allow third party contributions to the contextrefs/changes/52/6052/4

This change enables third party plugins to contribute content
to Mylyn context. Third party plugins can register themselves
as IContextContributor and will be asked for additional data
before a save operation on a Mylyn context.
Additionally, they are allowed to receive these additional
data at any time a context is active.
The IContextContributor registration should be enabled as an
extension point in later versions.

Bug: 378399
Change-Id: I704ede7baf022b7718cdb5e58a68405e14b985da

10 files changed, 215 insertions, 3 deletions

diff --git a/org.eclipse.mylyn.context.core/META-INF/MANIFEST.MF b/org.eclipse.mylyn.context.core/META-INF/MANIFEST.MF
index 78ac595..2b90413 100644
--- a/org.eclipse.mylyn.context.core/META-INF/MANIFEST.MF
+++ b/org.eclipse.mylyn.context.core/META-INF/MANIFEST.MF
@@ -8,6 +8,7 @@ Bundle-Localization: plugin
 Require-Bundle: org.eclipse.core.runtime,
  org.eclipse.mylyn.commons.core;bundle-version="[3.8.0,4.0.0)",
  org.eclipse.mylyn.monitor.core;bundle-version="[3.8.0,4.0.0)"
+Import-Package: org.apache.commons.io;version="[1.4.0,3.0.0)"
 Bundle-ActivationPolicy: lazy
 Bundle-Vendor: %Bundle-Vendor
 Export-Package: org.eclipse.mylyn.context.core,
diff --git a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/ContextCore.java b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/ContextCore.java
index 5a17594..2ae4613 100644
--- a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/ContextCore.java
+++ b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/ContextCore.java
@@ -11,6 +11,7 @@
 
 package org.eclipse.mylyn.context.core;
 
+import java.util.List;
 import java.util.Set;
 
 import org.eclipse.mylyn.internal.context.core.ContextCorePlugin;
@@ -57,4 +58,10 @@ public final class ContextCore {
 		return ContextCorePlugin.getContextStore();
 	}
 
+	/**
+	 * @since 3.9
+	 */
+	public static List<IContextContributor> getContextContributor() {
+		return ContextCorePlugin.getDefault().getContextContributor();
+	}
 }
diff --git a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/IContextContributor.java b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/IContextContributor.java
new file mode 100644
index 0000000..34ed795
--- a/dev/null
+++ b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/IContextContributor.java
@@ -0,0 +1,39 @@
+/*******************************************************************************
+ * Copyright (c) 2012 Tasktop Technologies 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:
+ *     Sebastian Schmidt - initial API and implementation
+ *******************************************************************************/
+
+package org.eclipse.mylyn.context.core;
+
+import java.io.InputStream;
+
+/**
+ * A ContextContributor may be used to put additional data to Mylyn context. As the ContextContributor is in charge of
+ * serialization and deserialization of provided data, the data type is not limited.
+ * 
+ * @since 3.8
+ * @noextend This interface is not intended to be extended by clients.
+ * @noimplement This interface is not intended to be implemented by clients.
+ */
+public interface IContextContributor {
+
+	/**
+	 * Provides data which should be added to the given context.
+	 * 
+	 * @param context
+	 *            context that is going to be saved
+	 * @return an InputStream with context related data or null
+	 */
+	public InputStream getDataAsStream(IInteractionContext context);
+
+	/**
+	 * @return an unique identifier for this ContextContributor
+	 */
+	public String getIdentifier();
+}
diff --git a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/IInteractionContextManager.java b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/IInteractionContextManager.java
index 574bae3..6ff14b2 100644
--- a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/IInteractionContextManager.java
+++ b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/context/core/IInteractionContextManager.java
@@ -11,6 +11,7 @@
 
 package org.eclipse.mylyn.context.core;
 
+import java.io.InputStream;
 import java.util.Collection;
 import java.util.Set;
 
@@ -72,4 +73,9 @@ public interface IInteractionContextManager {
 	 * NOTE: If pausing ensure to restore to original state.
 	 */
 	public void setContextCapturePaused(boolean paused);
+
+	/**
+	 * @since 3.9
+	 */
+	public InputStream getAdditionalContextData(IInteractionContext context, String identifier);
 }
\ No newline at end of file
diff --git a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/ContextCorePlugin.java b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/ContextCorePlugin.java
index e294991..fe7ecf8 100644
--- a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/ContextCorePlugin.java
+++ b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/ContextCorePlugin.java
@@ -19,6 +19,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CopyOnWriteArraySet;
 
 import org.eclipse.core.runtime.IConfigurationElement;
@@ -33,6 +34,7 @@ import org.eclipse.core.runtime.Status;
 import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.context.core.AbstractContextStructureBridge;
 import org.eclipse.mylyn.context.core.ContextCore;
+import org.eclipse.mylyn.context.core.IContextContributor;
 import org.eclipse.mylyn.context.core.IInteractionContextScaling;
 import org.osgi.framework.BundleContext;
 
@@ -50,6 +52,8 @@ public class ContextCorePlugin extends Plugin {
 
 	private final Map<String, Set<String>> childContentTypeMap = new ConcurrentHashMap<String, Set<String>>();
 
+	private final List<IContextContributor> contextContributor = new CopyOnWriteArrayList<IContextContributor>();
+
 	// specifies that one content type should shadow another
 	// the <value> content type shadows the <key> content typee
 	private final Map<String, String> contentTypeToShadowMap = new ConcurrentHashMap<String, String>();
@@ -210,6 +214,19 @@ public class ContextCorePlugin extends Plugin {
 		return bridges;
 	}
 
+	public List<IContextContributor> getContextContributor() {
+		return contextContributor;
+	}
+
+	// TODO: add extension point to register context provider
+	public void addContextContributor(IContextContributor contributor) {
+		contextContributor.add(contributor);
+	}
+
+	public void removeContextContributor(IContextContributor contributor) {
+		contextContributor.remove(contributor);
+	}
+
 	/**
 	 * Finds the shadowed content for the passed in base content
 	 * 
diff --git a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/InteractionContextExternalizer.java b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/InteractionContextExternalizer.java
index 134bca6..c63b338 100644
--- a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/InteractionContextExternalizer.java
+++ b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/InteractionContextExternalizer.java
@@ -14,17 +14,24 @@ package org.eclipse.mylyn.internal.context.core;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.net.URLEncoder;
 import java.util.Enumeration;
+import java.util.List;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 import java.util.zip.ZipOutputStream;
 
+import org.apache.commons.io.IOUtils;
 import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.ISafeRunnable;
 import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.SafeRunner;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.context.core.IContextContributor;
 import org.eclipse.mylyn.context.core.IInteractionContext;
 import org.eclipse.mylyn.context.core.IInteractionContextScaling;
 
@@ -144,6 +151,62 @@ public class InteractionContextExternalizer {
 		writer.writeContextToStream(context);
 		outputStream.flush();
 		outputStream.closeEntry();
+
+		addAdditionalInformation(context, outputStream);
+	}
+
+	private void addAdditionalInformation(final IInteractionContext context, final ZipOutputStream outputStream)
+			throws IOException {
+		for (final IContextContributor contributor : getContextContributor()) {
+			SafeRunner.run(new ISafeRunnable() {
+				public void handleException(Throwable e) {
+					StatusHandler.log(new Status(IStatus.WARNING, ContextCorePlugin.ID_PLUGIN,
+							"Context contribution failed: " //$NON-NLS-1$
+									+ contributor.getClass(), e));
+				}
+
+				public void run() throws Exception {
+					InputStream additionalContextInformation = contributor.getDataAsStream(context);
+					if (additionalContextInformation != null) {
+						String encoded = URLEncoder.encode(contributor.getIdentifier(),
+								InteractionContextManager.CONTEXT_FILENAME_ENCODING);
+						ZipEntry zipEntry = new ZipEntry(encoded);
+						outputStream.putNextEntry(zipEntry);
+						IOUtils.copy(additionalContextInformation, outputStream);
+						outputStream.flush();
+						outputStream.closeEntry();
+					}
+				}
+			});
+		}
+	}
+
+	public InputStream getAdditionalInformation(File file, String contributorIdentifier) throws IOException {
+		if (!file.exists()) {
+			return null;
+		}
+		ZipFile zipFile = new ZipFile(file);
+		ZipEntry entry = findFileInZip(zipFile, contributorIdentifier);
+		if (entry == null) {
+			return null;
+		}
+
+		return zipFile.getInputStream(entry);
+	}
+
+	private ZipEntry findFileInZip(ZipFile zipFile, String identifier) throws UnsupportedEncodingException {
+		String encoded = URLEncoder.encode(identifier, InteractionContextManager.CONTEXT_FILENAME_ENCODING);
+		for (Enumeration<?> e = zipFile.entries(); e.hasMoreElements();) {
+			ZipEntry entry = (ZipEntry) e.nextElement();
+			if (entry.getName().equals(encoded)) {
+				return entry;
+			}
+		}
+		return null;
+	}
+
+	private List<IContextContributor> getContextContributor() {
+		return ContextCorePlugin.getDefault().getContextContributor();
 	}
 
 	public IInteractionContext readContextFromXml(String handleIdentifier, File fromFile,
diff --git a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/InteractionContextManager.java b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/InteractionContextManager.java
index a719733..1505bab 100644
--- a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/InteractionContextManager.java
+++ b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/InteractionContextManager.java
@@ -12,6 +12,8 @@
 package org.eclipse.mylyn.internal.context.core;
 
 import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -39,12 +41,12 @@ import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.context.core.AbstractContextListener;
 import org.eclipse.mylyn.context.core.AbstractContextStructureBridge;
 import org.eclipse.mylyn.context.core.ContextChangeEvent;
+import org.eclipse.mylyn.context.core.ContextChangeEvent.ContextChangeKind;
 import org.eclipse.mylyn.context.core.ContextCore;
 import org.eclipse.mylyn.context.core.IInteractionContext;
 import org.eclipse.mylyn.context.core.IInteractionContextManager;
 import org.eclipse.mylyn.context.core.IInteractionElement;
 import org.eclipse.mylyn.context.core.IInteractionRelation;
-import org.eclipse.mylyn.context.core.ContextChangeEvent.ContextChangeKind;
 import org.eclipse.mylyn.monitor.core.InteractionEvent;
 import org.eclipse.mylyn.monitor.core.InteractionEvent.Kind;
 
@@ -420,6 +422,17 @@ public class InteractionContextManager implements IInteractionContextManager {
 		}
 	}
 
+	public InputStream getAdditionalContextData(IInteractionContext context, String contributorIdentifier) {
+		try {
+			return contextStore.getAdditionalContextInformation(context, contributorIdentifier);
+		} catch (IOException e) {
+			StatusHandler.log(new Status(IStatus.WARNING, ContextCorePlugin.ID_PLUGIN,
+					"Searching for additional context data failed" //$NON-NLS-1$
+					, e));
+		}
+		return null;
+	}
+
 	public void deactivateContext(String handleIdentifier) {
 		try {
 			System.setProperty(InteractionContextManager.PROPERTY_CONTEXT_ACTIVE, Boolean.FALSE.toString());
diff --git a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/LocalContextStore.java b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/LocalContextStore.java
index 4801769..e4c7bfa 100644
--- a/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/LocalContextStore.java
+++ b/org.eclipse.mylyn.context.core/src/org/eclipse/mylyn/internal/context/core/LocalContextStore.java
@@ -13,6 +13,7 @@ package org.eclipse.mylyn.internal.context.core;
 
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
 import java.util.ArrayList;
@@ -82,6 +83,12 @@ public class LocalContextStore implements IContextStore {
 		return loadContext(handleIdentifier, getFileForContext(handleIdentifier), commonContextScaling);
 	}
 
+	public InputStream getAdditionalContextInformation(IInteractionContext context, String identifier)
+			throws IOException {
+		File fileForContext = getFileForContext(context.getHandleIdentifier());
+		return externalizer.getAdditionalInformation(fileForContext, identifier);
+	}
+
 	public IInteractionContext importContext(String handleIdentifier, File fromFile) throws CoreException {
 		InteractionContext context;
 		String handleToImportFrom;
diff --git a/org.eclipse.mylyn.context.tests/META-INF/MANIFEST.MF b/org.eclipse.mylyn.context.tests/META-INF/MANIFEST.MF
index 3ef8ce2..0cae2cb 100644
--- a/org.eclipse.mylyn.context.tests/META-INF/MANIFEST.MF
+++ b/org.eclipse.mylyn.context.tests/META-INF/MANIFEST.MF
@@ -17,7 +17,10 @@ Require-Bundle: org.junit,
  org.eclipse.mylyn.context.sdk.util,
  org.eclipse.mylyn.context.ui,
  org.eclipse.mylyn.monitor.core,
- org.eclipse.mylyn.monitor.ui
+ org.eclipse.mylyn.monitor.ui,
+ org.mockito;bundle-version="[1.8.4,2.0.0)",
+ org.objenesis;bundle-version="[1.0.0,2.0.0)",
+ org.hamcrest;bundle-version="[1.0.0,2.0.0)"
 Export-Package: org.eclipse.mylyn.context.tests;x-internal:=true,
  org.eclipse.mylyn.context.tests.support;x-internal:=true,
  org.eclipse.mylyn.context.tests.support.search;x-internal:=true
diff --git a/org.eclipse.mylyn.context.tests/src/org/eclipse/mylyn/context/tests/ContextExternalizerTest.java b/org.eclipse.mylyn.context.tests/src/org/eclipse/mylyn/context/tests/ContextExternalizerTest.java
index 4d6edfd..e5eb933 100644
--- a/org.eclipse.mylyn.context.tests/src/org/eclipse/mylyn/context/tests/ContextExternalizerTest.java
+++ b/org.eclipse.mylyn.context.tests/src/org/eclipse/mylyn/context/tests/ContextExternalizerTest.java
@@ -11,18 +11,25 @@
 
 package org.eclipse.mylyn.context.tests;
 
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.FileOutputStream;
+import java.io.InputStream;
+import java.util.Scanner;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipOutputStream;
 
 import org.eclipse.mylyn.commons.sdk.util.CommonTestUtil;
 import org.eclipse.mylyn.context.core.ContextCore;
+import org.eclipse.mylyn.context.core.IContextContributor;
 import org.eclipse.mylyn.context.core.IInteractionContext;
 import org.eclipse.mylyn.context.core.IInteractionContextScaling;
 import org.eclipse.mylyn.context.core.IInteractionElement;
 import org.eclipse.mylyn.context.core.IInteractionRelation;
-import org.eclipse.mylyn.context.sdk.util.AbstractContextTest;
 import org.eclipse.mylyn.context.tests.support.DomContextReader;
 import org.eclipse.mylyn.context.tests.support.DomContextWriter;
 import org.eclipse.mylyn.internal.context.core.ContextCorePlugin;
@@ -30,6 +37,7 @@ import org.eclipse.mylyn.internal.context.core.InteractionContext;
 import org.eclipse.mylyn.internal.context.core.InteractionContextExternalizer;
 import org.eclipse.mylyn.internal.context.core.InteractionContextManager;
 import org.eclipse.mylyn.internal.context.core.SaxContextReader;
+import org.eclipse.mylyn.monitor.core.InteractionEvent;
 
 /**
  * @author Mik Kersten
@@ -43,6 +51,8 @@ public class ContextExternalizerTest extends AbstractContextTest {
 
 	private IInteractionContextScaling scaling;
 
+	private File contextFile;
+
 	@Override
 	protected void setUp() throws Exception {
 		super.setUp();
@@ -53,6 +63,10 @@ public class ContextExternalizerTest extends AbstractContextTest {
 
 	@Override
 	protected void tearDown() throws Exception {
+		if (contextFile != null && contextFile.exists()) {
+			contextFile.delete();
+		}
+
 		super.tearDown();
 	}
 
@@ -297,4 +311,46 @@ public class ContextExternalizerTest extends AbstractContextTest {
 		assertNull(context);
 	}
 
+	public void testAddContextContributor() throws Exception {
+		InteractionContextExternalizer externalizer = new InteractionContextExternalizer();
+		ContextCorePlugin contextCorePlugin = ContextCorePlugin.getDefault();
+		IContextContributor contributor = mock(IContextContributor.class);
+		when(contributor.getDataAsStream(context)).thenReturn(null);
+
+		contextCorePlugin.addContextContributor(contributor);
+		assertEquals(1, contextCorePlugin.getContextContributor().size());
+		assertEquals(contributor, contextCorePlugin.getContextContributor().get(0));
+
+		externalizer.writeContext(context, mock(ZipOutputStream.class));
+		verify(contributor).getDataAsStream(context);
+
+		contextCorePlugin.removeContextContributor(contributor);
+		assertEquals(0, contextCorePlugin.getContextContributor().size());
+	}
+
+	public void testWriteAdditionalContextData() throws Exception {
+		InteractionContextExternalizer externalizer = new InteractionContextExternalizer();
+		IContextContributor contributor = mock(IContextContributor.class);
+		InteractionEvent event = mockNavigation("InteractionEvent");
+		context.parseEvent(event);
+
+		String testContributorId = "myContributor";
+		String testData = "important context information";
+		InputStream testStream = new ByteArrayInputStream(testData.getBytes());
+		when(contributor.getIdentifier()).thenReturn(testContributorId);
+		when(contributor.getDataAsStream(context)).thenReturn(testStream);
+		ContextCorePlugin.getDefault().addContextContributor(contributor);
+
+		contextFile = ContextCorePlugin.getContextStore().getFileForContext(context.getHandleIdentifier());
+
+		externalizer.writeContextToXml(context, contextFile);
+		InputStream resultStream = externalizer.getAdditionalInformation(contextFile, testContributorId);
+		assertNotNull(resultStream);
+		assertNull(externalizer.getAdditionalInformation(contextFile, "nonExistingContributor"));
+		assertEquals(testData, new Scanner(resultStream).useDelimiter("\\A").next());
+
+		resultStream = ContextCore.getContextManager().getAdditionalContextData(context, testContributorId);
+		assertNotNull(resultStream);
+		assertNull(externalizer.getAdditionalInformation(contextFile, "nonExistingContributor"));
+	}
 }