinox.p2.artifact.repository;
 
-import java.util.*;
+import java.util.Arrays;
+import java.util.Map;
 import org.eclipse.equinox.p2.artifact.repository.processing.ProcessingStepDescriptor;
+import org.eclipse.equinox.p2.core.helpers.OrderedProperties;
+import org.eclipse.equinox.p2.core.helpers.UnmodifiableProperties;
 import org.eclipse.equinox.p2.metadata.IArtifactKey;
 
 /**
@@ -26,22 +29,21 @@ public class ArtifactDescriptor implements IArtifactDescriptor {
 	// The list of post processing steps that must be applied one the artifact once it 
 	// has been downloaded (e.g, unpack, then md5 checksum, then...)
 	protected ProcessingStepDescriptor[] processingSteps = EMPTY_STEPS;
-	protected Map properties = new HashMap(2);
+
+	protected OrderedProperties properties = new OrderedProperties();
+
 	protected transient IArtifactRepository repository;
 
-	//QUESTION: Do we need any description or user readable name
+	// QUESTION: Do we need any description or user readable name
 
 	public ArtifactDescriptor(IArtifactDescriptor base) {
 		super();
 		key = base.getArtifactKey();
 		processingSteps = base.getProcessingSteps();
+		properties.putAll(base.getProperties());
 		repository = base.getRepository();
-		// TODO figure out a better way to copy the properties
-		setProperty(IArtifactDescriptor.ARTIFACT_MD5, base.getProperty(IArtifactDescriptor.ARTIFACT_MD5));
-		setProperty(IArtifactDescriptor.ARTIFACT_SIZE, base.getProperty(IArtifactDescriptor.ARTIFACT_SIZE));
-		setProperty(IArtifactDescriptor.DOWNLOAD_MD5, base.getProperty(IArtifactDescriptor.DOWNLOAD_MD5));
-		setProperty(IArtifactDescriptor.DOWNLOAD_SIZE, base.getProperty(IArtifactDescriptor.DOWNLOAD_SIZE));
-		setProperty(IArtifactDescriptor.FORMAT, base.getProperty(IArtifactDescriptor.FORMAT));
+		// TODO this property is hardcoded for the blob store.
+		//		setProperty("artifact.uuid", base.getProperty("artifact.uuid"));
 	}
 
 	public ArtifactDescriptor(ArtifactDescriptor base) {
@@ -61,8 +63,8 @@ public class ArtifactDescriptor implements IArtifactDescriptor {
 		return key;
 	}
 
-	public String getProperty(String key) {
-		return (String) properties.get(key);
+	public String getProperty(String propertyKey) {
+		return (String) properties.get(propertyKey);
 	}
 
 	public void setProperty(String key, String value) {
@@ -72,6 +74,18 @@ public class ArtifactDescriptor implements IArtifactDescriptor {
 			properties.put(key, value);
 	}
 
+	public void addProperties(OrderedProperties additionalProperties) {
+		properties.putAll(additionalProperties);
+	}
+
+	/**
+	 * Returns a read-only collection of the properties of the artifact descriptor.
+	 * @return the properties of this artifact descriptor.
+	 */
+	public Map getProperties() {
+		return new UnmodifiableProperties(properties);
+	}
+
 	public ProcessingStepDescriptor[] getProcessingSteps() {
 		return processingSteps;
 	}
@@ -137,4 +151,5 @@ public class ArtifactDescriptor implements IArtifactDescriptor {
 			return "canonical: " + key.toString(); //$NON-NLS-1$
 		return format + ": " + key.toString(); //$NON-NLS-1$
 	}
+
 }
\ No newline at end of file
diff --git a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/p2/artifact/repository/IArtifactDescriptor.java b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/p2/artifact/repository/IArtifactDescriptor.java
index 6c0271059..eb12b8429 100644
--- a/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/p2/artifact/repository/IArtifactDescriptor.java
+++ b/bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/p2/artifact/repository/IArtifactDescriptor.java
@@ -10,6 +10,7 @@
  *******************************************************************************/
 package org.eclipse.equinox.p2.artifact.repository;
 
+import java.util.Map;
 import org.eclipse.equinox.p2.artifact.repository.processing.ProcessingStepDescriptor;
 import org.eclipse.equinox.p2.metadata.IArtifactKey;
 
@@ -30,11 +31,17 @@ public interface IArtifactDescriptor {
 	/**
 	 * Return the value of the given property in this descriptor  <code>null</code> 
 	 * is returned if no such property exists
-	 * @param key the proerty key to look for
+	 * @param key the property key to look for
 	 * @return the value of the given property or <code>null</code>
 	 */
 	public abstract String getProperty(String key);
 
+	/**
+	 * Returns a read-only collection of the properties of the artifact descriptor.
+	 * @return the properties of this artifact descriptor.
+	 */
+	public Map getProperties();
+
 	/** 
 	 * Return the list of processing steps associated with this descriptor.
 	 * An empty set of steps implies that this descriptor describes a complete
diff --git a/bundles/org.eclipse.equinox.p2.core/META-INF/MANIFEST.MF b/bundles/org.eclipse.equinox.p2.core/META-INF/MANIFEST.MF
index 7d2af04c9..2aad67f79 100644
--- a/bundles/org.eclipse.equinox.p2.core/META-INF/MANIFEST.MF
+++ b/bundles/org.eclipse.equinox.p2.core/META-INF/MANIFEST.MF
@@ -14,7 +14,8 @@ Import-Package: com.thoughtworks.xstream,
  org.eclipse.osgi.service.resolver;version="1.1.0",
  org.eclipse.osgi.util;version="1.0.0",
  org.osgi.framework;version="1.3.0",
- org.osgi.util.tracker;version="1.3.3"
+ org.osgi.util.tracker;version="1.3.3",
+ org.xml.sax
 Export-Package: org.eclipse.equinox.internal.p2.core;x-internal:=true,
  org.eclipse.equinox.p2.core,
  org.eclipse.equinox.p2.core.eventbus,
diff --git a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/Messages.java b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/Messages.java
index 2360b0e7a..65f733618 100644
--- a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/Messages.java
+++ b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/Messages.java
@@ -24,4 +24,17 @@ public class Messages extends NLS {
 	public static String Util_Invalid_Zip_File_Format;
 	public static String Util_Error_Unzipping;
 
+	public static String XMLParser_No_SAX_Parser;
+	public static String XMLParser_Error_At_Line;
+	public static String XMLParser_Error_At_Line_Column;
+	public static String XMLParser_Error_At_Name_Line;
+	public static String XMLParser_Error_At_Name_Line_Column;
+	public static String XMLParser_Missing_Required_Attribute;
+	public static String XMLParser_Unexpected_Attribute;
+	public static String XMLParser_Illegal_Value_For_Attribute;
+	public static String XMLParser_Unexpected_Element;
+	public static String XMLParser_Duplicate_Element;
+	public static String XMLParser_Unexpected_Character_Data;
+	public static String XMLParser_Element_Not_Allowed;
+
 }
diff --git a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/MultiStatus.java b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/MultiStatus.java
index 58b44901c..eabca5077 100644
--- a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/MultiStatus.java
+++ b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/MultiStatus.java
@@ -11,20 +11,20 @@
 package org.eclipse.equinox.p2.core.helpers;
 
 import java.util.*;
-import org.eclipse.core.runtime.IStatus;
-import org.eclipse.core.runtime.Status;
+import org.eclipse.core.runtime.*;
 
 /**
  * An variation of the MultiStatus. Note that this does not
  * extend runtime.MultiStatus, instead it extends Status, because
  * the purpose of this class is to avoid a few shortcomings of
  * runtime.MultiStatus. This is different as follows:
- *      - Add only non-ok status as child (this prevents bloat).
+ *      - Add only non-OK status as child (this prevents bloat).
  *      - Children is a list instead of an array; helps when add()
  *        is called more often than getChildren()
  */
 public class MultiStatus extends Status {
-	public final static String bundleId = "org.eclipse.equinox.p2";
+
+	public final static String bundleId = "org.eclipse.equinox.p2"; //$NON-NLS-1$
 	public static final int STATUS_CODE_SUCCESS = 0;
 
 	// Use ArrayList rather than List so ensureCapacity() is available.
@@ -68,21 +68,21 @@ public class MultiStatus extends Status {
 	}
 
 	/**
-	 * A Multi-Status with an exception.
+	 * A MultiStatus with an exception.
 	 */
 	public MultiStatus(int code, String msg, Throwable exception) {
 		this(code, msg, null, exception);
 	}
 
 	/**
-	 * A Multi-Status with children.
+	 * A MultiStatus with children.
 	 */
 	public MultiStatus(int code, String msg, IStatus[] nested, Throwable exception) {
 		this(OK, bundleId, code, msg, nested, exception);
 	}
 
 	/**
-	 * For creation from outside of the default plugin.
+	 * For creation from outside of the default plug-in.
 	 */
 	public MultiStatus(String pluginId, int code, String msg, Throwable exception) {
 		this(OK, pluginId, code, msg, null, exception);
@@ -96,7 +96,7 @@ public class MultiStatus extends Status {
 	}
 
 	/**
-	 * A Multi-Status with everything.
+	 * A MultiStatus with everything.
 	 */
 	public MultiStatus(int severity, String pluginId, int code, String msg, IStatus[] nested, Throwable exception) {
 		super(severity, pluginId, code, msg, exception);
@@ -113,7 +113,7 @@ public class MultiStatus extends Status {
 	}
 
 	/**
-	 * Does this status indicate an error or cancelation.
+	 * Does this status indicate an error or cancellation.
 	 */
 	public boolean isErrorOrCancel() {
 		return matches(ERROR | CANCEL);
@@ -164,9 +164,9 @@ public class MultiStatus extends Status {
 
 	/**
 	 * Adds the children of the given status as its own
-	 * chldren. This internally uses add(IStatus). This
+	 * children. This internally uses add(IStatus). This
 	 * guards against a null status.
-	 * @param status A multi-status IStatus object whose children
+	 * @param status A MultiStatus IStatus object whose children
 	 * are to be added to this children.
 	 */
 	public void addAll(IStatus status) {
@@ -181,6 +181,26 @@ public class MultiStatus extends Status {
 		}
 	}
 
+	/**
+	 * Merges the given status into this MultiStatus.
+	 * Equivalent to <code>add(status)</code> if the
+	 * given status is not a mMultiStatus. 
+	 * Equivalent to <code>addAll(status)</code> if the
+	 * given status is a MultiStatus. 
+	 *
+	 * @param status the status to merge into this one
+	 * @see #add(IStatus)
+	 * @see #addAll(IStatus)
+	 */
+	public void merge(IStatus status) {
+		Assert.isLegal(status != null);
+		if (!status.isMultiStatus()) {
+			add(status);
+		} else {
+			addAll(status);
+		}
+	}
+
 	/*
 	 * @see IStatus#getChildren()
 	 */
@@ -201,7 +221,7 @@ public class MultiStatus extends Status {
 
 	/**
 	 * Collapses the children into a flat list.
-	 * If all the children are non-multi-status,
+	 * If all the children are non-MultiStatus,
 	 * this is essentially getChildren().
 	 * @return An array of IStatus objects.
 	 * @see #getChildren()
diff --git a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/MultiStatusUtil.java b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/MultiStatusUtil.java
index 0e2bb3800..6872493a9 100644
--- a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/MultiStatusUtil.java
+++ b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/MultiStatusUtil.java
@@ -65,8 +65,8 @@ public class MultiStatusUtil {
 				}
 			}
 			return sb.toString();
-		} else
-			return status.getMessage();
+		}
+		return status.getMessage();
 	}
 
 	public static List getStatusNodes(IStatus root) {
@@ -92,10 +92,8 @@ public class MultiStatusUtil {
 	}
 
 	private static IStatus newNonMultiStatus(IStatus status) {
-		if (status.isMultiStatus())
-			return new Status(status.getSeverity(), status.getPlugin(), status.getCode(), status.getMessage(), status.getException());
-		else
-			return status;
+		return (status.isMultiStatus() ? new Status(status.getSeverity(), status.getPlugin(), status.getCode(), status.getMessage(), status.getException()) //
+				: status);
 	}
 
 	private static void collectStatusNodes(IStatus root, List nodes) {
@@ -176,9 +174,7 @@ public class MultiStatusUtil {
 	}
 
 	private static boolean needsRecoding(IStatus status, IStatusRecoder recoder) {
-		if (!status.isMultiStatus())
-			return recoder.needsRecoding(status);
-		else {
+		if (status.isMultiStatus()) {
 			if (recoder.needsRecoding(status))
 				return true;
 			IStatus[] children = status.getChildren();
@@ -189,6 +185,7 @@ public class MultiStatusUtil {
 			}
 			return false;
 		}
+		return recoder.needsRecoding(status);
 	}
 
 	private static IStatus doSingleRecode(IStatus status, IStatusRecoder recoder) {
diff --git a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/OrderedProperties.java b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/OrderedProperties.java
index 2c8e5b660..7fce86635 100644
--- a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/OrderedProperties.java
+++ b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/OrderedProperties.java
@@ -34,6 +34,11 @@ public class OrderedProperties implements Map {
 		super();
 	}
 
+	public OrderedProperties(int size) {
+		super();
+		propertyMap = new LinkedHashMap(size);
+	}
+
 	/**
 	 * Set the property value.
 	 * <p>
@@ -65,9 +70,7 @@ public class OrderedProperties implements Map {
 	}
 
 	public Collection getPropertyKeysCollection() {
-		if (propertyMap == null)
-			return Collections.EMPTY_LIST;
-		return Collections.unmodifiableCollection(propertyMap.keySet());
+		return (propertyMap != null ? Collections.unmodifiableCollection(propertyMap.keySet()) : Collections.EMPTY_LIST);
 	}
 
 	public String[] getPropertyKeys() {
diff --git a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLConstants.java b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLConstants.java
new file mode 100644
index 000000000..be698b138
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLConstants.java
@@ -0,0 +1,50 @@
+/*******************************************************************************
+ * Copyright (c) 2007 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.equinox.p2.core.helpers;
+
+public interface XMLConstants {
+
+	// Constants used in defining a default processing instruction
+	// including a class name and a version of the associated XML
+	// for some category of objects.
+	//	e.g. <?category class='a.b.c.SomeClass' version='1.2.3'?>
+	//
+	public static final String PI_CLASS_ATTRIBUTE = "class"; //$NON-NLS-1$
+	public static final String PI_VERSION_ATTRIBUTE = "version"; //$NON-NLS-1$
+
+	// Element and attribute names for a standard property collection.
+	//	e.g. <properties size='1'>
+	//			<property name='some_name' value='some_value'/>
+	//		 </properties>
+	public static final String PROPERTIES_ELEMENT = "properties"; //$NON-NLS-1$
+	public static final String PROPERTY_ELEMENT = "property"; //$NON-NLS-1$
+	public static final String PROPERTY_NAME_ATTRIBUTE = "name"; //$NON-NLS-1$
+	public static final String PROPERTY_VALUE_ATTRIBUTE = "value"; //$NON-NLS-1$
+
+	// Constants for the names of common general attributes
+	public static final String ID_ATTRIBUTE = "id"; //$NON-NLS-1$
+	public static final String TYPE_ATTRIBUTE = "type"; //$NON-NLS-1$
+	public static final String NAME_ATTRIBUTE = "name"; //$NON-NLS-1$
+	public static final String VERSION_ATTRIBUTE = "version"; //$NON-NLS-1$
+	public static final String VERSION_RANGE_ATTRIBUTE = "range"; //$NON-NLS-1$
+	public static final String NAMESPACE_ATTRIBUTE = "namespace"; //$NON-NLS-1$
+	public static final String CLASSIFIER_ATTRIBUTE = "classifier"; //$NON-NLS-1$
+	public static final String DESCRIPTION_ATTRIBUTE = "description"; //$NON-NLS-1$
+	public static final String PROVIDER_ATTRIBUTE = "provider"; //$NON-NLS-1$
+
+	// A constant for the name of an attribute of a collection or array element
+	// specifying the size or length
+	public static final String COLLECTION_SIZE_ATTRIBUTE = "size"; //$NON-NLS-1$
+
+	// A constant for an empty array of attribute names
+	public static String[] noAttributes = new String[0];
+
+}
diff --git a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLParser.java b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLParser.java
new file mode 100644
index 000000000..5db1860d6
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLParser.java
@@ -0,0 +1,729 @@
+/*******************************************************************************
+ * Copyright (c) 2007 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.equinox.p2.core.helpers;
+
+import java.util.List;
+import java.util.regex.Pattern;
+import javax.xml.parsers.*;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.Status;
+import org.eclipse.osgi.service.resolver.VersionRange;
+import org.eclipse.osgi.util.NLS;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.Version;
+import org.osgi.util.tracker.ServiceTracker;
+import org.xml.sax.*;
+import org.xml.sax.helpers.DefaultHandler;
+
+public abstract class XMLParser extends DefaultHandler implements XMLConstants {
+
+	// TODO: support logging
+	// Get the logger associated with the class.
+	// protected abstract Logger getLogger();
+
+	// Get the root object that is being parsed.
+	protected abstract Object getRootObject();
+
+	// Get a generic parser error message for inclusion in an error status
+	protected abstract String getErrorMessage();
+
+	protected BundleContext context; // parser class bundle context
+	protected String bundleId; // parser class bundle id
+
+	protected XMLReader xmlReader; // the XML reader for the parser
+	protected ErrorHandler errorHandler; // the error handler for the parser
+
+	protected MultiStatus status = null; // accumulation of non-fatal errors
+	protected Locator locator = null; // document locator, if supported by the parser
+
+	private static ServiceTracker xmlTracker = null;
+
+	public XMLParser(BundleContext context, String pluginId) {
+		super();
+		this.context = context;
+		this.bundleId = pluginId;
+	}
+
+	/**
+	 *  Non-fatal errors accumulated during parsing.
+	 */
+	public IStatus getStatus() {
+		return (status != null ? status : Status.OK_STATUS);
+	}
+
+	public boolean isValidXML() {
+		return (status == null || !status.isErrorOrCancel());
+	}
+
+	private static SAXParserFactory acquireXMLParsing(BundleContext context) {
+		if (xmlTracker == null) {
+			xmlTracker = new ServiceTracker(context, SAXParserFactory.class.getName(), null);
+			xmlTracker.open();
+		}
+		return (SAXParserFactory) xmlTracker.getService();
+	}
+
+	protected static void releaseXMLParsing() {
+		if (xmlTracker != null) {
+			xmlTracker.close();
+		}
+	}
+
+	protected SAXParser getParser() throws ParserConfigurationException, SAXException {
+		SAXParserFactory factory = acquireXMLParsing(this.context);
+		if (factory == null) {
+			throw new SAXException(Messages.XMLParser_No_SAX_Parser);
+		}
+		factory.setNamespaceAware(true);
+		factory.setValidating(true);
+		try {
+			factory.setFeature("http://xml.org/sax/features/string-interning", true); //$NON-NLS-1$
+		} catch (SAXException se) {
+			// some parsers may not support string interning
+		}
+		SAXParser theParser = factory.newSAXParser();
+		if (theParser == null) {
+			throw new SAXException(Messages.XMLParser_No_SAX_Parser);
+		}
+		xmlReader = theParser.getXMLReader();
+		return theParser;
+	}
+
+	public static String makeSimpleName(String localName, String qualifiedName) {
+		if (localName != null && localName.length() > 0) {
+			return localName;
+		}
+		int nameSpaceIndex = qualifiedName.indexOf(":"); //$NON-NLS-1$
+		return (nameSpaceIndex == -1 ? qualifiedName : qualifiedName.substring(nameSpaceIndex + 1));
+	}
+
+	/**
+	 * Set the document locator for the parser
+	 * 
+	 * @see org.xml.sax.ContentHandler#setDocumentLocator
+	 */
+	public void setDocumentLocator(Locator docLocator) {
+		locator = docLocator;
+	}
+
+	/**
+	 * Abstract base class for content handlers
+	 */
+	protected abstract class AbstractHandler extends DefaultHandler {
+
+		protected ContentHandler parentHandler = null;
+		protected String elementHandled = null;
+
+		protected StringBuffer characters = null; // character data inside an element
+
+		public AbstractHandler() {
+			// Empty constructor for a root handler
+		}
+
+		public AbstractHandler(ContentHandler parentHandler) {
+			this.parentHandler = parentHandler;
+			xmlReader.setContentHandler(this);
+		}
+
+		public AbstractHandler(ContentHandler parentHandler, String elementHandled) {
+			this.parentHandler = parentHandler;
+			xmlReader.setContentHandler(this);
+			this.elementHandled = elementHandled;
+		}
+
+		/**
+		 * Set the document locator for the parser
+		 * 
+		 * @see org.xml.sax.ContentHandler#setDocumentLocator
+		 */
+		public void setDocumentLocator(Locator docLocator) {
+			locator = docLocator;
+		}
+
+		public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
+			finishCharacters();
+			String name = makeSimpleName(localName, qName);
+			trace(name, attributes);
+			startElement(name, attributes);
+		}
+
+		public abstract void startElement(String name, Attributes attributes) throws SAXException;
+
+		public void invalidElement(String name, Attributes attributes) {
+			unexpectedElement(this, name, attributes);
+			new IgnoringHandler(this);
+		}
+
+		public void endElement(String namespaceURI, String localName, String qName) {
+			// TODO: throw a bad state error if makeSimpleName(localName, qName) != elementHandled
+			finishCharacters();
+			finished();
+			// Restore the parent content handler
+			xmlReader.setContentHandler(parentHandler);
+		}
+
+		/**
+		 * 	An implementation for startElement when there are no sub-elements
+		 */
+		protected void noSubElements(String name, Attributes attributes) {
+			unexpectedElement(this, name, attributes);
+			// Create a new handler to ignore subsequent nested elements			
+			new IgnoringHandler(this);
+		}
+
+		/*
+		 * Save up character data until endElement or nested startElement
+		 * 
+		 * @see org.xml.sax.ContentHandler#characters
+		 */
+		public void characters(char[] chars, int start, int length) {
+			if (this.characters == null) {
+				this.characters = new StringBuffer();
+			}
+			this.characters.append(chars, start, length);
+		}
+
+		// Consume the characters accumulated in this.characters.
+		// Called before startElement or endElement
+		private String finishCharacters() {
+			// common case -- no characters or only whitespace
+			if (this.characters == null || this.characters.length() == 0) {
+				return null;
+			}
+			if (allWhiteSpace(this.characters)) {
+				this.characters.setLength(0);
+				return null;
+			}
+
+			// process the characters
+			try {
+				String trimmedChars = this.characters.toString().trim();
+				if (trimmedChars.length() == 0) {
+					// this shouldn't happen due to the test for allWhiteSpace above
+					System.err.println("Unexpected non-whitespace characters: " //$NON-NLS-1$
+							+ trimmedChars);
+					return null;
+				}
+				processCharacters(trimmedChars);
+				return trimmedChars;
+			} finally {
+				this.characters.setLength(0);
+			}
+		}
+
+		// Method to override in the handler of an element with CDATA. 
+		protected void processCharacters(String data) {
+			if (data.length() > 0) {
+				unexpectedCharacterData(this, data);
+			}
+		}
+
+		private boolean allWhiteSpace(StringBuffer sb) {
+			int length = sb.length();
+			for (int i = 0; i < length; i += 1) {
+				if (!Character.isWhitespace(sb.charAt(i))) {
+					return false;
+				}
+			}
+			return true;
+		}
+
+		/**
+		 * 	Called when this element and all elements nested into it have been
+		 * 	handled.
+		 */
+		protected void finished() {
+			// Do nothing by default
+		}
+
+		/*
+		 * 	A name used to identify the handler.
+		 */
+		public String getName() {
+			return (elementHandled != null ? elementHandled : "NoName"); //$NON-NLS-1$
+		}
+
+		/**
+		 * Parse the attributes of an element with a single required attribute.
+		 */
+		protected String parseRequiredAttribute(Attributes attributes, String name) {
+			return parseRequiredAttributes(attributes, new String[] {name})[0];
+		}
+
+		/**
+		 * Parse the attributes of an element with two required attributes.
+		 */
+		protected String[] parseRequiredAttributes(Attributes attributes, String name1, String name2) {
+			return parseRequiredAttributes(attributes, new String[] {name1, name2});
+		}
+
+		/**
+		 * Parse the attributes of an element with only required attributes.
+		 */
+		protected String[] parseRequiredAttributes(Attributes attributes, String[] required) {
+			return parseAttributes(attributes, required, noAttributes);
+		}
+
+		/**
+		 * Parse the attributes of an element with a single optional attribute.
+		 */
+		protected String parseOptionalAttribute(Attributes attributes, String name) {
+			return parseAttributes(attributes, noAttributes, new String[] {name})[0];
+		}
+
+		/**
+		 * Parse the attributes of an element, given the list of required and optional ones.
+		 * Return values in same order, null for those not present.
+		 * Report errors for missing required attributes or extra ones.
+		 */
+		protected String[] parseAttributes(Attributes attributes, String[] required, String[] optional) {
+			String[] result = new String[required.length + optional.length];
+			for (int i = 0; i < attributes.getLength(); i += 1) {
+				String name = attributes.getLocalName(i);
+				String value = attributes.getValue(i).trim();
+				int j;
+				if ((j = indexOf(required, name)) >= 0) {
+					result[j] = value;
+				} else if ((j = indexOf(optional, name)) >= 0) {
+					result[required.length + j] = value;
+				} else {
+					unexpectedAttribute(elementHandled, name, value);
+				}
+			}
+			for (int i = 0; i < required.length; i += 1) {
+				checkRequiredAttribute(elementHandled, required[i], result[i]);
+			}
+			return result;
+		}
+
+	}
+
+	/**
+	 *	Handler for an XML document.
+	 *
+	 *	Using the inelegant name 'DocHandler' to clearly distinguish
+	 *	this class from the deprecated org.xml.sax.DocumentHandler.
+	 */
+	protected class DocHandler extends AbstractHandler {
+
+		RootHandler rootHandler;
+
+		public DocHandler(String rootName, RootHandler rootHandler) {
+			super(null, rootName);
+			this.rootHandler = rootHandler;
+		}
+
+		public void ProcessingInstruction(String target, String data) throws SAXException {
+			// Do nothing by default (except suppress warning)
+			if (false) {
+				throw new SAXException(""); //$NON-NLS-1$
+			}
+		}
+
+		public void startElement(String name, Attributes attributes) {
+			if (name.equalsIgnoreCase(elementHandled)) {
+				rootHandler.initialize(this, name, attributes);
+				xmlReader.setContentHandler(rootHandler);
+			} else {
+				this.noSubElements(name, attributes);
+			}
+		}
+
+	}
+
+	/**
+	 * 	Abstract handler for the root element.
+	 */
+	protected abstract class RootHandler extends AbstractHandler {
+
+		public RootHandler() {
+			super();
+		}
+
+		public void initialize(DocHandler document, String rootName, Attributes attributes) {
+			this.parentHandler = document;
+			this.elementHandled = rootName;
+			handleRootAttributes(attributes);
+		}
+
+		protected abstract void handleRootAttributes(Attributes attributes);
+
+	}
+
+	/**
+	 * 	Handler for an ordered properties collection.
+	 */
+	protected class PropertiesHandler extends AbstractHandler {
+
+		private OrderedProperties properties;
+
+		public PropertiesHandler(ContentHandler parentHandler, Attributes attributes) {
+			super(parentHandler, PROPERTIES_ELEMENT);
+			String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+			properties = (size != null ? new OrderedProperties(new Integer(size).intValue()) : new OrderedProperties());
+		}
+
+		public OrderedProperties getProperties() {
+			return properties;
+		}
+
+		public void startElement(String name, Attributes attributes) {
+			if (name.equalsIgnoreCase(PROPERTY_ELEMENT)) {
+				new PropertyHandler(this, attributes, properties);
+			} else {
+				invalidElement(name, attributes);
+			}
+		}
+
+	}
+
+	/**
+	 * 	Handler for a property in an ordered properties collection.
+	 */
+	protected class PropertyHandler extends AbstractHandler {
+
+		public PropertyHandler(ContentHandler parentHandler, Attributes attributes, OrderedProperties properties) {
+			super(parentHandler, PROPERTY_ELEMENT);
+			String[] property = parseProperty(attributes);
+			if (isValidProperty(property)) {
+				properties.setProperty(property[0], property[1]);
+			}
+		}
+
+		public void startElement(String name, Attributes attributes) {
+			invalidElement(name, attributes);
+		}
+
+		private String[] parseProperty(Attributes attributes) {
+			return parseRequiredAttributes(attributes, PROPERTY_NAME_ATTRIBUTE, PROPERTY_VALUE_ATTRIBUTE);
+		}
+
+		private boolean isValidProperty(String[] property) {
+			return (property.length == 2 && property[0] != null && property[1] != null);
+		}
+	}
+
+	/**
+	 * 	Handler for an element with only cdata and no sub-elements.
+	 */
+	protected class TextHandler extends AbstractHandler {
+
+		private String text = null;
+
+		private List texts = null;
+
+		// Constructor for a subclass that processes the attributes
+		public TextHandler(AbstractHandler parent, String elementName) {
+			super(parent, elementName);
+		}
+
+		// Constructor for a subclass with no attributes
+		public TextHandler(AbstractHandler parent, String elementName, Attributes attributes) {
+			super(parent, elementName);
+			parseAttributes(attributes, noAttributes, noAttributes);
+		}
+
+		public TextHandler(AbstractHandler parent, String elementName, Attributes attributes, List texts) {
+			super(parent, elementName);
+			parseAttributes(attributes, noAttributes, noAttributes);
+			this.texts = texts;
+		}
+
+		public String getText() {
+			return (text != null ? text : ""); //$NON-NLS-1$
+		}
+
+		public void startElement(String name, Attributes attributes) {
+			invalidElement(name, attributes);
+		}
+
+		protected void processCharacters(String data) {
+			this.text = data;
+			if (texts != null) {
+				texts.add(getText());
+			}
+		}
+
+	}
+
+	/**
+	 * 	Handler for ignoring content.
+	 */
+	protected class IgnoringHandler extends AbstractHandler {
+
+		public IgnoringHandler(AbstractHandler parent) {
+			super(parent);
+			this.elementHandled = "IgnoringAll"; //$NON-NLS-1$
+		}
+
+		public void startElement(String name, Attributes attributes) {
+			noSubElements(name, attributes);
+		}
+
+	}
+
+	// Helpers for processing instructions that include a Class and/or a Version.
+	private static final String PI_CLASS_REGEX = PI_CLASS_ATTRIBUTE + "=['\"]([\\S]*)['\"]$"; //$NON-NLS-1$
+	private static final Pattern PI_CLASS_PATTERN = Pattern.compile(PI_CLASS_REGEX);
+
+	private static final String PI_VERSION_REGEX = PI_VERSION_ATTRIBUTE + "=['\"]([\\w\\d][\\w\\d\\.]*)['\"]$"; //$NON-NLS-1$
+	private static final Pattern PI_VERSION_PATTERN = Pattern.compile(PI_VERSION_REGEX);
+
+	public String extractPIClass(String data) {
+		return PI_CLASS_PATTERN.matcher(data).replaceAll("$1"); //$NON-NLS-1$
+	}
+
+	public Version extractPIVersion(String target, String data) {
+		return checkVersion(target, PI_VERSION_ATTRIBUTE, PI_VERSION_PATTERN.matcher(data).replaceAll("$1")); //$NON-NLS-1$
+	}
+
+	public class ParserStatus extends Status implements IStatus {
+
+		int lineNumber = 0;
+		int columnNumber = 0;
+
+		public ParserStatus(int severity, int code, String message) {
+			super(severity, MultiStatus.bundleId, code, message, null);
+		}
+
+		public ParserStatus(int severity, int code, String message, int lineNumber, int columnNumber) {
+			super(severity, MultiStatus.bundleId, code, message, null);
+			setLineNumber(lineNumber);
+			setColumnNumber(columnNumber);
+		}
+
+		public int getColumnNumber() {
+			return columnNumber;
+		}
+
+		public void setColumnNumber(int columnNumber) {
+			this.columnNumber = columnNumber;
+		}
+
+		public int getLineNumber() {
+			return lineNumber;
+		}
+
+		public void setLineNumber(int lineNumber) {
+			this.lineNumber = lineNumber;
+		}
+
+	}
+
+	public void error(SAXParseException ex) {
+		addError(ex);
+	}
+
+	public void fatalError(SAXParseException ex) throws SAXException {
+		addError(ex);
+		throw ex;
+	}
+
+	protected void addError(SAXParseException ex) {
+		addError(ex.getMessage());
+	}
+
+	protected String getErrorPrefix() {
+		return null;
+	}
+
+	protected String getErrorSuffix() {
+		return null;
+	}
+
+	// Log an error message and add it to the current status.
+	//
+	// TODO: should we have a flag to throw an exception on error,
+	//		 so parsing can be aborted?
+	// TODO: flag to produce warnings instead of errors? etc. 
+	public final void addError(String msg) {
+		int line = 0;
+		int column = 0;
+		String key = msg;
+		Object[] args = new Object[] {};
+		String root = (getRootObject() == null ? "" //$NON-NLS-1$
+				: " (" + getRootObject() + ")"); //$NON-NLS-1$ //$NON-NLS-2$
+		if (this.locator != null) {
+			String name = this.locator.getSystemId();
+			line = this.locator.getLineNumber();
+			column = this.locator.getColumnNumber();
+			if (line > 0) {
+				args = new Object[] {msg, root, name, new Integer(line), new Integer(column)};
+				if (column > 0) {
+					key = (name != null ? Messages.XMLParser_Error_At_Name_Line_Column //
+							: Messages.XMLParser_Error_At_Line_Column);
+				} else {
+					key = (name != null ? Messages.XMLParser_Error_At_Name_Line //
+							: Messages.XMLParser_Error_At_Line);
+				}
+			}
+		}
+		String errMsg = NLS.bind(key, args);
+		String prefix = getErrorPrefix();
+		String suffix = getErrorSuffix();
+		if (prefix != null) {
+			errMsg = prefix + errMsg;
+		}
+		if (suffix != null) {
+			errMsg = errMsg + suffix;
+		}
+		// TODO: support logging
+		// getLogger().warning(errMsg);
+		IStatus currStatus = new ParserStatus(IStatus.ERROR, IStatus.OK, errMsg, line, column);
+		if (this.status == null) {
+			this.status = new MultiStatus(bundleId, IStatus.OK, new IStatus[] {currStatus}, getErrorMessage(), null);
+		} else {
+			this.status.add(currStatus);
+		}
+	}
+
+	public void trace(String element, Attributes attributes) {
+		// TODO: support logging
+		//		if (!getLogger().isDebugLoggable()) {
+		//			return;
+		//		}
+		//		int indentSize = (this.stateStack != null ? this.stateStack.size() - 1 : 1);
+		//		if (attributes == null) {
+		//			indentSize -= 1;
+		//		}
+		//		char[] indent = new char[2 * indentSize];
+		//		Arrays.fill(indent, ' ');
+		//		StringBuffer sb = new StringBuffer();
+		//		sb.append(indent);
+		//		sb.append('<');
+		//		if (attributes != null) {
+		//			sb.append(element);
+		//			toString(sb, attributes);
+		//		} else {
+		//			sb.append('/').append(element);
+		//		}
+		//		sb.append('>');
+		//		getLogger().debug(sb.toString());
+	}
+
+	private static String toString(Attributes attributes) {
+		StringBuffer result = new StringBuffer();
+		toString(result, attributes);
+		return result.toString();
+	}
+
+	private static void toString(StringBuffer sb, Attributes attributes) {
+		for (int i = 0; i < attributes.getLength(); i += 1) {
+			String name = attributes.getLocalName(i);
+			String value = attributes.getValue(i).trim();
+			sb.append(' ').append(name);
+			sb.append('=').append('"');
+			sb.append(value);
+			sb.append('"');
+		}
+	}
+
+	public void error(String msg) {
+		addError(msg);
+	}
+
+	public void checkRequiredAttribute(String element, String name, Object value) {
+		if (value == null) {
+			addError(NLS.bind(Messages.XMLParser_Missing_Required_Attribute, element, name));
+		}
+	}
+
+	// Check the format of a required boolean attribute
+	public Boolean checkBoolean(String element, String attribute, String value) {
+		try {
+			return Boolean.valueOf(value);
+		} catch (IllegalArgumentException iae) {
+			invalidAttributeValue(element, attribute, value);
+			return Boolean.FALSE;
+		}
+	}
+
+	// Check the format of an optional boolean attribute
+	public Boolean checkBoolean(String element, String attribute, String value, boolean defaultValue) {
+		Boolean result = (defaultValue ? Boolean.TRUE : Boolean.FALSE);
+		if (value != null) {
+			try {
+				return Boolean.valueOf(value);
+			} catch (IllegalArgumentException iae) {
+				invalidAttributeValue(element, attribute, value);
+			}
+		}
+		return result;
+	}
+
+	public Version checkVersion(String element, String attribute, String value) {
+		try {
+			return new Version(value);
+		} catch (IllegalArgumentException iae) {
+			invalidAttributeValue(element, attribute, value);
+		}
+		return Version.emptyVersion;
+	}
+
+	public VersionRange checkVersionRange(String element, String attribute, String value) {
+		try {
+			return new VersionRange(value);
+		} catch (IllegalArgumentException iae) {
+			invalidAttributeValue(element, attribute, value);
+		}
+		return VersionRange.emptyRange;
+	}
+
+	public void unexpectedAttribute(String element, String attribute, String value) {
+		addError(NLS.bind(Messages.XMLParser_Unexpected_Attribute, new Object[] {element, attribute, value}));
+	}
+
+	public void invalidAttributeValue(String element, String attribute, String value) {
+		addError(NLS.bind(Messages.XMLParser_Illegal_Value_For_Attribute, new Object[] {attribute, element, value}));
+	}
+
+	public void unexpectedElement(AbstractHandler handler, String element, Attributes attributes) {
+		addError(NLS.bind(Messages.XMLParser_Unexpected_Element, new Object[] {handler.getName(), element, toString(attributes)}));
+	}
+
+	public void duplicateElement(AbstractHandler handler, String element, Attributes attributes) {
+		addError(NLS.bind(Messages.XMLParser_Duplicate_Element, new Object[] {handler.getName(), element, toString(attributes)}));
+	}
+
+	public void unexpectedCharacterData(AbstractHandler handler, String cdata) {
+		addError(NLS.bind(Messages.XMLParser_Unexpected_Character_Data, handler.getName(), cdata.trim()));
+	}
+
+	/**
+	 * Find the index of the first occurrence of object in array, or -1.
+	 * Use Arrays.binarySearch if array is big and sorted.
+	 */
+	protected static int indexOf(String[] array, String value) {
+		for (int i = 0; i < array.length; i += 1) {
+			if (value == null ? array[i] == null : value.equals(array[i])) {
+				return i;
+			}
+		}
+		return -1;
+	}
+
+	//	public class BadStateError extends AssertionError {
+	//		private static final long serialVersionUID = 1L; // not serialized
+	//
+	//		public BadStateError() {
+	//			super("unexpected state" + //$NON-NLS-1$
+	//					(XMLParser.this.stateStack != null ? ": " + XMLParser.this.stateStack //$NON-NLS-1$
+	//					: "")); //$NON-NLS-1$
+	//		}
+	//
+	//		public BadStateError(String element) {
+	//			super("unexpected state for " + element + //$NON-NLS-1$
+	//					(XMLParser.this.stateStack != null ? ": " + XMLParser.this.stateStack //$NON-NLS-1$
+	//					: "")); //$NON-NLS-1$
+	//		}
+	//	}
+
+}
diff --git a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLUtils.java b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLUtils.java
new file mode 100644
index 000000000..ed72bf65c
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLUtils.java
@@ -0,0 +1,144 @@
+/*******************************************************************************
+ * Copyright (c) 2007 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.equinox.p2.core.helpers;
+
+public class XMLUtils {
+
+	public static String escape(String txt) {
+		// Traverse the string from right to left as the length
+		// may increase as result of processing
+		for (int i = txt.length() - 1; i >= 0; i -= 1) {
+			String replace;
+			switch (txt.charAt(i)) {
+				case '<' :
+					replace = "&lt;"; //$NON-NLS-1$
+					break;
+				case '>' :
+					replace = "&gt;"; //$NON-NLS-1$
+					break;
+				case '"' :
+					replace = "&quot;"; //$NON-NLS-1$
+					break;
+				case '\'' :
+					replace = "&apos;"; //$NON-NLS-1$
+					break;
+				case '&' :
+					replace = "&amp;"; //$NON-NLS-1$
+					break;
+				default :
+					continue;
+			}
+			txt = txt.substring(0, i) + replace + txt.substring(i + 1);
+		}
+		return txt;
+	}
+
+	// A string constant for no indentation.
+	protected static final String NO_INDENT = ""; //$NON-NLS-1$
+
+	// A constant for maximum line length before break and indent
+	protected static final int MAX_LINE = 72;
+
+	/*
+	 *  Construct a string for a simple XML element
+	 *  with no text or child elements, just attributes
+	 *  expressed as name/value pairs.
+	 *  
+	 *  e.g <elemName attr1='value1' attr2='value2'/>
+	 */
+	public static String simpleElement(String elementName, String[] attrNameValuePairs) {
+		StringBuffer buffer = new StringBuffer();
+		simpleElement(elementName, attrNameValuePairs, buffer, NO_INDENT);
+
+		return buffer.toString();
+	}
+
+	/*
+	 *  Write a string for a simple XML element
+	 *  with no text or child elements, just attributes
+	 *  expressed as name/value pairs, into the given
+	 *  string buffer using the given indentation.
+	 *  
+	 *  e.g. <elemName attr1='value1' attr2='value2'/>
+	 */
+	public static void simpleElement(String elementName, String[] attrNameValuePairs, StringBuffer buffer, String indent) {
+		element(elementName, attrNameValuePairs, buffer, indent, "/>"); //$NON-NLS-1$
+	}
+
+	/*
+	 *  Write a string for an open XML element, including
+	 *  the attributes expressed as name/value pairs,
+	 *  into the given string buffer using the given indentation.
+	 *  
+	 *  The caller is responsible for adding any child elements
+	 *  and closing the element.
+	 *  
+	 *  Eg. <elemName attr1='value1' attr2='value2'>
+	 */
+	public static void openElement(String elementName, String[] attrNameValuePairs, StringBuffer buffer, String indent) {
+		element(elementName, attrNameValuePairs, buffer, indent, ">"); //$NON-NLS-1$
+	}
+
+	/*
+	 *  Write a string for an unterminated XML element, including
+	 *  the attributes expressed as name/value pairs,
+	 *  into the given string buffer using the given indentation.
+	 *  
+	 *  The caller is responsible for terminating the element.
+	 *  
+	 *  e.g. <elemName attr1='value1' attr2='value2' 
+	 */
+	public static void unterminatedElement(String elementName, String[] attrNameValuePairs, StringBuffer buffer, String indent) {
+		buffer.append(indent).append('<').append(elementName);
+
+		String attrPrefix = " "; //$NON-NLS-1$
+		int totalLen = buffer.length() + 1;
+		for (int i = 0; i < attrNameValuePairs.length; i++) {
+			String next = attrNameValuePairs[i];
+			if (next != null) {
+				totalLen += next.length() + 2;
+				if (totalLen >= MAX_LINE) {
+					attrPrefix = '\n' + indent + "  "; //$NON-NLS-1$
+					break;
+				}
+			}
+		}
+
+		for (int i = 0; i < attrNameValuePairs.length;) {
+			String name = attrNameValuePairs[i++];
+			if (name.length() > 0) {
+				String value = (i < attrNameValuePairs.length ? attrNameValuePairs[i++] : null);
+				if (value != null) {
+					buffer.append(attrPrefix).append(name);
+					buffer.append("='").append(escape(value)).append('\''); //$NON-NLS-1$
+				}
+			}
+		}
+	}
+
+	/*
+	 *  Fill the string buffer for a XML element, including
+	 *  the attributes expressed as name/value pairs, and
+	 *  terminate with the given termination string.
+	 *  
+	 *  e.g. <elemName attr1='value1' attr2='value2'>
+	 *   or  <elemName attr1='value1' attr2='value2'>
+	 */
+	private static void element(String elementName, String[] attrNameValuePairs, StringBuffer buffer, String indent, String termination) {
+		unterminatedElement(elementName, attrNameValuePairs, buffer, indent);
+		buffer.append(termination);
+	}
+
+	private XMLUtils() {
+		// Private constructor to ensure no instances are created.
+	}
+
+}
diff --git a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLWriter.java b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLWriter.java
new file mode 100644
index 000000000..e5a1fc47d
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/XMLWriter.java
@@ -0,0 +1,348 @@
+/*******************************************************************************
+ * Copyright (c) 2007 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.equinox.p2.core.helpers;
+
+import java.io.*;
+import java.util.*;
+import java.util.regex.Pattern;
+import org.osgi.framework.Version;
+
+public class XMLWriter implements XMLConstants {
+
+	// Miscellaneous
+	public static final String EMPTY_ATTR = ""; //$NON-NLS-1$
+
+	public static class ProcessingInstruction {
+
+		private String target;
+		private String[] data;
+
+		// The standard UTF-8 processing instruction
+		public static final String XML_UTF8 = "<?xml version='1.0' encoding='UTF-8'?>"; //$NON-NLS-1$
+
+		public ProcessingInstruction(String target, String data) {
+			this.target = target;
+			this.data = new String[] {data};
+		}
+
+		public ProcessingInstruction(String target) {
+			this.target = target;
+			this.data = new String[0];
+		}
+
+		public ProcessingInstruction(String target, String[] data) {
+			this.target = target;
+			this.data = data;
+		}
+
+		public ProcessingInstruction(String target, String[] attrs, String[] values) {
+			// Lengths of attributes and values must be the same
+			this.target = target;
+			this.data = new String[attrs.length];
+			for (int i = 0; i < attrs.length; i++) {
+				data[i] = attributeImage(attrs[i], values[i]);
+			}
+		}
+
+		public static ProcessingInstruction makeClassVersionInstruction(String target, Class clazz, Version version) {
+			return new ProcessingInstruction(target, new String[] {PI_CLASS_ATTRIBUTE, PI_VERSION_ATTRIBUTE}, new String[] {clazz.getName(), version.toString()});
+		}
+
+		public String toString() {
+			StringBuffer sb = new StringBuffer("<?"); //$NON-NLS-1$
+			sb.append(this.target).append(' ');
+			for (int i = 0; i < data.length; i++) {
+				sb.append(this.data[i]);
+				if (i < data.length - 1) {
+					sb.append(' ');
+				}
+			}
+			sb.append("?>"); //$NON-NLS-1$
+			return sb.toString();
+		}
+	}
+
+	private Stack elements; // XML elements that have not yet been closed
+	private boolean open; // Can attributes be added to the current element?
+	private String indent; // used for each level of indentation
+
+	private PrintWriter pw;
+
+	private XMLWriter(OutputStream output, boolean writeXMLProcessingInstruction) throws UnsupportedEncodingException {
+		this.pw = new PrintWriter(new OutputStreamWriter(output, "UTF8"), true); //$NON-NLS-1$
+		if (writeXMLProcessingInstruction) {
+			println(ProcessingInstruction.XML_UTF8);
+		}
+		this.elements = new Stack();
+		this.open = false;
+		this.indent = "  "; //$NON-NLS-1$
+	}
+
+	public XMLWriter(OutputStream output, ProcessingInstruction piElement, boolean writeXMLProcessingInstruction) throws UnsupportedEncodingException {
+		this(output, new ProcessingInstruction[] {piElement}, writeXMLProcessingInstruction);
+	}
+
+	public XMLWriter(OutputStream output, ProcessingInstruction piElement) throws UnsupportedEncodingException {
+		this(output, new ProcessingInstruction[] {piElement}, true /* writeXMLProcessingInstruction */);
+	}
+
+	public XMLWriter(OutputStream output, ProcessingInstruction[] piElements, boolean writeXMLProcessingInstruction) throws UnsupportedEncodingException {
+		this(output, writeXMLProcessingInstruction);
+		if (piElements != null) {
+			for (int i = 0; i < piElements.length; i++) {
+				println(piElements[i].toString());
+			}
+		}
+	}
+
+	public XMLWriter(OutputStream output, ProcessingInstruction[] piElements) throws UnsupportedEncodingException {
+		this(output, piElements, /* writeXMLProcessingInstruction */
+		true);
+	}
+
+	// String used for each level of indentation; default is two spaces.
+	public void setIndent(String indent) {
+		this.indent = indent;
+	}
+
+	// start a new element
+	public void start(String name) {
+		if (this.open) {
+			println('>');
+		}
+		indent();
+		print('<');
+		print(name);
+		this.elements.push(name);
+		this.open = true;
+	}
+
+	// end the most recent element with this name
+	public void end(String name) {
+		if (this.elements.empty()) {
+			throw new EndWithoutStartError();
+		}
+		int index = this.elements.search(name);
+		if (index == -1) {
+			throw new EndWithoutStartError(name);
+		}
+		for (int i = 0; i < index; i += 1) {
+			end();
+		}
+	}
+
+	// end the current element
+	public void end() {
+		if (this.elements.empty()) {
+			throw new EndWithoutStartError();
+		}
+		String name = (String) this.elements.pop();
+		if (this.open) {
+			println("/>"); //$NON-NLS-1$
+		} else {
+			printlnIndented("</" + name + '>', false); //$NON-NLS-1$
+		}
+		this.open = false;
+	}
+
+	// write a boolean attribute if it doesn't have the default value
+	public void attribute(String name, boolean value, boolean defaultValue) {
+		if (value != defaultValue) {
+			attribute(name, value);
+		}
+	}
+
+	public void attribute(String name, boolean value) {
+		attribute(name, Boolean.toString(value));
+	}
+
+	public void attribute(String name, int value) {
+		attribute(name, Integer.toString(value));
+	}
+
+	public void attributeOptional(String name, String value) {
+		if (value.length() > 0) {
+			attribute(name, value);
+		}
+	}
+
+	public void attribute(String name, Object value) {
+		if (!this.open) {
+			throw new AttributeAfterNestedContentError();
+		}
+		if (value == null) {
+			return; // optional attribute with no value
+		}
+		print(' ');
+		print(name);
+		print("='"); //$NON-NLS-1$
+		print(XMLUtils.escape(value.toString()));
+		print('\'');
+	}
+
+	public void cdata(String data) {
+		cdata(data, true);
+	}
+
+	public void cdata(String data, boolean escape) {
+		if (this.open) {
+			println('>');
+			this.open = false;
+		}
+		if (data != null) {
+			printlnIndented(data, escape);
+		}
+	}
+
+	public void cdataLines(String data, boolean escape) {
+		if (this.open) {
+			println('>');
+			this.open = false;
+		}
+		if (data.indexOf('\n') == -1) {
+			// simple case: one line
+			printlnIndented(data, escape);
+		} else {
+			String[] lines = Pattern.compile("\\s*\\n").split(data, 0); //$NON-NLS-1$
+			for (int i = 0; i < lines.length; i += 1) {
+				printlnIndented(lines[i].trim(), escape);
+			}
+		}
+	}
+
+	public void flush() {
+		while (!this.elements.empty()) {
+			try {
+				end();
+			} catch (EndWithoutStartError e) {
+				// can't happen
+			}
+		}
+		this.pw.flush();
+	}
+
+	public void close() {
+		flush();
+		this.pw.close();
+	}
+
+	public void writeProperties(Map properties) {
+		writeProperties(PROPERTIES_ELEMENT, properties);
+	}
+
+	public void writeProperties(String propertiesElement, Map properties) {
+		if (properties != null && properties.size() > 0) {
+			start(propertiesElement);
+			attribute(COLLECTION_SIZE_ATTRIBUTE, properties.size());
+			for (Iterator iter = properties.keySet().iterator(); iter.hasNext();) {
+				String name = (String) iter.next();
+				writeProperty(name, (String) properties.get(name));
+			}
+			end(propertiesElement);
+		}
+	}
+
+	// Support writing properties with an auxiliary map
+	// of keys to localized values
+	public void writeProperties(Map properties, Map localizedValues) {
+		writeProperties(PROPERTIES_ELEMENT, properties, localizedValues);
+	}
+
+	// Support writing properties with an auxiliary map
+	// of keys to localized values
+	public void writeProperties(String propertiesElement, Map properties, Map localizedValues) {
+		if (properties != null && properties.size() > 0 && localizedValues != null) {
+			start(propertiesElement);
+			for (Iterator I = properties.entrySet().iterator(); I.hasNext();) {
+				Map.Entry property = (Map.Entry) I.next();
+				String key = (String) property.getKey();
+				String val = (String) property.getValue();
+				if (localizedValues.containsKey(key)) {
+					val = (String) localizedValues.get(key);
+				}
+				writeProperty(key, val);
+			}
+			end(propertiesElement);
+		}
+	}
+
+	public void writeProperty(String name, String value) {
+		start(PROPERTY_ELEMENT);
+		attribute(PROPERTY_NAME_ATTRIBUTE, name);
+		attribute(PROPERTY_VALUE_ATTRIBUTE, value);
+		end();
+	}
+
+	protected static String attributeImage(String name, String value) {
+		if (value == null) {
+			return EMPTY_ATTR; // optional attribute with no value
+		}
+		return name + "='" + XMLUtils.escape(value) + '\''; //$NON-NLS-1$
+	}
+
+	private void println(char c) {
+		this.pw.println(c);
+	}
+
+	private void println(String s) {
+		this.pw.println(s);
+	}
+
+	private void println() {
+		this.pw.println();
+	}
+
+	private void print(char c) {
+		this.pw.print(c);
+	}
+
+	private void print(String s) {
+		this.pw.print(s);
+	}
+
+	private void printlnIndented(String s, boolean escape) {
+		if (s.length() == 0) {
+			println();
+		} else {
+			indent();
+			println(escape ? XMLUtils.escape(s) : s);
+		}
+	}
+
+	private void indent() {
+		for (int i = this.elements.size(); i > 0; i -= 1) {
+			print(this.indent);
+		}
+	}
+
+	public static class AttributeAfterNestedContentError extends Error {
+		private static final long serialVersionUID = 1L; // not serialized
+	}
+
+	public static class EndWithoutStartError extends Error {
+		private static final long serialVersionUID = 1L; // not serialized
+		private String name;
+
+		public EndWithoutStartError() {
+			super();
+		}
+
+		public EndWithoutStartError(String name) {
+			super();
+			this.name = name;
+		}
+
+		public String getName() {
+			return this.name;
+		}
+	}
+
+}
diff --git a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/messages.properties b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/messages.properties
index a5294426c..0f58a17af 100644
--- a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/messages.properties
+++ b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/p2/core/helpers/messages.properties
@@ -12,4 +12,17 @@
 Util_Invalid_Zip_File_Format=Invalid zip file format
 Util_Error_Unzipping=Error unzipping {0}: {1}
 
+# All these errors are bound to 5 args: 0-msg, 1-root, 2-name, 3-line, 4-column
+XMLParser_Error_At_Line=Error at line {3}{1}: {0}
+XMLParser_Error_At_Line_Column=Error at line {3}, column {4}{1}: {0}
+XMLParser_Error_At_Name_Line=Error in {2} at line {3}: {0}
+XMLParser_Error_At_Name_Line_Column=Error in {2} at line {3}, column {4}: {0}
 
+XMLParser_No_SAX_Parser=Unable to acquire a SAX parser service.
+XMLParser_Missing_Required_Attribute=Missing required attribute in "{0}": {1}
+XMLParser_Unexpected_Attribute=Unexpected attribute for element "{0}": {1}="{2}"
+XMLParser_Illegal_Value_For_Attribute=Illegal value for attribute "{0}" of element "{1}": {2}
+XMLParser_Unexpected_Element=Unexpected element in element "{0}": <{1}{2}>
+XMLParser_Duplicate_Element=Duplicate singleton element in element "{0}": <{1}{2}>
+XMLParser_Unexpected_Character_Data=Unexpected character data in element "{0}": {1}
+XMLParser_Element_Not_Allowed=Element "{0}" is not allowed within element "{1}"
diff --git a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/spi/p2/core/repository/AbstractRepository.java b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/spi/p2/core/repository/AbstractRepository.java
index 153abc62d..0f9a9b616 100644
--- a/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/spi/p2/core/repository/AbstractRepository.java
+++ b/bundles/org.eclipse.equinox.p2.core/src/org/eclipse/equinox/spi/p2/core/repository/AbstractRepository.java
@@ -31,7 +31,6 @@ public abstract class AbstractRepository extends PlatformObject implements IRepo
 	protected String version;
 	protected String description;
 	protected String provider;
-	// TODO make sure that this is transiaent.  NO point in storing the location in the repo itself.
 	protected transient URL location;
 	protected OrderedProperties properties = new OrderedProperties();
 
diff --git a/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator CDT bad.launch b/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator CDT bad.launch
new file mode 100644
index 000000000..c2acdb4f9
--- /dev/null
+++ b/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator CDT bad.launch
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<launchConfiguration type="org.eclipse.pde.ui.EquinoxLauncher">
+<booleanAttribute key="automaticAdd" value="false"/>
+<booleanAttribute key="automaticValidate" value="false"/>
+<stringAttribute key="bootstrap" value=""/>
+<stringAttribute key="checked" value="[NONE]"/>
+<booleanAttribute key="clearConfig" value="false"/>
+<stringAttribute key="configLocation" value="${workspace_loc}/.metadata/.plugins/org.eclipse.pde.core/Metadata Generator CDT"/>
+<booleanAttribute key="default_auto_start" value="false"/>
+<intAttribute key="default_start_level" value="4"/>
+<booleanAttribute key="includeOptional" value="false"/>
+<booleanAttribute key="org.eclipse.debug.core.appendEnvironmentVariables" value="true"/>
+<stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="-console&#13;&#10;-consolelog&#13;&#10;-application org.eclipse.equinox.p2.metadata.generator.EclipseGenerator&#13;&#10;-metadataRepository file:C:/Ap2/servers/CDTmetadataRepository/&#13;&#10;-artifactRepository file:C:/Ap2/servers/CDTartifactRepository/&#13;&#10;-source C:/eclipse/CDT4.0 &#13;&#10;-root cdt&#13;&#10;-rootVersion 4.0.0&#13;&#10;-flavor tooling&#13;&#10;-publishArtifacts&#13;&#10;-append"/>
+<stringAttribute key="org.eclipse.jdt.launching.SOURCE_PATH_PROVIDER" value="org.eclipse.pde.ui.workbenchClasspathProvider"/>
+<stringAttribute key="target_bundles" value="org.eclipse.core.contenttype@default:default,org.eclipse.core.jobs@default:default,org.eclipse.core.runtime@default:default,org.eclipse.core.runtime.compatibility.registry@default:default,org.eclipse.equinox.app@default:true,org.eclipse.equinox.common@default:default,org.eclipse.equinox.launcher@default:default,org.eclipse.equinox.launcher.win32.win32.x86@default:default,org.eclipse.equinox.preferences@default:default,org.eclipse.equinox.registry@default:default,org.eclipse.osgi@:,org.eclipse.osgi.services@default:default,org.eclipse.update.configurator@default:default"/>
+<booleanAttribute key="tracing" value="false"/>
+<booleanAttribute key="useDefaultConfigArea" value="true"/>
+<stringAttribute key="vminstall" value="JRE1.4.2"/>
+<stringAttribute key="workspace_bundles" value="com.thoughtworks.xstream@default:default,org.eclipse.ecf@default:default,org.eclipse.ecf.filetransfer@default:default,org.eclipse.ecf.identity@default:default,org.eclipse.equinox.frameworkadmin@default:default,org.eclipse.equinox.frameworkadmin.equinox@default:true,org.eclipse.equinox.p2.artifact.repository@default:default,org.eclipse.equinox.p2.core@default:default,org.eclipse.equinox.p2.download@default:default,org.eclipse.equinox.p2.engine@default:default,org.eclipse.equinox.p2.metadata@default:default,org.eclipse.equinox.p2.metadata.generator@default:default,org.eclipse.equinox.p2.metadata.repository@default:default"/>
+</launchConfiguration>
diff --git a/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator CDT.launch b/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator CDT.launch
index 903a0f163..6ec5e0623 100644
--- a/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator CDT.launch
+++ b/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator CDT.launch
@@ -1,21 +1,22 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <launchConfiguration type="org.eclipse.pde.ui.EquinoxLauncher">
+<booleanAttribute key="append.args" value="true"/>
 <booleanAttribute key="automaticAdd" value="false"/>
 <booleanAttribute key="automaticValidate" value="false"/>
 <stringAttribute key="bootstrap" value=""/>
 <stringAttribute key="checked" value="[NONE]"/>
-<booleanAttribute key="clearConfig" value="true"/>
-<stringAttribute key="configLocation" value="${workspace_loc}/.metadata/.plugins/org.eclipse.pde.core/Metadata Generator CDT"/>
+<booleanAttribute key="clearConfig" value="false"/>
+<stringAttribute key="configLocation" value="${workspace_loc}/.metadata/.plugins/org.eclipse.pde.core/Metadata Generator CDT2"/>
 <booleanAttribute key="default_auto_start" value="false"/>
 <intAttribute key="default_start_level" value="4"/>
-<booleanAttribute key="includeOptional" value="true"/>
+<booleanAttribute key="includeOptional" value="false"/>
 <booleanAttribute key="org.eclipse.debug.core.appendEnvironmentVariables" value="true"/>
-<stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="-console&#13;&#10;-consolelog &#13;&#10;-application org.eclipse.equinox.p2.metadata.generator.EclipseGenerator&#13;&#10;-metadataRepository file:c:/temp/equinox.p2/servers/CDTmetadataRepository/ &#13;&#10;-artifactRepository file:c:/temp/equinox.p2/servers/CDTartifactRepository/ &#13;&#10;-source c:/eclipse/CDT4.0 &#13;&#10;-root cdt&#13;&#10;-flavor tooling&#13;&#10;-publishArtifacts"/>
+<stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="-console&#13;&#10;-consolelog&#13;&#10;-application org.eclipse.equinox.p2.metadata.generator.EclipseGenerator&#13;&#10;-metadataRepository file:C:/Ap2/servers/CDTmetadataRepository/&#13;&#10;-artifactRepository file:C:/Ap2/servers/CDTartifactRepository/&#13;&#10;-source C:/eclipse/CDT4.0 &#13;&#10;-root cdt&#13;&#10;-rootVersion 4.0.0&#13;&#10;-flavor tooling&#13;&#10;-publishArtifacts&#13;&#10;-append"/>
 <stringAttribute key="org.eclipse.jdt.launching.SOURCE_PATH_PROVIDER" value="org.eclipse.pde.ui.workbenchClasspathProvider"/>
-<stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-Declipse.p2.data.area=c:/temp/equinox.p2/agent/ &#13;&#10;-Declipse.p2.metadataRepository=file:c:/temp/equinox.p2/servers/CDTmetadataRepository/ &#13;&#10;-Declipse.p2.artifactRepository=file:c:/temp/equinox.p2/servers/artifactRepository/&#13;&#10;-Declipse.ignoreApp=false&#13;&#10;-Declipse.application.registerDescriptors=true &#13;&#10;-Declipse.application=org.eclipse.equinox.p2.metadata.generator.EclipseGenerator&#13;&#10;-Declipse.p2.metadataGenerator.eclipseBase=c:/eclipse/CDT4.0/&#13;&#10;-Declipse.p2.rootIUId=cdt &#13;&#10;-Declipse.p2.configurationFlavor=tooling&#13;&#10;-Declipse.p2.appendToRepo=true &#13;&#10;-Declipse.p2.generateArtifacts=true"/>
-<stringAttribute key="target_bundles" value="org.eclipse.core.jobs@default:default,org.eclipse.equinox.app@default:true,org.eclipse.equinox.common@default:default,org.eclipse.equinox.launcher@default:default,org.eclipse.equinox.registry@default:default,org.eclipse.osgi@:,org.eclipse.osgi.services@default:default"/>
+<stringAttribute key="pde.version" value="3.3"/>
+<stringAttribute key="target_bundles" value="org.eclipse.core.contenttype@default:default,org.eclipse.core.jobs@default:default,org.eclipse.core.runtime@default:default,org.eclipse.core.runtime.compatibility.registry@default:default,org.eclipse.equinox.app@default:true,org.eclipse.equinox.common@default:default,org.eclipse.equinox.launcher@default:default,org.eclipse.equinox.launcher.win32.win32.x86@default:default,org.eclipse.equinox.preferences@default:default,org.eclipse.equinox.registry@default:default,org.eclipse.osgi@:,org.eclipse.osgi.services@default:default,org.eclipse.update.configurator@default:default"/>
 <booleanAttribute key="tracing" value="false"/>
 <booleanAttribute key="useDefaultConfigArea" value="true"/>
-<stringAttribute key="vminstall" value="jdk"/>
+<stringAttribute key="vminstall" value="JRE1.4.2"/>
 <stringAttribute key="workspace_bundles" value="com.thoughtworks.xstream@default:default,org.eclipse.ecf@default:default,org.eclipse.ecf.filetransfer@default:default,org.eclipse.ecf.identity@default:default,org.eclipse.equinox.frameworkadmin@default:default,org.eclipse.equinox.frameworkadmin.equinox@default:true,org.eclipse.equinox.p2.artifact.repository@default:default,org.eclipse.equinox.p2.core@default:default,org.eclipse.equinox.p2.download@default:default,org.eclipse.equinox.p2.engine@default:default,org.eclipse.equinox.p2.metadata@default:default,org.eclipse.equinox.p2.metadata.generator@default:default,org.eclipse.equinox.p2.metadata.repository@default:default"/>
 </launchConfiguration>
diff --git a/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator SDK.launch b/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator SDK.launch
index 0a6ef35fc..c5ec056d1 100644
--- a/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator SDK.launch
+++ b/bundles/org.eclipse.equinox.p2.metadata.generator/Metadata Generator SDK.launch
@@ -11,12 +11,12 @@
 <intAttribute key="default_start_level" value="4"/>
 <booleanAttribute key="includeOptional" value="false"/>
 <booleanAttribute key="org.eclipse.debug.core.appendEnvironmentVariables" value="true"/>
-<stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="-console &#13;&#10;-consolelog &#13;&#10;-application org.eclipse.equinox.p2.metadata.generator.EclipseGenerator&#13;&#10;-metadataRepository file:d:/tmp/equinox.p2/servers/metadataRepository/ &#13;&#10;-artifactRepository file:d:/tmp/equinox.p2/servers/artifactRepository/ &#13;&#10;-source d:/3.3/eclipse&#13;&#10;-root sdk&#13;&#10;-rootVersion 3.3.0&#13;&#10;-flavor tooling&#13;&#10;-publishArtifacts&#13;&#10;-append"/>
+<stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="-console &#13;&#10;-consolelog&#13;&#10;-application org.eclipse.equinox.p2.metadata.generator.EclipseGenerator&#13;&#10;-metadataRepository file:C:/Ap2/servers2/metadataRepository/ &#13;&#10;-artifactRepository file:C:/Ap2/servers2/artifactRepository/ &#13;&#10;-source C:/eclipse/3.3/eclipse&#13;&#10;-root sdk&#13;&#10;-rootVersion 3.3.0&#13;&#10;-flavor tooling&#13;&#10;-publishArtifacts&#13;&#10;-append"/>
 <stringAttribute key="org.eclipse.jdt.launching.SOURCE_PATH_PROVIDER" value="org.eclipse.pde.ui.workbenchClasspathProvider"/>
 <stringAttribute key="pde.version" value="3.3"/>
-<stringAttribute key="target_bundles" value="org.eclipse.core.contenttype@default:default,org.eclipse.core.jobs@default:default,org.eclipse.core.runtime@default:default,org.eclipse.core.runtime.compatibility.registry@default:default,org.eclipse.equinox.app@default:true,org.eclipse.equinox.common@default:default,org.eclipse.equinox.launcher@default:default,org.eclipse.equinox.launcher.win32.win32.x86@default:default,org.eclipse.equinox.preferences@default:default,org.eclipse.equinox.registry@default:default,org.eclipse.osgi@:,org.eclipse.osgi.services@default:default,org.eclipse.update.configurator@default:default"/>
+<stringAttribute key="target_bundles" value="com.ibm.icu@default:default,org.eclipse.core.contenttype@default:default,org.eclipse.core.jobs@default:default,org.eclipse.core.runtime@default:default,org.eclipse.core.runtime.compatibility.registry@default:default,org.eclipse.equinox.app@default:true,org.eclipse.equinox.common@default:default,org.eclipse.equinox.launcher@default:default,org.eclipse.equinox.launcher.win32.win32.x86@default:default,org.eclipse.equinox.preferences@default:default,org.eclipse.equinox.registry@default:default,org.eclipse.osgi@:,org.eclipse.osgi.services@default:default,org.eclipse.update.configurator@default:default"/>
 <booleanAttribute key="tracing" value="false"/>
 <booleanAttribute key="useDefaultConfigArea" value="true"/>
-<stringAttribute key="vminstall" value="jre1.6.0"/>
-<stringAttribute key="workspace_bundles" value="com.thoughtworks.xstream@default:default,org.eclipse.ecf@default:default,org.eclipse.ecf.filetransfer@default:default,org.eclipse.ecf.identity@default:default,org.eclipse.equinox.frameworkadmin@default:default,org.eclipse.equinox.frameworkadmin.equinox@default:true,org.eclipse.equinox.p2.artifact.repository@default:default,org.eclipse.equinox.p2.core@default:default,org.eclipse.equinox.p2.download@default:default,org.eclipse.equinox.p2.engine@default:default,org.eclipse.equinox.p2.metadata@default:default,org.eclipse.equinox.p2.metadata.generator@default:default,org.eclipse.equinox.p2.metadata.repository@default:default"/>
+<stringAttribute key="vminstall" value="JRE1.4.2"/>
+<stringAttribute key="workspace_bundles" value="com.thoughtworks.xstream@default:default,org.apache.xerces@default:default,org.apache.xml.resolver@default:default,org.eclipse.ecf@default:default,org.eclipse.ecf.filetransfer@default:default,org.eclipse.ecf.identity@default:default,org.eclipse.equinox.frameworkadmin@default:default,org.eclipse.equinox.frameworkadmin.equinox@default:true,org.eclipse.equinox.p2.artifact.repository@default:default,org.eclipse.equinox.p2.core@default:default,org.eclipse.equinox.p2.download@default:default,org.eclipse.equinox.p2.engine@default:default,org.eclipse.equinox.p2.metadata@default:default,org.eclipse.equinox.p2.metadata.generator@default:default,org.eclipse.equinox.p2.metadata.repository@default:default"/>
 </launchConfiguration>
diff --git a/bundles/org.eclipse.equinox.p2.metadata.repository/.classpath b/bundles/org.eclipse.equinox.p2.metadata.repository/.classpath
index 7cdeb7319..ce7393340 100644
--- a/bundles/org.eclipse.equinox.p2.metadata.repository/.classpath
+++ b/bundles/org.eclipse.equinox.p2.metadata.repository/.classpath
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
 	<classpathentry kind="src" path="src"/>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/CDC-1.1%Foundation-1.1"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/J2SE-1.4"/>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="output" path="bin"/>
 </classpath>
diff --git a/bundles/org.eclipse.equinox.p2.metadata.repository/META-INF/MANIFEST.MF b/bundles/org.eclipse.equinox.p2.metadata.repository/META-INF/MANIFEST.MF
index 9d141f2ae..218d5a1bc 100644
--- a/bundles/org.eclipse.equinox.p2.metadata.repository/META-INF/MANIFEST.MF
+++ b/bundles/org.eclipse.equinox.p2.metadata.repository/META-INF/MANIFEST.MF
@@ -10,6 +10,7 @@ Export-Package: org.eclipse.equinox.internal.p2.metadata.repository;x-friends:="
  org.eclipse.equinox.spi.p2.metadata.repository
 Import-Package: com.thoughtworks.xstream,
  org.eclipse.core.runtime.preferences,
+ org.eclipse.equinox.internal.p2.metadata,
  org.eclipse.equinox.p2.core.eventbus,
  org.eclipse.equinox.p2.core.helpers,
  org.eclipse.equinox.p2.core.location,
@@ -22,7 +23,8 @@ Import-Package: com.thoughtworks.xstream,
  org.eclipse.osgi.service.resolver;version="1.1.0",
  org.eclipse.osgi.util;version="1.1.0",
  org.osgi.framework;version="1.3.0",
- org.osgi.service.prefs;version="1.1.0"
+ org.osgi.service.prefs;version="1.1.0",
+ org.xml.sax
 Bundle-Activator: org.eclipse.equinox.internal.p2.metadata.repository.Activator
 Eclipse-LazyStart: true
 Bundle-RequiredExecutionEnvironment: CDC-1.1/Foundation-1.1,
diff --git a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/LocalMetadataRepository.java b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/LocalMetadataRepository.java
index 5a9ebaf4d..1405dcc75 100644
--- a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/LocalMetadataRepository.java
+++ b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/LocalMetadataRepository.java
@@ -35,7 +35,7 @@ public class LocalMetadataRepository extends AbstractMetadataRepository {
 	static final private Integer REPOSITORY_VERSION = new Integer(1);
 	static final private String CONTENT_FILENAME = "content.xml"; //$NON-NLS-1$
 
-	protected HashSet units = new HashSet();
+	protected HashSet units = new LinkedHashSet();
 
 	public static File getActualLocation(URL location) {
 		String spec = location.getFile();
@@ -48,12 +48,20 @@ public class LocalMetadataRepository extends AbstractMetadataRepository {
 		return new File(spec);
 	}
 
+	public LocalMetadataRepository() {
+		super();
+	}
+
 	public LocalMetadataRepository(URL location, String name) throws RepositoryCreationException {
 		super(name == null ? (location != null ? location.toExternalForm() : "") : name, REPOSITORY_TYPE, REPOSITORY_VERSION.toString(), location, null, null);
 		if (!location.getProtocol().equals("file")) //$NON-NLS-1$
 			throw new IllegalArgumentException("Invalid local repository location: " + location);
 	}
 
+	protected LocalMetadataRepository(String name, String type, String version, URL location, String description, String provider) {
+		super(name, type, version, location, description, provider);
+	}
+
 	public IInstallableUnit[] getInstallableUnits(IProgressMonitor monitor) {
 		if (monitor == null) {
 			monitor = new NullProgressMonitor();
@@ -124,4 +132,21 @@ public class LocalMetadataRepository extends AbstractMetadataRepository {
 	public boolean isModifiable() {
 		return true;
 	}
+
+	// Get a non-modifiable collection of the installable units
+	// from the repository.
+	public Set getInstallableUnits() {
+		return Collections.unmodifiableSet(units);
+	}
+
+	public void initialize(RepositoryState state) {
+		this.name = state.Name;
+		this.type = state.Type;
+		this.version = state.Version.toString();
+		this.provider = state.Provider;
+		this.description = state.Description;
+		this.location = state.Location;
+		this.properties = state.Properties;
+		this.units.addAll(Arrays.asList(state.Units));
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/Messages.java b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/Messages.java
index 7d2647a9b..942db82c3 100644
--- a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/Messages.java
+++ b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/Messages.java
@@ -24,4 +24,8 @@ public class Messages extends NLS {
 
 	public static String REPO_LOADING;
 	public static String REPOMGR_ADDING_REPO;
+
+	public static String MetadataRepositoryIO_Parser_Has_Incompatible_Version;
+	public static String MetadataRepositoryIO_Parser_Error_Parsing_Repository;
+
 }
diff --git a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/MetadataRepositoryIO.java b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/MetadataRepositoryIO.java
index b05dec4e1..2e951e17d 100644
--- a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/MetadataRepositoryIO.java
+++ b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/MetadataRepositoryIO.java
@@ -13,8 +13,22 @@ package org.eclipse.equinox.internal.p2.metadata.repository;
 
 import com.thoughtworks.xstream.XStream;
 import java.io.*;
+import java.util.*;
+import javax.xml.parsers.ParserConfigurationException;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.NullProgressMonitor;
+import org.eclipse.equinox.internal.p2.metadata.ArtifactKey;
+import org.eclipse.equinox.p2.core.helpers.*;
 import org.eclipse.equinox.p2.core.repository.RepositoryCreationException;
+import org.eclipse.equinox.p2.metadata.*;
 import org.eclipse.equinox.p2.metadata.repository.IMetadataRepository;
+import org.eclipse.equinox.spi.p2.metadata.repository.AbstractMetadataRepository;
+import org.eclipse.equinox.spi.p2.metadata.repository.AbstractMetadataRepository.RepositoryState;
+import org.eclipse.osgi.service.resolver.VersionRange;
+import org.eclipse.osgi.util.NLS;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.Version;
+import org.xml.sax.*;
 
 /**
  * This class reads and writes provisioning metadata.
@@ -26,6 +40,8 @@ class MetadataRepositoryIO {
 	 * Reads metadata from the given stream, and returns the contained array
 	 * of abstract metadata repositories.
 	 * This method performs buffering, and closes the stream when finished.
+	 * 
+	 * @deprecated
 	 */
 	public static IMetadataRepository read(InputStream input) throws RepositoryCreationException {
 		XStream stream = new XStream();
@@ -43,6 +59,9 @@ class MetadataRepositoryIO {
 		}
 	}
 
+	/**
+	 * 	@deprecated
+	 */
 	public static void write(IMetadataRepository repository, OutputStream output) {
 		XStream stream = new XStream();
 		OutputStream bufferedOutput = null;
@@ -62,4 +81,880 @@ class MetadataRepositoryIO {
 			e.printStackTrace();
 		}
 	}
+
+	public void writeNew(IMetadataRepository repository, OutputStream output) {
+		OutputStream bufferedOutput = null;
+		try {
+			try {
+				bufferedOutput = new BufferedOutputStream(output);
+				Writer repositoryWriter = new Writer(bufferedOutput, repository.getClass());
+				repositoryWriter.write(repository);
+			} finally {
+				if (bufferedOutput != null) {
+					bufferedOutput.close();
+				}
+			}
+		} catch (IOException ioe) {
+			// TODO shouldn't this throw a core exception?
+			ioe.printStackTrace();
+		}
+	}
+
+	/**
+	 * Reads metadata from the given stream, and returns the contained array
+	 * of abstract metadata repositories.
+	 * This method performs buffering, and closes the stream when finished.
+	 */
+	public IMetadataRepository readNew(InputStream input) throws RepositoryCreationException {
+		BufferedInputStream bufferedInput = null;
+		try {
+			try {
+				bufferedInput = new BufferedInputStream(input);
+
+				Parser repositoryParser = new Parser(Activator.getContext(), Activator.ID);
+				repositoryParser.parse(input);
+				if (repositoryParser.isValidXML()) {
+					throw new RepositoryCreationException(new CoreException(repositoryParser.getStatus()));
+				}
+				IMetadataRepository theRepository = repositoryParser.getRepository();
+				// TODO: temporary - try write after read for comparison:
+				//			see note below about call to writeInstallableUnits(...)
+				writeNew(theRepository, new FileOutputStream(new File("C:/Ap2/servers2/metadataRepository/writeback.xml"))); //$NON-NLS-1$
+				return theRepository;
+			} finally {
+				if (bufferedInput != null)
+					bufferedInput.close();
+			}
+		} catch (IOException ioe) {
+			throw new RepositoryCreationException(ioe);
+		}
+	}
+
+	private interface XMLConstants extends org.eclipse.equinox.p2.core.helpers.XMLConstants {
+
+		// Constants defining the structure of the XML for a MetadataRepository
+
+		// A format version number for metadata repository XML.
+		public static final String XML_VERSION = "0.0.1"; //$NON-NLS-1$
+		public static final Version CURRENT_VERSION = new Version(XML_VERSION);
+		public static final VersionRange XML_TOLERANCE = new VersionRange(CURRENT_VERSION, true, CURRENT_VERSION, true);
+
+		// Constants for processing Instructions
+		public static final String PI_REPOSITORY_TARGET = "metadataRepository"; //$NON-NLS-1$
+		//public static XMLWriter.ProcessingInstruction[] PI_DEFAULTS = new XMLWriter.ProcessingInstruction[] {XMLWriter.ProcessingInstruction.makeClassVersionInstruction(PI_REPOSITORY_TARGET, IMetadataRepository.class, CURRENT_VERSION)};
+
+		// Constants for metadata repository elements
+		public static final String REPOSITORY_ELEMENT = "repository"; //$NON-NLS-1$
+		public static final String INSTALLABLE_UNITS_ELEMENT = "units"; //$NON-NLS-1$
+		public static final String INSTALLABLE_UNIT_ELEMENT = "unit"; //$NON-NLS-1$
+		public static final String PROCESSING_STEPS_ELEMENT = "processing"; //$NON-NLS-1$
+		public static final String PROCESSING_STEP_ELEMENT = "step"; //$NON-NLS-1$
+
+		// Constants for sub-elements of an installable unit element
+		public static final String ARTIFACT_KEYS_ELEMENT = "artifacts"; //$NON-NLS-1$
+		public static final String ARTIFACT_KEY_ELEMENT = "artifact"; //$NON-NLS-1$
+		public static final String REQUIRED_CAPABILITIES_ELEMENT = "requires"; //$NON-NLS-1$
+		public static final String REQUIRED_CAPABILITY_ELEMENT = "required"; //$NON-NLS-1$
+		public static final String PROVIDED_CAPABILITIES_ELEMENT = "provides"; //$NON-NLS-1$
+		public static final String PROVIDED_CAPABILITY_ELEMENT = "provided"; //$NON-NLS-1$
+		public static final String TOUCHPOINT_TYPE_ELEMENT = "touchpoint"; //$NON-NLS-1$
+		public static final String TOUCHPOINT_DATA_ELEMENT = "touchpointData"; //$NON-NLS-1$
+		public static final String IU_FILTER_ELEMENT = "filter"; //$NON-NLS-1$
+		public static final String APPLICABILITY_FILTER_ELEMENT = "applicability"; //$NON-NLS-1$
+
+		// Constants for attributes of an installable unit element
+		public static final String SINGLETON_ATTRIBUTE = "singleton"; //$NON-NLS-1$
+		public static final String FRAGMENT_ATTRIBUTE = "fragment"; //$NON-NLS-1$
+
+		// Constants for attributes of a fragment installable unit element
+		public static final String FRAGMENT_HOST_ID_ATTRIBUTE = "hostId"; //$NON-NLS-1$
+		public static final String FRAGMENT_HOST_RANGE_ATTRIBUTE = "hostRange"; //$NON-NLS-1$
+
+		// Constants for sub-elements of a required capability element
+		public static final String CAPABILITY_FILTER_ELEMENT = "filter"; //$NON-NLS-1$
+		public static final String CAPABILITY_SELECTORS_ELEMENT = "selectors"; //$NON-NLS-1$
+		public static final String CAPABILITY_SELECTOR_ELEMENT = "selector"; //$NON-NLS-1$
+
+		// Constants for attributes of a required capability element
+		public static final String CAPABILITY_OPTIONAL_ATTRIBUTE = "optional"; //$NON-NLS-1$
+		public static final String CAPABILITY_MULTIPLE_ATTRIBUTE = "multiple"; //$NON-NLS-1$
+
+		// Constants for attributes of an artifact key element
+		public static final String ARTIFACT_KEY_NAMESPACE_ATTRIBUTE = NAMESPACE_ATTRIBUTE;
+		public static final String ARTIFACT_KEY_CLASSIFIER_ATTRIBUTE = "classifier"; //$NON-NLS-1$
+
+		// Constants for sub-elements of a touchpoint data element
+		public static final String TOUCHPOINT_DATA_INSTRUCTIONS_ELEMENT = "instructions"; //$NON-NLS-1$
+		public static final String TOUCHPOINT_DATA_INSTRUCTION_ELEMENT = "instruction"; //$NON-NLS-1$
+
+		// Constants for attributes of an a touchpoint data instruction element
+		public static final String TOUCHPOINT_DATA_INSTRUCTION_KEY_ATTRIBUTE = "key"; //$NON-NLS-1$
+
+	}
+
+	protected XMLWriter.ProcessingInstruction[] createPI(Class repositoryClass) {
+		return new XMLWriter.ProcessingInstruction[] {XMLWriter.ProcessingInstruction.makeClassVersionInstruction(XMLConstants.PI_REPOSITORY_TARGET, repositoryClass, XMLConstants.CURRENT_VERSION)};
+	}
+
+	// XML writer for a IMetadataRepository
+	protected class Writer extends XMLWriter implements XMLConstants {
+
+		public Writer(OutputStream output, Class repositoryClass) throws IOException {
+			super(output, createPI(repositoryClass));
+		}
+
+		/**
+		 * Write the given metadata repository to the output stream.
+		 */
+		public void write(IMetadataRepository repository) {
+			start(REPOSITORY_ELEMENT);
+			attribute(NAME_ATTRIBUTE, repository.getName());
+			attribute(TYPE_ATTRIBUTE, repository.getType());
+			attribute(VERSION_ATTRIBUTE, repository.getVersion());
+			attributeOptional(PROVIDER_ATTRIBUTE, repository.getProvider());
+			attributeOptional(DESCRIPTION_ATTRIBUTE, repository.getDescription()); // TODO: could be cdata?
+
+			writeProperties(repository.getProperties());
+			writeInstallableUnits(getInstallableUnits(repository));
+
+			end(REPOSITORY_ELEMENT);
+			flush();
+		}
+
+		private IInstallableUnit[] getInstallableUnits(IMetadataRepository repository) {
+			// TODO: there is probably a better solution to the problem.
+			// TODO: Because the implementation of IMetadataRepository.getInstallableUnits
+			//		 in LocalMetadataRepository uses a query, the order of IUs is not preserved
+			//		 write after read. FIX THIS!
+			Set units = null;
+			if (repository instanceof LocalMetadataRepository) {
+				units = ((LocalMetadataRepository) repository).getInstallableUnits();
+			} else if (repository instanceof URLMetadataRepository) {
+				units = ((URLMetadataRepository) repository).getInstallableUnits();
+			} else {
+				return repository.getInstallableUnits(new NullProgressMonitor());
+			}
+			return (units == null ? new IInstallableUnit[0] //
+					: (IInstallableUnit[]) units.toArray(new IInstallableUnit[units.size()]));
+		}
+
+		private void writeInstallableUnits(IInstallableUnit[] installableUnits) {
+			if (installableUnits.length > 0) {
+				start(INSTALLABLE_UNITS_ELEMENT);
+				attribute(COLLECTION_SIZE_ATTRIBUTE, installableUnits.length);
+				for (int i = 0; i < installableUnits.length; i++) {
+					writeInstallableUnit(installableUnits[i]);
+				}
+				end(INSTALLABLE_UNITS_ELEMENT);
+			}
+		}
+
+		private void writeInstallableUnit(IInstallableUnit resolvedIU) {
+			IInstallableUnit iu = (!(resolvedIU instanceof IResolvedInstallableUnit) ? resolvedIU//
+					: ((IResolvedInstallableUnit) resolvedIU).getOriginal());
+			start(INSTALLABLE_UNIT_ELEMENT);
+			attribute(ID_ATTRIBUTE, iu.getId());
+			attribute(VERSION_ATTRIBUTE, iu.getVersion());
+			attribute(SINGLETON_ATTRIBUTE, iu.isSingleton(), true);
+			attribute(FRAGMENT_ATTRIBUTE, iu.isFragment(), false);
+
+			if (iu.isFragment() && iu instanceof IInstallableUnitFragment) {
+				IInstallableUnitFragment fragment = (IInstallableUnitFragment) iu;
+				attribute(FRAGMENT_HOST_ID_ATTRIBUTE, fragment.getHostId());
+				attribute(FRAGMENT_HOST_RANGE_ATTRIBUTE, fragment.getHostVersionRange());
+			}
+
+			writeProperties(iu.getProperties());
+			writeProvidedCapabilities(iu.getProvidedCapabilities());
+			writeRequiredCapabilities(iu.getRequiredCapabilities());
+			writeTrimmedCdata(IU_FILTER_ELEMENT, iu.getFilter());
+			writeTrimmedCdata(APPLICABILITY_FILTER_ELEMENT, iu.getApplicabilityFilter());
+
+			writeArtifactKeys(iu.getArtifacts());
+			writeTouchpointType(iu.getTouchpointType());
+			writeTouchpointData(iu.getTouchpointData());
+
+			end(INSTALLABLE_UNIT_ELEMENT);
+		}
+
+		private void writeProvidedCapabilities(ProvidedCapability[] capabilities) {
+			if (capabilities != null && capabilities.length > 0) {
+				start(PROVIDED_CAPABILITIES_ELEMENT);
+				attribute(COLLECTION_SIZE_ATTRIBUTE, capabilities.length);
+				for (int i = 0; i < capabilities.length; i++) {
+					start(PROVIDED_CAPABILITY_ELEMENT);
+					attribute(NAMESPACE_ATTRIBUTE, capabilities[i].getNamespace());
+					attribute(NAME_ATTRIBUTE, capabilities[i].getName());
+					attribute(VERSION_ATTRIBUTE, capabilities[i].getVersion());
+					end(PROVIDED_CAPABILITY_ELEMENT);
+				}
+				end(PROVIDED_CAPABILITIES_ELEMENT);
+			}
+		}
+
+		private void writeRequiredCapabilities(RequiredCapability[] capabilities) {
+			if (capabilities != null && capabilities.length > 0) {
+				start(REQUIRED_CAPABILITIES_ELEMENT);
+				attribute(COLLECTION_SIZE_ATTRIBUTE, capabilities.length);
+				for (int i = 0; i < capabilities.length; i++) {
+					writeRequiredCapability(capabilities[i]);
+				}
+				end(REQUIRED_CAPABILITIES_ELEMENT);
+			}
+		}
+
+		private void writeRequiredCapability(RequiredCapability capability) {
+			start(REQUIRED_CAPABILITY_ELEMENT);
+			attribute(NAMESPACE_ATTRIBUTE, capability.getNamespace());
+			attribute(NAME_ATTRIBUTE, capability.getName());
+			attribute(VERSION_RANGE_ATTRIBUTE, capability.getRange());
+			attribute(CAPABILITY_OPTIONAL_ATTRIBUTE, capability.isOptional(), false);
+			attribute(CAPABILITY_MULTIPLE_ATTRIBUTE, capability.isMultiple(), false);
+
+			writeTrimmedCdata(CAPABILITY_FILTER_ELEMENT, capability.getFilter());
+
+			String[] selectors = capability.getSelectors();
+			if (selectors.length > 0) {
+				start(CAPABILITY_SELECTORS_ELEMENT);
+				attribute(COLLECTION_SIZE_ATTRIBUTE, selectors.length);
+				for (int j = 0; j < selectors.length; j++) {
+					writeTrimmedCdata(CAPABILITY_SELECTOR_ELEMENT, selectors[j]);
+				}
+				end(CAPABILITY_SELECTORS_ELEMENT);
+			}
+
+			end(REQUIRED_CAPABILITY_ELEMENT);
+		}
+
+		private void writeArtifactKeys(IArtifactKey[] artifactKeys) {
+			if (artifactKeys != null && artifactKeys.length > 0) {
+				start(ARTIFACT_KEYS_ELEMENT);
+				attribute(COLLECTION_SIZE_ATTRIBUTE, artifactKeys.length);
+				for (int i = 0; i < artifactKeys.length; i++) {
+					start(ARTIFACT_KEY_ELEMENT);
+					attribute(ARTIFACT_KEY_NAMESPACE_ATTRIBUTE, artifactKeys[i].getNamespace());
+					attribute(ARTIFACT_KEY_CLASSIFIER_ATTRIBUTE, artifactKeys[i].getClassifier());
+					attribute(ID_ATTRIBUTE, artifactKeys[i].getId());
+					attribute(VERSION_ATTRIBUTE, artifactKeys[i].getVersion());
+					end(ARTIFACT_KEY_ELEMENT);
+				}
+				end(ARTIFACT_KEYS_ELEMENT);
+			}
+		}
+
+		private void writeTouchpointType(TouchpointType touchpointType) {
+			start(TOUCHPOINT_TYPE_ELEMENT);
+			attribute(ID_ATTRIBUTE, touchpointType.getId());
+			attribute(VERSION_ATTRIBUTE, touchpointType.getVersion());
+			end(TOUCHPOINT_TYPE_ELEMENT);
+		}
+
+		private void writeTouchpointData(TouchpointData[] touchpointData) {
+			if (touchpointData != null && touchpointData.length > 0) {
+				start(TOUCHPOINT_DATA_ELEMENT);
+				attribute(COLLECTION_SIZE_ATTRIBUTE, touchpointData.length);
+				for (int i = 0; i < touchpointData.length; i++) {
+					TouchpointData nextData = touchpointData[i];
+					Map instructions = nextData.getInstructions();
+					if (instructions.size() > 0) {
+						start(TOUCHPOINT_DATA_INSTRUCTIONS_ELEMENT);
+						attribute(COLLECTION_SIZE_ATTRIBUTE, instructions.size());
+						for (Iterator iter = instructions.entrySet().iterator(); iter.hasNext();) {
+							Map.Entry entry = (Map.Entry) iter.next();
+							start(TOUCHPOINT_DATA_INSTRUCTION_ELEMENT);
+							attribute(TOUCHPOINT_DATA_INSTRUCTION_KEY_ATTRIBUTE, entry.getKey());
+							cdataLines((String) entry.getValue(), true);
+							end(TOUCHPOINT_DATA_INSTRUCTION_ELEMENT);
+						}
+					}
+				}
+				end(TOUCHPOINT_DATA_ELEMENT);
+			}
+		}
+
+		private void writeTrimmedCdata(String element, String filter) {
+			String trimmed;
+			if (filter != null && (trimmed = filter.trim()).length() > 0) {
+				start(element);
+				cdata(trimmed);
+				end(element);
+			}
+		}
+	}
+
+	/*
+	 * Parser for the contents of a LocalMetadata,
+	 * as written by the Writer class.
+	 */
+	private class Parser extends XMLParser implements XMLConstants {
+
+		private IMetadataRepository theRepository = null;
+		protected Class theRepositoryClass = LocalMetadataRepository.class;
+
+		public Parser(BundleContext context, String bundleId) {
+			super(context, bundleId);
+		}
+
+		public void parse(File file) throws IOException {
+			parse(new FileInputStream(file));
+		}
+
+		public synchronized void parse(InputStream stream) throws IOException {
+			this.status = null;
+			try {
+				// TODO: currently not caching the parser since we make no assumptions
+				//		 or restrictions on concurrent parsing
+				getParser();
+				RepositoryHandler repositoryHandler = new RepositoryHandler();
+				xmlReader.setContentHandler(new RepositoryDocHandler(REPOSITORY_ELEMENT, repositoryHandler));
+				xmlReader.parse(new InputSource(stream));
+				if (isValidXML()) {
+					theRepository = repositoryHandler.getRepository();
+				}
+			} catch (SAXException e) {
+				throw new IOException(e.getMessage());
+			} catch (ParserConfigurationException e) {
+				throw new IOException(e.getMessage());
+			} finally {
+				stream.close();
+			}
+		}
+
+		public IMetadataRepository getRepository() {
+			return theRepository;
+		}
+
+		public Class getRepositoryClass() {
+			return theRepositoryClass;
+		}
+
+		protected Object getRootObject() {
+			return theRepository;
+		}
+
+		public void ProcessingInstruction(String target, String data) throws SAXException {
+			if (PI_REPOSITORY_TARGET.equalsIgnoreCase(target)) {
+				// TODO: should the root handler be constructed based on class
+				// 		 via an extension registry mechanism?
+				String clazz = extractPIClass(data);
+				try {
+					theRepositoryClass = Class.forName(clazz);
+				} catch (ClassNotFoundException e) {
+					// throw new SAXException(NLS.bind(Messages.MetadataRepositoryIO_Repository_Class_Not_Found, clazz));
+					throw new SAXException("Metadata repository class " + clazz + "not found"); //$NON-NLS-1$//$NON-NLS-2$
+				}
+
+				// TODO: version tolerance by extension
+				Version repositoryVersion = extractPIVersion(target, data);
+				if (!XML_TOLERANCE.isIncluded(repositoryVersion)) {
+					throw new SAXException(NLS.bind(Messages.MetadataRepositoryIO_Parser_Has_Incompatible_Version, repositoryVersion, XML_TOLERANCE));
+				}
+			}
+		}
+
+		private final class RepositoryDocHandler extends DocHandler {
+
+			public RepositoryDocHandler(String rootName, RootHandler rootHandler) {
+				super(rootName, rootHandler);
+			}
+		}
+
+		private final class RepositoryHandler extends RootHandler {
+
+			private final String[] required = new String[] {NAME_ATTRIBUTE, TYPE_ATTRIBUTE, VERSION_ATTRIBUTE};
+			private final String[] optional = new String[] {DESCRIPTION_ATTRIBUTE, PROVIDER_ATTRIBUTE};
+
+			private InstallableUnitsHandler unitsHandler = null;
+			private PropertiesHandler propertiesHandler = null;
+
+			private AbstractMetadataRepository repository = null;
+
+			private RepositoryState state = new RepositoryState();
+
+			public RepositoryHandler() {
+				super();
+			}
+
+			public IMetadataRepository getRepository() {
+				return repository;
+			}
+
+			protected void handleRootAttributes(Attributes attributes) {
+				String[] values = parseAttributes(attributes, required, optional);
+				Version version = checkVersion(this.elementHandled, VERSION_ATTRIBUTE, values[2]);
+				state.Name = values[0];
+				state.Type = values[1];
+				state.Version = version;
+				state.Description = values[3];
+				state.Provider = values[4];
+				state.Location = null; // new URL("file://C:/bogus");				
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (PROPERTIES_ELEMENT.equalsIgnoreCase(name)) {
+					if (propertiesHandler == null) {
+						propertiesHandler = new PropertiesHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (INSTALLABLE_UNITS_ELEMENT.equalsIgnoreCase(name)) {
+					if (unitsHandler == null) {
+						unitsHandler = new InstallableUnitsHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+
+			protected void finished() {
+				if (isValidXML()) {
+					//					// TODO: need to support URLMetadataRepository as well.
+					//					try {
+					//						repository = new LocalMetadataRepository(attrValues[0], attrValues[1], attrValues[2], new URL("file://C:/bogus"), attrValues[3], attrValues[4]);
+					//					} catch (MalformedURLException e) {
+					//						// TODO Auto-generated catch block
+					//						e.printStackTrace();
+					//					}
+					state.Properties = (propertiesHandler == null ? new OrderedProperties(0) //
+							: propertiesHandler.getProperties());
+					state.Units = (unitsHandler == null ? new IInstallableUnit[0] //
+							: unitsHandler.getUnits());
+					try {
+						Object repositoryObject = theRepositoryClass.newInstance();
+						if (repositoryObject instanceof AbstractMetadataRepository) {
+							repository = (AbstractMetadataRepository) repositoryObject;
+							repository.initialize(state);
+						}
+					} catch (InstantiationException e) {
+						// TODO: Throw a SAXException
+						e.printStackTrace();
+					} catch (IllegalAccessException e) {
+						// TODO: Throw a SAXException
+						e.printStackTrace();
+					}
+				}
+			}
+		}
+
+		protected class InstallableUnitsHandler extends AbstractHandler {
+
+			private ArrayList units;
+
+			public InstallableUnitsHandler(AbstractHandler parentHandler, Attributes attributes) {
+				super(parentHandler, INSTALLABLE_UNITS_ELEMENT);
+				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+				units = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
+			}
+
+			public IInstallableUnit[] getUnits() {
+				return (IInstallableUnit[]) units.toArray(new IInstallableUnit[units.size()]);
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(INSTALLABLE_UNIT_ELEMENT)) {
+					new InstallableUnitHandler(this, attributes, units);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+		}
+
+		protected class InstallableUnitHandler extends AbstractHandler {
+
+			private final String[] required = new String[] {ID_ATTRIBUTE, VERSION_ATTRIBUTE};
+			private final String[] optional = new String[] {SINGLETON_ATTRIBUTE, FRAGMENT_ATTRIBUTE, FRAGMENT_HOST_ID_ATTRIBUTE, FRAGMENT_HOST_RANGE_ATTRIBUTE};
+
+			InstallableUnit currentUnit = null;
+
+			private PropertiesHandler propertiesHandler = null;
+			private ProvidedCapabilitiesHandler providedCapabilitiesHandler = null;
+			private RequiredCapabilitiesHandler requiredCapabilitiesHandler = null;
+			private TextHandler filterHandler = null;
+			private TextHandler applicabilityHandler = null;
+			private ArtifactsHandler artifactsHandler = null;
+			private TouchpointTypeHandler touchpointTypeHandler = null;
+			private TouchpointDataHandler touchpointDataHandler = null;
+
+			public InstallableUnitHandler(AbstractHandler parentHandler, Attributes attributes, List units) {
+				super(parentHandler, INSTALLABLE_UNIT_ELEMENT);
+				String[] values = parseAttributes(attributes, required, optional);
+
+				Version version = checkVersion(INSTALLABLE_UNIT_ELEMENT, VERSION_ATTRIBUTE, values[1]);
+				boolean singleton = checkBoolean(INSTALLABLE_UNIT_ELEMENT, SINGLETON_ATTRIBUTE, values[2], true).booleanValue();
+				boolean isFragment = checkBoolean(INSTALLABLE_UNIT_ELEMENT, FRAGMENT_ATTRIBUTE, values[3], false).booleanValue();
+				if (isFragment) {
+					// TODO: tooling default fragment does not have a host id
+					// checkRequiredAttribute(INSTALLABLE_UNIT_ELEMENT, FRAGMENT_HOST_ID_ATTRIBUTE, values[4]);
+					checkRequiredAttribute(INSTALLABLE_UNIT_ELEMENT, FRAGMENT_HOST_RANGE_ATTRIBUTE, values[5]);
+					VersionRange hostRange = checkVersionRange(INSTALLABLE_UNIT_ELEMENT, FRAGMENT_HOST_RANGE_ATTRIBUTE, values[5]);
+					currentUnit = new InstallableUnitFragment(values[0], version, singleton, values[4], hostRange);
+				} else {
+					if (values[4] != null) {
+						unexpectedAttribute(INSTALLABLE_UNIT_ELEMENT, FRAGMENT_HOST_ID_ATTRIBUTE, values[4]);
+					} else if (values[5] != null) {
+						unexpectedAttribute(INSTALLABLE_UNIT_ELEMENT, FRAGMENT_HOST_RANGE_ATTRIBUTE, values[4]);
+					}
+					currentUnit = new InstallableUnit(values[0], version, singleton);
+				}
+				units.add(currentUnit);
+			}
+
+			public IInstallableUnit getInstallableUnit() {
+				return currentUnit;
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (PROPERTIES_ELEMENT.equalsIgnoreCase(name)) {
+					if (propertiesHandler == null) {
+						propertiesHandler = new PropertiesHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (PROVIDED_CAPABILITIES_ELEMENT.equalsIgnoreCase(name)) {
+					if (providedCapabilitiesHandler == null) {
+						providedCapabilitiesHandler = new ProvidedCapabilitiesHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (REQUIRED_CAPABILITIES_ELEMENT.equalsIgnoreCase(name)) {
+					if (requiredCapabilitiesHandler == null) {
+						requiredCapabilitiesHandler = new RequiredCapabilitiesHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (IU_FILTER_ELEMENT.equalsIgnoreCase(name)) {
+					if (filterHandler == null) {
+						filterHandler = new TextHandler(this, IU_FILTER_ELEMENT, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (APPLICABILITY_FILTER_ELEMENT.equalsIgnoreCase(name)) {
+					if (applicabilityHandler == null) {
+						applicabilityHandler = new TextHandler(this, APPLICABILITY_FILTER_ELEMENT, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (ARTIFACT_KEYS_ELEMENT.equalsIgnoreCase(name)) {
+					if (artifactsHandler == null) {
+						artifactsHandler = new ArtifactsHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (TOUCHPOINT_TYPE_ELEMENT.equalsIgnoreCase(name)) {
+					if (touchpointTypeHandler == null) {
+						touchpointTypeHandler = new TouchpointTypeHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else if (TOUCHPOINT_DATA_ELEMENT.equalsIgnoreCase(name)) {
+					if (touchpointDataHandler == null) {
+						touchpointDataHandler = new TouchpointDataHandler(this, attributes);
+					} else {
+						duplicateElement(this, name, attributes);
+					}
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+
+			protected void finished() {
+				if (isValidXML() && currentUnit != null) {
+					OrderedProperties properties = (propertiesHandler == null ? new OrderedProperties(0) //
+							: propertiesHandler.getProperties());
+					currentUnit.addProperties(properties);
+					ProvidedCapability[] providedCapabilities = (providedCapabilitiesHandler == null ? new ProvidedCapability[0] //
+							: providedCapabilitiesHandler.getProvidedCapabilities());
+					currentUnit.setCapabilities(providedCapabilities);
+					RequiredCapability[] requiredCapabilities = (requiredCapabilitiesHandler == null ? new RequiredCapability[0] //
+							: requiredCapabilitiesHandler.getRequiredCapabilities());
+					currentUnit.setRequiredCapabilities(requiredCapabilities);
+					if (filterHandler != null) {
+						currentUnit.setFilter(filterHandler.getText());
+					}
+					if (applicabilityHandler != null) {
+						currentUnit.setApplicabilityFilter(applicabilityHandler.getText());
+					}
+					IArtifactKey[] artifacts = (artifactsHandler == null ? new IArtifactKey[0] //
+							: artifactsHandler.getArtifactKeys());
+					currentUnit.setArtifacts(artifacts);
+					if (touchpointTypeHandler != null) {
+						currentUnit.setTouchpointType(touchpointTypeHandler.getTouchpointType());
+					} else {
+						// TODO: create an error
+					}
+					TouchpointData[] touchpointData = (touchpointDataHandler == null ? new TouchpointData[0] //
+							: touchpointDataHandler.getTouchpointData());
+					currentUnit.addTouchpointData(touchpointData);
+				}
+			}
+		}
+
+		protected class ProvidedCapabilitiesHandler extends AbstractHandler {
+
+			private List providedCapabilities;
+
+			public ProvidedCapabilitiesHandler(AbstractHandler parentHandler, Attributes attributes) {
+				super(parentHandler, PROVIDED_CAPABILITIES_ELEMENT);
+				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+				providedCapabilities = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
+			}
+
+			public ProvidedCapability[] getProvidedCapabilities() {
+				return (ProvidedCapability[]) providedCapabilities.toArray(new ProvidedCapability[providedCapabilities.size()]);
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(PROVIDED_CAPABILITY_ELEMENT)) {
+					new ProvidedCapabilityHandler(this, attributes, providedCapabilities);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+		}
+
+		protected class ProvidedCapabilityHandler extends AbstractHandler {
+
+			private final String[] required = new String[] {NAMESPACE_ATTRIBUTE, NAME_ATTRIBUTE, VERSION_ATTRIBUTE};
+
+			public ProvidedCapabilityHandler(AbstractHandler parentHandler, Attributes attributes, List capabilities) {
+				super(parentHandler, PROVIDED_CAPABILITY_ELEMENT);
+				String[] values = parseRequiredAttributes(attributes, required);
+				Version version = checkVersion(PROVIDED_CAPABILITY_ELEMENT, VERSION_ATTRIBUTE, values[2]);
+				capabilities.add(new ProvidedCapability(values[0], values[1], version));
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				invalidElement(name, attributes);
+			}
+		}
+
+		protected class RequiredCapabilitiesHandler extends AbstractHandler {
+
+			private List requiredCapabilities;
+
+			public RequiredCapabilitiesHandler(AbstractHandler parentHandler, Attributes attributes) {
+				super(parentHandler, REQUIRED_CAPABILITIES_ELEMENT);
+				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+				requiredCapabilities = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
+			}
+
+			public RequiredCapability[] getRequiredCapabilities() {
+				return (RequiredCapability[]) requiredCapabilities.toArray(new RequiredCapability[requiredCapabilities.size()]);
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(REQUIRED_CAPABILITY_ELEMENT)) {
+					new RequiredCapabilityHandler(this, attributes, requiredCapabilities);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+		}
+
+		protected class RequiredCapabilityHandler extends AbstractHandler {
+
+			private final String[] required = new String[] {NAMESPACE_ATTRIBUTE, NAME_ATTRIBUTE, VERSION_RANGE_ATTRIBUTE};
+			private final String[] optional = new String[] {CAPABILITY_OPTIONAL_ATTRIBUTE, CAPABILITY_MULTIPLE_ATTRIBUTE};
+
+			private RequiredCapability currentCapability = null;
+
+			private TextHandler filterHandler = null;
+			private CapabilitySelectorsHandler selectorsHandler = null;
+
+			public RequiredCapabilityHandler(AbstractHandler parentHandler, Attributes attributes, List capabilities) {
+				super(parentHandler, REQUIRED_CAPABILITY_ELEMENT);
+				String[] values = parseAttributes(attributes, required, optional);
+				VersionRange range = checkVersionRange(REQUIRED_CAPABILITY_ELEMENT, VERSION_RANGE_ATTRIBUTE, values[2]);
+				boolean isOptional = checkBoolean(REQUIRED_CAPABILITY_ELEMENT, CAPABILITY_OPTIONAL_ATTRIBUTE, values[3], false).booleanValue();
+				boolean isMultiple = checkBoolean(REQUIRED_CAPABILITY_ELEMENT, CAPABILITY_MULTIPLE_ATTRIBUTE, values[4], false).booleanValue();
+				currentCapability = new RequiredCapability(values[0], values[1], range, null, isOptional, isMultiple);
+				capabilities.add(currentCapability);
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(CAPABILITY_FILTER_ELEMENT)) {
+					filterHandler = new TextHandler(this, CAPABILITY_FILTER_ELEMENT, attributes);
+				} else if (name.equalsIgnoreCase(CAPABILITY_SELECTORS_ELEMENT)) {
+					selectorsHandler = new CapabilitySelectorsHandler(this, attributes);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+
+			protected void finished() {
+				if (isValidXML()) {
+					if (currentCapability != null) {
+						if (filterHandler != null) {
+							currentCapability.setFilter(filterHandler.getText());
+						}
+						if (selectorsHandler != null) {
+							currentCapability.setSelectors(selectorsHandler.getSelectors());
+						}
+					}
+				}
+			}
+		}
+
+		protected class ArtifactsHandler extends AbstractHandler {
+
+			private List artifacts;
+
+			public ArtifactsHandler(AbstractHandler parentHandler, Attributes attributes) {
+				super(parentHandler, ARTIFACT_KEYS_ELEMENT);
+				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+				artifacts = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
+			}
+
+			public IArtifactKey[] getArtifactKeys() {
+				return (IArtifactKey[]) artifacts.toArray(new IArtifactKey[artifacts.size()]);
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(ARTIFACT_KEY_ELEMENT)) {
+					new ArtifactHandler(this, attributes, artifacts);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+		}
+
+		protected class ArtifactHandler extends AbstractHandler {
+
+			private final String[] required = new String[] {NAMESPACE_ATTRIBUTE, CLASSIFIER_ATTRIBUTE, ID_ATTRIBUTE, VERSION_ATTRIBUTE};
+
+			public ArtifactHandler(AbstractHandler parentHandler, Attributes attributes, List artifacts) {
+				super(parentHandler, ARTIFACT_KEY_ELEMENT);
+				String[] values = parseRequiredAttributes(attributes, required);
+				Version version = checkVersion(ARTIFACT_KEY_ELEMENT, VERSION_ATTRIBUTE, values[3]);
+				artifacts.add(new ArtifactKey(values[0], values[1], values[2], version));
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				invalidElement(name, attributes);
+			}
+		}
+
+		protected class CapabilitySelectorsHandler extends AbstractHandler {
+
+			private List selectors;
+
+			public CapabilitySelectorsHandler(AbstractHandler parentHandler, Attributes attributes) {
+				super(parentHandler, CAPABILITY_SELECTORS_ELEMENT);
+				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+				selectors = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
+			}
+
+			public String[] getSelectors() {
+				return (String[]) selectors.toArray(new String[selectors.size()]);
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(CAPABILITY_SELECTOR_ELEMENT)) {
+					new TextHandler(this, CAPABILITY_SELECTOR_ELEMENT, attributes, selectors);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+		}
+
+		protected class TouchpointTypeHandler extends AbstractHandler {
+
+			private final String[] required = new String[] {ID_ATTRIBUTE, VERSION_ATTRIBUTE};
+
+			TouchpointType touchpointType = null;
+
+			public TouchpointTypeHandler(AbstractHandler parentHandler, Attributes attributes) {
+				super(parentHandler, TOUCHPOINT_TYPE_ELEMENT);
+				String[] values = parseRequiredAttributes(attributes, required);
+				Version version = checkVersion(TOUCHPOINT_TYPE_ELEMENT, VERSION_ATTRIBUTE, values[1]);
+				touchpointType = new TouchpointType(values[0], version);
+			}
+
+			public TouchpointType getTouchpointType() {
+				return touchpointType;
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				invalidElement(name, attributes);
+			}
+		}
+
+		protected class TouchpointDataHandler extends AbstractHandler {
+
+			TouchpointData touchpointData = null;
+
+			List data = null;
+
+			public TouchpointDataHandler(AbstractHandler parentHandler, Attributes attributes) {
+				super(parentHandler, TOUCHPOINT_DATA_ELEMENT);
+				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+				data = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
+			}
+
+			public TouchpointData[] getTouchpointData() {
+				return (TouchpointData[]) data.toArray(new TouchpointData[data.size()]);
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(TOUCHPOINT_DATA_INSTRUCTIONS_ELEMENT)) {
+					new TouchpointInstructionsHandler(this, attributes, data);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+		}
+
+		protected class TouchpointInstructionsHandler extends AbstractHandler {
+
+			Map instructions = null;
+
+			public TouchpointInstructionsHandler(AbstractHandler parentHandler, Attributes attributes, List data) {
+				super(parentHandler, TOUCHPOINT_DATA_INSTRUCTIONS_ELEMENT);
+				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
+				instructions = (size != null ? new LinkedHashMap(new Integer(size).intValue()) : new LinkedHashMap(4));
+				data.add(new TouchpointData(instructions));
+			}
+
+			public void startElement(String name, Attributes attributes) {
+				if (name.equalsIgnoreCase(TOUCHPOINT_DATA_INSTRUCTION_ELEMENT)) {
+					new TouchpointInstructionHandler(this, attributes, instructions);
+				} else {
+					invalidElement(name, attributes);
+				}
+			}
+		}
+
+		protected class TouchpointInstructionHandler extends TextHandler {
+
+			private final String[] required = new String[] {TOUCHPOINT_DATA_INSTRUCTION_KEY_ATTRIBUTE};
+
+			Map instructions = null;
+			String key = null;
+
+			public TouchpointInstructionHandler(AbstractHandler parentHandler, Attributes attributes, Map instructions) {
+				super(parentHandler, TOUCHPOINT_DATA_INSTRUCTION_ELEMENT);
+				key = parseRequiredAttributes(attributes, required)[0];
+				this.instructions = instructions;
+			}
+
+			protected void finished() {
+				if (isValidXML()) {
+					if (key != null) {
+						instructions.put(key, getText());
+					}
+				}
+			}
+		}
+
+		protected String getErrorMessage() {
+			return Messages.MetadataRepositoryIO_Parser_Error_Parsing_Repository;
+		}
+
+		public String toString() {
+			// TODO:
+			return null;
+		}
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/URLMetadataRepository.java b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/URLMetadataRepository.java
index 9fee1d394..06129b76a 100644
--- a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/URLMetadataRepository.java
+++ b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/URLMetadataRepository.java
@@ -13,14 +13,12 @@ package org.eclipse.equinox.internal.p2.metadata.repository;
 
 import java.net.MalformedURLException;
 import java.net.URL;
-import java.util.HashSet;
-import java.util.Iterator;
+import java.util.*;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.NullProgressMonitor;
 import org.eclipse.equinox.p2.core.repository.RepositoryCreationException;
 import org.eclipse.equinox.p2.metadata.IInstallableUnit;
 import org.eclipse.equinox.p2.metadata.RequiredCapability;
-import org.eclipse.equinox.p2.metadata.repository.IMetadataRepository;
 import org.eclipse.equinox.p2.query.CompoundIterator;
 import org.eclipse.equinox.spi.p2.metadata.repository.AbstractMetadataRepository;
 import org.eclipse.osgi.service.resolver.VersionRange;
@@ -29,14 +27,14 @@ import org.eclipse.osgi.util.NLS;
 /**
  * A metadata repository backed by an arbitrary URL.
  */
-public class URLMetadataRepository extends AbstractMetadataRepository implements IMetadataRepository {
+public class URLMetadataRepository extends AbstractMetadataRepository {
 
 	static final private String REPOSITORY_TYPE = URLMetadataRepository.class.getName();
 	static final private Integer REPOSITORY_VERSION = new Integer(1);
 	static final protected String CONTENT_FILENAME = "content.xml"; //$NON-NLS-1$
 
 	transient protected URL content;
-	protected HashSet units = new HashSet();
+	protected HashSet units = new LinkedHashSet();
 
 	public static URL getActualLocation(URL base) {
 		String spec = base.toExternalForm();
@@ -58,10 +56,14 @@ public class URLMetadataRepository extends AbstractMetadataRepository implements
 	}
 
 	public URLMetadataRepository(URL location, String name) {
-		super(name == null ? (location != null ? location.toExternalForm() : "") : name, REPOSITORY_TYPE, REPOSITORY_VERSION.toString(), location, null, null);
+		super(name == null ? (location != null ? location.toExternalForm() : "") : name, REPOSITORY_TYPE, REPOSITORY_VERSION.toString(), location, null, null); //$NON-NLS-1$
 		content = getActualLocation(location);
 	}
 
+	public URLMetadataRepository() {
+		super();
+	}
+
 	protected boolean load() throws RepositoryCreationException {
 		return new SimpleMetadataRepositoryFactory().load(location) != null;
 	}
@@ -106,4 +108,21 @@ public class URLMetadataRepository extends AbstractMetadataRepository implements
 	public boolean isModifiable() {
 		return false;
 	}
+
+	// Get a non-modifiable collection of the installable units
+	// from the repository.
+	public Set getInstallableUnits() {
+		return Collections.unmodifiableSet(units);
+	}
+
+	public void initialize(RepositoryState state) {
+		this.name = state.Name;
+		this.type = state.Type;
+		this.version = state.Version.toString();
+		this.provider = state.Provider;
+		this.description = state.Description;
+		this.location = state.Location;
+		this.properties = state.Properties;
+		this.units.addAll(Arrays.asList(state.Units));
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/messages.properties b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/messages.properties
index fc369d7ab..cf9c00596 100644
--- a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/messages.properties
+++ b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/internal/p2/metadata/repository/messages.properties
@@ -10,4 +10,9 @@
 ###############################################################################
 
 REPO_LOADING = Loading the repository {0}
-REPOMGR_ADDING_REPO = Adding repository {0}
\ No newline at end of file
+REPOMGR_ADDING_REPO = Adding repository {0}
+
+MetadataRepositoryIO_Parser_Has_Incompatible_Version=\
+	Metadata repository has incompatible version {0}; expected {1}
+MetadataRepositoryIO_Parser_Error_Parsing_Repository=\
+	Error parsing metadata repository
diff --git a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/spi/p2/metadata/repository/AbstractMetadataRepository.java b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/spi/p2/metadata/repository/AbstractMetadataRepository.java
index 99fc32ea5..046dedb2d 100644
--- a/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/spi/p2/metadata/repository/AbstractMetadataRepository.java
+++ b/bundles/org.eclipse.equinox.p2.metadata.repository/src/org/eclipse/equinox/spi/p2/metadata/repository/AbstractMetadataRepository.java
@@ -11,12 +11,31 @@
 package org.eclipse.equinox.spi.p2.metadata.repository;
 
 import java.net.URL;
+import org.eclipse.equinox.p2.core.helpers.OrderedProperties;
 import org.eclipse.equinox.p2.metadata.IInstallableUnit;
 import org.eclipse.equinox.p2.metadata.repository.IMetadataRepository;
 import org.eclipse.equinox.spi.p2.core.repository.AbstractRepository;
+import org.osgi.framework.Version;
 
 public abstract class AbstractMetadataRepository extends AbstractRepository implements IMetadataRepository {
 
+	public static class RepositoryState {
+		public String Name;
+		public String Type;
+		public Version Version;
+		public String Provider;
+		public String Description;
+		public URL Location;
+		public OrderedProperties Properties;
+		public IInstallableUnit[] Units;
+	}
+
+	public AbstractMetadataRepository() {
+		super("noName", "noType", "noVersion", null, null, null); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+	}
+
+	public abstract void initialize(RepositoryState state);
+
 	protected AbstractMetadataRepository(String name, String type, String version, URL location, String description, String provider) {
 		super(name, type, version, location, description, provider);
 	}
diff --git a/bundles/org.eclipse.equinox.p2.metadata/META-INF/MANIFEST.MF b/bundles/org.eclipse.equinox.p2.metadata/META-INF/MANIFEST.MF
index 1eb5ca45b..128f69c30 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/META-INF/MANIFEST.MF
+++ b/bundles/org.eclipse.equinox.p2.metadata/META-INF/MANIFEST.MF
@@ -5,7 +5,7 @@ Bundle-Name: %pluginName
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
 Bundle-Version: 0.1.0.qualifier
-Export-Package: org.eclipse.equinox.internal.p2.metadata;x-friends:="org.eclipse.equinox.p2.metadata.generator",
+Export-Package: org.eclipse.equinox.internal.p2.metadata;x-friends:="org.eclipse.equinox.p2.metadata.generator, org.eclipse.equinox.p2.metadata.repository",
  org.eclipse.equinox.p2.metadata,
  org.eclipse.equinox.p2.query,
  org.eclipse.equinox.p2.resolution
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/IInstallableUnit.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/IInstallableUnit.java
index eeb5e5f2f..0849155a3 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/IInstallableUnit.java
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/IInstallableUnit.java
@@ -8,6 +8,7 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.metadata;
 
+import org.eclipse.equinox.p2.core.helpers.OrderedProperties;
 import org.osgi.framework.Version;
 
 public interface IInstallableUnit extends Comparable {
@@ -62,6 +63,8 @@ public interface IInstallableUnit extends Comparable {
 
 	public abstract String getProperty(String key);
 
+	public abstract OrderedProperties getProperties();
+
 	public abstract TouchpointData[] getTouchpointData();
 
 	public abstract boolean isFragment();
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/InstallableUnit.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/InstallableUnit.java
index f0873c0c0..c2b49c6fe 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/InstallableUnit.java
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/InstallableUnit.java
@@ -8,6 +8,7 @@
  ******************************************************************************/
 package org.eclipse.equinox.p2.metadata;
 
+import java.util.ArrayList;
 import org.eclipse.equinox.internal.p2.metadata.InternalInstallableUnit;
 import org.eclipse.equinox.p2.core.helpers.OrderedProperties;
 import org.eclipse.equinox.p2.core.helpers.UnmodifiableProperties;
@@ -26,7 +27,7 @@ public class InstallableUnit implements IInstallableUnitConstants, IInstallableU
 
 	private IArtifactKey[] artifacts;
 	private TouchpointType touchpointType;
-	private TouchpointData immutableTouchpointData;
+	private ArrayList touchpointData = null;
 
 	private RequiredCapability[] requires;
 
@@ -40,6 +41,14 @@ public class InstallableUnit implements IInstallableUnitConstants, IInstallableU
 		super();
 	}
 
+	public InstallableUnit(String id, Version version, boolean singleton) {
+		super();
+		this.id = id;
+		this.version = version.toString();
+		this.versionObject = version;
+		this.singleton = singleton;
+	}
+
 	public TouchpointType getTouchpointType() {
 		return touchpointType == null ? TouchpointType.NONE : touchpointType;
 	}
@@ -122,10 +131,7 @@ public class InstallableUnit implements IInstallableUnitConstants, IInstallableU
 
 	public String setProperty(String key, String value) {
 		if (value == null)
-			if (properties == null)
-				return null;
-			else
-				return (String) properties.remove(key);
+			return (properties != null ? (String) properties.remove(key) : null);
 		if (properties == null)
 			properties = new OrderedProperties();
 		return (String) properties.setProperty(key, value);
@@ -169,15 +175,34 @@ public class InstallableUnit implements IInstallableUnitConstants, IInstallableU
 	}
 
 	public TouchpointData[] getTouchpointData() {
-		return immutableTouchpointData == null ? TouchpointData.NO_TOUCHPOINT_DATA : new TouchpointData[] {immutableTouchpointData};
+		return (touchpointData == null ? TouchpointData.NO_TOUCHPOINT_DATA //
+				: (TouchpointData[]) touchpointData.toArray(new TouchpointData[touchpointData.size()]));
 	}
 
+	// TODO: resolve the schizophrenia between the singleton immutable data
+	//	   	 and the public returned touchpoint data array.
 	public void setImmutableTouchpointData(TouchpointData immutableData) {
-		this.immutableTouchpointData = immutableData;
+		ensureTouchpointDataCapacity(4);
+		touchpointData.add(immutableData);
 	}
 
-	OrderedProperties getProperties() {
-		return properties == null ? NO_PROPERTIES : properties;
+	public void addTouchpointData(TouchpointData[] newData) {
+		ensureTouchpointDataCapacity(newData.length);
+		for (int i = 0; i < newData.length; i++) {
+			touchpointData.add(newData[i]);
+		}
+	}
+
+	private void ensureTouchpointDataCapacity(int size) {
+		if (touchpointData != null) {
+			touchpointData.ensureCapacity(size);
+		} else {
+			touchpointData = new ArrayList(size);
+		}
+	}
+
+	private OrderedProperties properties() {
+		return (properties != null ? properties : NO_PROPERTIES);
 	}
 
 	/**
@@ -186,8 +211,14 @@ public class InstallableUnit implements IInstallableUnitConstants, IInstallableU
 	 * 
 	 * @return an <i>unmodifiable copy</i> of the IU properties.
 	 */
-	public OrderedProperties copyProperties() {
-		return (properties != null ? new UnmodifiableProperties(getProperties()) : new UnmodifiableProperties(new OrderedProperties()));
+	public OrderedProperties getProperties() {
+		return new UnmodifiableProperties(properties());
+	}
+
+	public void addProperties(OrderedProperties newProperties) {
+		if (properties == null)
+			properties = new OrderedProperties(newProperties.size());
+		properties.putAll(newProperties);
 	}
 
 	public boolean isFragment() {
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/InstallableUnitFragment.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/InstallableUnitFragment.java
index 49383ab34..e60f6abed 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/InstallableUnitFragment.java
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/InstallableUnitFragment.java
@@ -13,13 +13,25 @@ package org.eclipse.equinox.p2.metadata;
 import org.eclipse.osgi.service.resolver.VersionRange;
 import org.osgi.framework.Version;
 
-public class InstallableUnitFragment extends InstallableUnit implements IInstallableUnitFragment, IInstallableUnit {
-	public static ProvidedCapability FRAGMENT_CAPABILITY = new ProvidedCapability(IU_KIND_NAMESPACE, "iu.fragment", new Version(1, 0, 0));
+public class InstallableUnitFragment extends InstallableUnit implements IInstallableUnitFragment {
+
+	public static ProvidedCapability FRAGMENT_CAPABILITY = new ProvidedCapability(IU_KIND_NAMESPACE, "iu.fragment", new Version(1, 0, 0)); //$NON-NLS-1$
 
 	private String hostId;
 	private transient VersionRange hostRangeObject;
 	private String hostRange;
 
+	public InstallableUnitFragment() {
+		super();
+	}
+
+	public InstallableUnitFragment(String id, Version version, boolean singleton, String hostId, VersionRange hostRange) {
+		super(id, version, singleton);
+		this.hostId = hostId;
+		this.hostRange = hostRange.toString();
+		hostRangeObject = hostRange;
+	}
+
 	public ProvidedCapability[] getProvidedCapabilities() {
 		ProvidedCapability[] otherCapabilities = super.getProvidedCapabilities();
 		if (otherCapabilities.length == 0)
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/RequiredCapability.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/RequiredCapability.java
index 7eae09c6f..48f8ac00c 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/RequiredCapability.java
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/RequiredCapability.java
@@ -26,13 +26,13 @@ import org.eclipse.osgi.service.resolver.VersionRange;
  * @see InstallableUnit#IU_NAMESPACE
  */
 public class RequiredCapability {
-	private String filter;
 
-	private boolean multiple;
 	private String name;
 	private String namespace;
-	boolean optional;
 	private String range;
+	private boolean optional;
+	private boolean multiple;
+	private String filter;
 	private String[] selectors;
 	private transient VersionRange rangeObject;
 
@@ -73,6 +73,10 @@ public class RequiredCapability {
 		return filter;
 	}
 
+	public void setFilter(String filter) {
+		this.filter = filter;
+	}
+
 	public String getName() {
 		return name;
 	}
@@ -96,7 +100,7 @@ public class RequiredCapability {
 	}
 
 	public String toString() {
-		return "requiredCapability: " + namespace + '/' + name + '/' + range;
+		return "requiredCapability: " + namespace + '/' + name + '/' + range; //$NON-NLS-1$
 	}
 
 	public int hashCode() {
@@ -155,4 +159,8 @@ public class RequiredCapability {
 	public String[] getSelectors() {
 		return selectors;
 	}
+
+	public void setSelectors(String[] selectors) {
+		this.selectors = selectors;
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/ResolvedInstallableUnit.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/ResolvedInstallableUnit.java
index 6205b90af..88b6d96d8 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/ResolvedInstallableUnit.java
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/ResolvedInstallableUnit.java
@@ -11,6 +11,7 @@ package org.eclipse.equinox.p2.metadata;
 import java.util.ArrayList;
 import java.util.Arrays;
 import org.eclipse.equinox.internal.p2.metadata.InternalInstallableUnit;
+import org.eclipse.equinox.p2.core.helpers.OrderedProperties;
 import org.osgi.framework.Version;
 
 public class ResolvedInstallableUnit implements IResolvedInstallableUnit, InternalInstallableUnit {
@@ -57,6 +58,10 @@ public class ResolvedInstallableUnit implements IResolvedInstallableUnit, Intern
 		return resolved.getProperty(key);
 	}
 
+	public OrderedProperties getProperties() {
+		return resolved.getProperties();
+	}
+
 	public ProvidedCapability[] getProvidedCapabilities() {
 		ArrayList result = new ArrayList();
 		result.addAll(Arrays.asList(resolved.getProvidedCapabilities()));
@@ -124,7 +129,7 @@ public class ResolvedInstallableUnit implements IResolvedInstallableUnit, Intern
 	}
 
 	public String toString() {
-		return "[R]" + resolved.toString();
+		return "[R]" + resolved.toString(); //$NON-NLS-1$
 	}
 
 	public IInstallableUnit getOriginal() {
diff --git a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/TouchpointData.java b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/TouchpointData.java
index 7bfcae9e3..58c0f8590 100644
--- a/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/TouchpointData.java
+++ b/bundles/org.eclipse.equinox.p2.metadata/src/org/eclipse/equinox/p2/metadata/TouchpointData.java
@@ -10,6 +10,7 @@
  *******************************************************************************/
 package org.eclipse.equinox.p2.metadata;
 
+import java.util.Collections;
 import java.util.Map;
 
 public class TouchpointData {
@@ -52,4 +53,10 @@ public class TouchpointData {
 	public String getInstructions(String instructionKey) {
 		return (String) instructions.get(instructionKey);
 	}
+
+	// Return an unmodifiable collection of the instructions
+	// in the touchpoint data.
+	public Map getInstructions() {
+		return Collections.unmodifiableMap(instructions);
+	}
 }
diff --git a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/TestMetadataRepository.java b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/TestMetadataRepository.java
index db639f22f..ce1ca7384 100644
--- a/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/TestMetadataRepository.java
+++ b/bundles/org.eclipse.equinox.p2.tests/src/org/eclipse/equinox/p2/tests/TestMetadataRepository.java
@@ -93,4 +93,15 @@ public class TestMetadataRepository extends AbstractMetadataRepository {
 			units.remove(toRemove[i]);
 		}
 	}
+
+	public void initialize(RepositoryState state) {
+		this.name = state.Name;
+		this.type = state.Type;
+		this.version = state.Version.toString();
+		this.provider = state.Provider;
+		this.description = state.Description;
+		this.location = state.Location;
+		this.properties = state.Properties;
+		this.units.addAll(Arrays.asList(state.Units));
+	}
 }