Bug 468030: [Papyrus Core] Papyrus DI Model should support the notion of Language

https://bugs.eclipse.org/bugs/show_bug.cgi?id=468030

Implement a Language Service for configuration of the Papyrus ModelSet to
support custom implementations of UML and other modeling languages.

Includes:

* language service providing languages before the ModelSet loads any resources
* hooks for languages to configure and unconfigure a ModelSet
* implementation of a language provider that maps applied profiles to languages
* addition of a profile index service that provides the URIs of profiles applied
  to model resources without having to load them in a resource set
* a stub of a UML-RT language with placeholder for configuration of the ModelSet
* a standard UML language
* implementation of the profile index service using an enhanced DecoratorModelIndex
  that now also index the normal profile applications in user models

Papyrus Service Registry changes:

* fix the explicit starting of lazy services
* new AbstractServiceUtils API for requesting optional or defaultable services

Also includes the very barest of JUnit tests covering:

* the new profile index service
* using the language service to query content-type-based languages
* UML languages:  UML models have the UML language, itself, and proper
  matching and installation of profile languages

Change-Id: I9d5175cfbefbe40864f04ea4215e18556e3739df
Reviewed-on: https://git.eclipse.org/r/49152
Tested-by: Hudson CI
Reviewed-by: Camille Letavernier <camille.letavernier@cea.fr>

19 files changed, 1482 insertions, 26 deletions

diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/META-INF/MANIFEST.MF b/plugins/infra/core/org.eclipse.papyrus.infra.core/META-INF/MANIFEST.MF
index 850c6ec0719..44505d47c1a 100644
--- a/plugins/infra/core/org.eclipse.papyrus.infra.core/META-INF/MANIFEST.MF
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/META-INF/MANIFEST.MF
@@ -8,6 +8,7 @@ Export-Package: org.eclipse.papyrus.infra.core,
  org.eclipse.papyrus.infra.core.extension,
  org.eclipse.papyrus.infra.core.extension.commands,
  org.eclipse.papyrus.infra.core.extension.diagrameditor,
+ org.eclipse.papyrus.infra.core.language,
  org.eclipse.papyrus.infra.core.lifecycleevents,
  org.eclipse.papyrus.infra.core.listenerservice,
  org.eclipse.papyrus.infra.core.markers,
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/plugin.xml b/plugins/infra/core/org.eclipse.papyrus.infra.core/plugin.xml
index 1ec4a12a9ec..7a1ae21bd95 100644
--- a/plugins/infra/core/org.eclipse.papyrus.infra.core/plugin.xml
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/plugin.xml
@@ -8,6 +8,7 @@
    <extension-point id="model" name="plugin.xml.ModelName" schema="schema/model.exsd"/>

    <extension-point id="transactionalEditingDomainProvider" name="transactionalEditingDomainProvider" schema="schema/transactionalEditingDomainProvider.exsd"/>

    <extension-point id="sashModelProvider" name="Sash Model Providers" schema="schema/sashModelProvider.exsd"/>

+   <extension-point id="language" name="Modeling Language" schema="schema/language.exsd"/>

    

    <extension

          point="org.eclipse.ui.menus">

@@ -394,5 +395,14 @@
                 type="org.eclipse.papyrus.infra.core.services.IService">

           </adapter>

        </factory>

+    </extension>

+    <extension

+          point="org.eclipse.papyrus.infra.core.service">

+       <service

+             classname="org.eclipse.papyrus.infra.core.internal.language.LanguageService"

+             id="org.eclipse.papyrus.infra.core.language.ILanguageService"

+             priority="10"

+             startKind="startup">

+       </service>

     </extension>
 </plugin>

diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/schema/language.exsd b/plugins/infra/core/org.eclipse.papyrus.infra.core/schema/language.exsd
new file mode 100644
index 00000000000..516be1d8310
--- /dev/null
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/schema/language.exsd
@@ -0,0 +1,219 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!-- Schema file written by PDE -->
+<schema targetNamespace="org.eclipse.papyrus.infra.core" xmlns="http://www.w3.org/2001/XMLSchema">
+<annotation>
+      <appInfo>
+         <meta.schema plugin="org.eclipse.papyrus.infra.core" id="language" name="Modeling Language"/>
+      </appInfo>
+      <documentation>
+         Registration of Modeling Languages in the Papyrus Language Service.
+      </documentation>
+   </annotation>
+
+   <element name="extension">
+      <annotation>
+         <appInfo>
+            <meta.element />
+         </appInfo>
+      </annotation>
+      <complexType>
+         <sequence>
+            <element ref="provider" minOccurs="1" maxOccurs="unbounded"/>
+         </sequence>
+         <attribute name="point" type="string" use="required">
+            <annotation>
+               <documentation>
+                  
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="id" type="string">
+            <annotation>
+               <documentation>
+                  
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="name" type="string">
+            <annotation>
+               <documentation>
+                  
+               </documentation>
+               <appInfo>
+                  <meta.attribute translatable="true"/>
+               </appInfo>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <element name="provider">
+      <annotation>
+         <documentation>
+            Registration of a Papryus modeling language provider.
+         </documentation>
+      </annotation>
+      <complexType>
+         <sequence>
+            <element ref="class" minOccurs="0" maxOccurs="1"/>
+            <choice minOccurs="0" maxOccurs="unbounded">
+               <element ref="content-type"/>
+               <element ref="language"/>
+            </choice>
+         </sequence>
+         <attribute name="class" type="string">
+            <annotation>
+               <documentation>
+                  The name of a language provider class.  If not specified, then nested elements are required to specify a generic provider that matches URIs to languages.
+The class may also be specified by the nested &lt;tt&gt;&amp;lt;class&amp;gt;&lt;/tt&gt; element, especially if it is parameterized.
+               </documentation>
+               <appInfo>
+                  <meta.attribute kind="java" basedOn=":org.eclipse.papyrus.infra.core.language.ILanguageProvider"/>
+               </appInfo>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <element name="content-type">
+      <annotation>
+         <documentation>
+            Matches languages by resource content type.
+Ignored if the &lt;tt&gt;class&lt;/tt&gt; attribute of the &lt;tt&gt;&amp;lt;provider&amp;gt;&lt;/tt&gt; element is specified.
+Required if the &lt;tt&gt;&amp;lt;language&amp;gt;&lt;/tt&gt; element is specified.
+         </documentation>
+      </annotation>
+      <complexType>
+         <attribute name="id" type="string" use="required">
+            <annotation>
+               <documentation>
+                  References a resource content type for which to provider a language.
+               </documentation>
+               <appInfo>
+                  <meta.attribute kind="identifier" basedOn="org.eclipse.core.contenttype.contentTypes/content-type/@id"/>
+               </appInfo>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <element name="language">
+      <annotation>
+         <documentation>
+            Specifies a language matched by resource content type.
+Ignored if the &lt;tt&gt;class&lt;/tt&gt; attribute or &lt;tt&gt;&amp;lt;implementation&amp;gt;&lt;/tt&gt; element of the &lt;tt&gt;&amp;lt;provider&amp;gt;&lt;/tt&gt; element is specified.
+Required if the &lt;tt&gt;&amp;lt;contentType&amp;gt;&lt;/tt&gt; element is specified.
+         </documentation>
+      </annotation>
+      <complexType>
+         <attribute name="class" type="string">
+            <annotation>
+               <documentation>
+                  The name of a language implementation class.  If not specified, then a default implementation is supplied based on the other attributes that simply does no ModelSet configuration.
+               </documentation>
+               <appInfo>
+                  <meta.attribute kind="java" basedOn=":org.eclipse.papyrus.infra.core.language.ILanguage"/>
+               </appInfo>
+            </annotation>
+         </attribute>
+         <attribute name="id" type="string" use="required">
+            <annotation>
+               <documentation>
+                  An unique identifier for the language.
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="version" type="string" use="required">
+            <annotation>
+               <documentation>
+                  The version number of the language.
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="name" type="string" use="required">
+            <annotation>
+               <documentation>
+                  The localized user-presentable name of the language.
+               </documentation>
+               <appInfo>
+                  <meta.attribute translatable="true"/>
+               </appInfo>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <element name="class">
+      <annotation>
+         <documentation>
+            Specification of a parameterized executable extension.  If specified, then the &lt;tt&gt;class&lt;/tt&gt; attribute is ignored.
+         </documentation>
+      </annotation>
+      <complexType>
+         <sequence>
+            <element ref="parameter" minOccurs="0" maxOccurs="unbounded"/>
+         </sequence>
+         <attribute name="class" type="string">
+            <annotation>
+               <documentation>
+                  The name of a language provider class.  Parameters may be specified to configure the instance as appropriate to its API specification.
+               </documentation>
+               <appInfo>
+                  <meta.attribute kind="java" basedOn=":org.eclipse.papyrus.infra.core.language.ILanguageProvider"/>
+               </appInfo>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <element name="parameter">
+      <annotation>
+         <documentation>
+            A name/value pair to configure an implementation of the language provider.
+         </documentation>
+      </annotation>
+      <complexType>
+         <attribute name="name" type="string" use="required">
+            <annotation>
+               <documentation>
+                  An unique parameter name, as specified by the API of the implementation class.
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="value" type="string" use="required">
+            <annotation>
+               <documentation>
+                  
+               </documentation>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <annotation>
+      <appInfo>
+         <meta.section type="since"/>
+      </appInfo>
+      <documentation>
+         1.1.0
+      </documentation>
+   </annotation>
+
+
+
+
+   <annotation>
+      <appInfo>
+         <meta.section type="copyright"/>
+      </appInfo>
+      <documentation>
+         Copyright (c) 2015 Christian W. Damus 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
+      </documentation>
+   </annotation>
+
+</schema>
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/editor/ModelSetServiceFactory.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/editor/ModelSetServiceFactory.java
index ae76099d3b4..185172c1f33 100644
--- a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/editor/ModelSetServiceFactory.java
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/editor/ModelSetServiceFactory.java
@@ -1,5 +1,5 @@
 /*****************************************************************************

- * Copyright (c) 2011, 2014 CEA LIST and others.

+ * Copyright (c) 2011, 2015 CEA LIST, Christian W. Damus, and others.

  *

  *

  * All rights reserved. This program and the accompanying materials

@@ -10,11 +10,13 @@
  * Contributors:

  *  CEA LIST - Initial API and implementation

  *  Christian W. Damus (CEA) - bug 431953 (pre-requisite refactoring of ModelSet service start-up)

+ *  Christian W. Damus - bug 468030

  *

  *****************************************************************************/

 package org.eclipse.papyrus.infra.core.editor;

 

 import org.eclipse.emf.ecore.resource.ResourceSet;

+import org.eclipse.papyrus.infra.core.language.ILanguageService;

 import org.eclipse.papyrus.infra.core.resource.ModelSet;

 import org.eclipse.papyrus.infra.core.services.IServiceFactory;

 import org.eclipse.papyrus.infra.core.services.ModelSetServiceAdapter;

@@ -46,15 +48,14 @@ public class ModelSetServiceFactory implements IServiceFactory {
 		this.serviceRegistry = servicesRegistry;

 	}

 

-	/**

-	 *

-	 * @see org.eclipse.papyrus.infra.core.services.IService#startService()

-	 *

-	 * @throws ServiceException

-	 */

 	@Override

 	public void startService() throws ServiceException {

-		// Pass

+		// If the language service is available (optional dependency), the ModelSet will want to use it, so start it

+		try {

+			serviceRegistry.startServicesByClassKeys(ILanguageService.class);

+		} catch (ServiceException e) {

+			// It's okay: the language service is optional

+		}

 	}

 

 	/**

diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/internal/language/DefaultLanguageProvider.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/internal/language/DefaultLanguageProvider.java
new file mode 100644
index 00000000000..11f745b52d1
--- /dev/null
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/internal/language/DefaultLanguageProvider.java
@@ -0,0 +1,203 @@
+/*****************************************************************************
+ * Copyright (c) 2015 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *   
+ *****************************************************************************/
+
+package org.eclipse.papyrus.infra.core.internal.language;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.eclipse.core.resources.IContainer;
+import org.eclipse.core.resources.IResource;
+import org.eclipse.core.resources.ResourcesPlugin;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IConfigurationElement;
+import org.eclipse.core.runtime.IPath;
+import org.eclipse.core.runtime.Path;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.runtime.content.IContentType;
+import org.eclipse.emf.common.util.URI;
+import org.eclipse.emf.ecore.resource.ContentHandler;
+import org.eclipse.emf.ecore.resource.URIConverter;
+import org.eclipse.papyrus.infra.core.Activator;
+import org.eclipse.papyrus.infra.core.language.ILanguage;
+import org.eclipse.papyrus.infra.core.language.ILanguageProvider;
+import org.eclipse.papyrus.infra.core.language.ILanguageService;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+
+/**
+ * A default language provider for extensions that simply declare content-type matches for languages.
+ */
+public class DefaultLanguageProvider implements ILanguageProvider {
+	private final Set<IContentType> contentTypes = Sets.newHashSet();
+
+	private final List<ILanguage> languages = Lists.newArrayList();
+
+	private List<LanguageProxy> languageProxies;
+
+	public DefaultLanguageProvider() {
+		super();
+	}
+
+	@Override
+	public synchronized Iterable<ILanguage> getLanguages(ILanguageService languageService, URI modelURI, boolean uriHasFileExtension) {
+		Set<URI> allURIs;
+
+		try {
+			allURIs = resolveURIs(modelURI, uriHasFileExtension);
+		} catch (CoreException e) {
+			Activator.log.log(e.getStatus());
+
+			// Can't match our content types against anything
+			return Collections.emptyList();
+		}
+
+		if (!matchContentType(allURIs)) {
+			return Collections.emptyList();
+		} else {
+			// If any of my content-types matches, then all of my languages are present
+			resolveProxies();
+			return Collections.unmodifiableList(languages);
+		}
+	}
+
+	void addContentType(String id) {
+		IContentType contentType = Platform.getContentTypeManager().getContentType(id);
+		if (contentType == null) {
+			Activator.log.warn("No such content-type in language provider extension: " + id); //$NON-NLS-1$
+		} else {
+			contentTypes.add(contentType);
+		}
+	}
+
+	synchronized void addLanguage(ILanguage language) {
+		this.languages.add(language);
+	}
+
+	synchronized void addLanguage(IConfigurationElement config, String attribute) {
+		if (languageProxies == null) {
+			languageProxies = Lists.newArrayList();
+		}
+
+		languageProxies.add(new LanguageProxy(config, attribute));
+	}
+
+	private void resolveProxies() {
+		if (languageProxies != null) {
+			try {
+				for (LanguageProxy next : languageProxies) {
+					ILanguage resolved = next.resolve();
+					if (resolved != null) {
+						addLanguage(resolved);
+					}
+				}
+			} finally {
+				languageProxies = null;
+			}
+		}
+	}
+
+	private Set<URI> resolveURIs(URI modelURI, boolean uriHasFileExtension) throws CoreException {
+		// If given an extension, just take that
+		if (uriHasFileExtension) {
+			return Collections.singleton(modelURI);
+		}
+
+		Set<URI> result = Sets.newHashSet();
+
+		if (modelURI.isPlatformResource()) {
+			String baseName = modelURI.lastSegment();
+			IPath path = new Path(modelURI.trimSegments(1).toPlatformString(true));
+			IContainer container = (path.segmentCount() > 1) ? ResourcesPlugin.getWorkspace().getRoot().getFolder(path) : ResourcesPlugin.getWorkspace().getRoot().getProject(path.lastSegment());
+			for (IResource next : container.members()) {
+				if (next.getType() == IResource.FILE) {
+					IPath nextPath = next.getFullPath();
+					String name = nextPath.removeFileExtension().lastSegment();
+					if (name.equals(baseName)) {
+						result.add(URI.createPlatformResourceURI(nextPath.toString(), true));
+					}
+				}
+			}
+		} else if (modelURI.isFile()) {
+			String baseName = modelURI.lastSegment();
+			File directory = new File(modelURI.trimSegments(1).toFileString());
+			for (File next : directory.listFiles()) {
+				if (next.isFile()) {
+					IPath nextPath = new Path(directory.getPath()).append(next.getName());
+					String name = nextPath.removeFileExtension().lastSegment();
+					if (name.equals(baseName)) {
+						result.add(URI.createPlatformResourceURI(nextPath.toString(), true));
+					}
+				}
+			}
+		}
+
+		return result;
+	}
+
+	private boolean matchContentType(Set<URI> uris) {
+		boolean result = false;
+
+		out: for (URI next : uris) {
+			try {
+				Map<String, ?> desc = URIConverter.INSTANCE.contentDescription(next, null);
+				String contentTypeID = (String) desc.get(ContentHandler.CONTENT_TYPE_PROPERTY);
+				if (contentTypeID != null) {
+					IContentType contentType = Platform.getContentTypeManager().getContentType(contentTypeID);
+					if (contentType != null) {
+						for (IContentType type : contentTypes) {
+							if (contentType.isKindOf(type)) {
+								result = true;
+								break out;
+							}
+						}
+					}
+				}
+			} catch (IOException e) {
+				// Not our content type, I guess
+			}
+		}
+
+		return result;
+	}
+
+	//
+	// Nested types
+	//
+
+	private static class LanguageProxy {
+		private final IConfigurationElement config;
+		private final String attribute;
+
+		LanguageProxy(IConfigurationElement config, String attribute) {
+			super();
+
+			this.config = config;
+			this.attribute = attribute;
+		}
+
+		ILanguage resolve() {
+			try {
+				return (ILanguage) config.createExecutableExtension(attribute);
+			} catch (Exception e) {
+				Activator.log.error("Failed to instantiate language in provider extension from contributor " + config.getContributor().getName(), e); //$NON-NLS-1$
+				return null;
+			}
+		}
+	}
+}
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/internal/language/LanguageProviderRegistry.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/internal/language/LanguageProviderRegistry.java
new file mode 100644
index 00000000000..ce61df60eb6
--- /dev/null
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/internal/language/LanguageProviderRegistry.java
@@ -0,0 +1,260 @@
+/*****************************************************************************
+ * Copyright (c) 2015 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *   
+ *****************************************************************************/
+
+package org.eclipse.papyrus.infra.core.internal.language;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IConfigurationElement;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.emf.common.util.URI;
+import org.eclipse.emf.ecore.plugin.RegistryReader;
+import org.eclipse.papyrus.infra.core.Activator;
+import org.eclipse.papyrus.infra.core.language.ILanguage;
+import org.eclipse.papyrus.infra.core.language.ILanguageProvider;
+import org.eclipse.papyrus.infra.core.language.ILanguageService;
+import org.eclipse.papyrus.infra.core.language.Language;
+import org.eclipse.papyrus.infra.core.language.Version;
+
+import com.google.common.base.Strings;
+import com.google.common.collect.Lists;
+
+/**
+ * A registry of contributed {@link ILanguageProvider} implementations plugged in on my extension point.
+ */
+public class LanguageProviderRegistry implements ILanguageProvider.Registry {
+
+	private static final String EXT_POINT = "language"; //$NON-NLS-1$
+
+	private static final ILanguageProvider NULL_PROVIDER = new ILanguageProvider() {
+
+		@Override
+		public Iterable<ILanguage> getLanguages(ILanguageService languageService, URI modelURI, boolean uriHasFileExtension) {
+			return Collections.emptyList();
+		}
+	};
+
+	private final List<ILanguageProvider> providers = Lists.newArrayListWithExpectedSize(2);
+
+	private boolean needPrune;
+
+	public LanguageProviderRegistry() {
+		super();
+
+		new MyRegistryReader().readRegistry();
+	}
+
+	/**
+	 * Prune out any null providers (failed to initialize) and replace
+	 * descriptors that have been instantiated by their instances, to avoid
+	 * delegation.
+	 */
+	private void prune() {
+		if (needPrune) {
+			needPrune = false;
+			for (ListIterator<ILanguageProvider> iter = providers.listIterator(); iter.hasNext();) {
+
+				ILanguageProvider next = iter.next();
+				if (next == NULL_PROVIDER) {
+					iter.remove(); // Don't need this, any more
+				} else if (next instanceof MyRegistryReader.Descriptor) {
+					MyRegistryReader.Descriptor desc = (MyRegistryReader.Descriptor) next;
+					if (desc.instance != null) {
+						iter.set(desc.instance);
+					}
+				}
+			}
+		}
+	}
+
+	@Override
+	public Collection<ILanguageProvider> getProviders() {
+		prune();
+		return Collections.unmodifiableCollection(providers);
+	}
+
+	private void removeProvider(String className) {
+		synchronized (providers) {
+			for (Iterator<ILanguageProvider> iter = providers.iterator(); iter.hasNext();) {
+
+				ILanguageProvider next = iter.next();
+				if (next instanceof MyRegistryReader.Descriptor) {
+					MyRegistryReader.Descriptor desc = (MyRegistryReader.Descriptor) next;
+					if (className.equals(desc.getClassName())) {
+						iter.remove();
+						break;
+					}
+				} else if (className.equals(next.getClass().getName())) {
+					iter.remove();
+					break;
+				}
+			}
+		}
+	}
+
+	//
+	// Nested types
+	//
+
+	private class MyRegistryReader extends RegistryReader {
+
+		private static final String A_CLASS = "class"; //$NON-NLS-1$
+
+		private static final String E_PROVIDER = "provider"; //$NON-NLS-1$
+
+		private static final String E_CONTENT_TYPE = "content-type"; //$NON-NLS-1$
+		private static final String E_LANGUAGE = "language"; //$NON-NLS-1$
+		private static final String A_ID = "id"; //$NON-NLS-1$
+		private static final String A_VERSION = "version"; //$NON-NLS-1$
+		private static final String A_NAME = "name"; //$NON-NLS-1$
+
+		private Descriptor currentDescriptor;
+
+		MyRegistryReader() {
+			super(Platform.getExtensionRegistry(), Activator.PLUGIN_ID, EXT_POINT);
+		}
+
+		@Override
+		protected boolean readElement(IConfigurationElement element, boolean add) {
+			return add ? handleAdd(element) : handleRemove(element);
+		}
+
+		private boolean handleAdd(IConfigurationElement element) {
+			boolean result = true;
+
+			if (E_PROVIDER.equals(element.getName())) {
+				currentDescriptor = new Descriptor(element, A_CLASS);
+				providers.add(currentDescriptor);
+			}
+
+			return result;
+		}
+
+		private boolean handleRemove(IConfigurationElement element) {
+			boolean result = true;
+
+			if (E_PROVIDER.equals(element.getName())) {
+				String className = getClassName(element, A_CLASS);
+				if (className != null) {
+					removeProvider(className);
+				}
+			}
+
+			return result;
+		}
+
+		String getClassName(IConfigurationElement provider, String attributeName) {
+			String result = provider.getAttribute(attributeName);
+			if (result == null) {
+				IConfigurationElement[] classes = provider.getChildren(attributeName);
+				if (classes.length > 0) { // Assume a single occurrence
+					result = classes[0].getAttribute("class"); //$NON-NLS-1$ It's always 'class' attribute of a nested element
+				}
+			}
+			return result;
+		}
+
+		private class Descriptor extends PluginClassDescriptor implements ILanguageProvider {
+
+			private ILanguageProvider instance;
+
+			Descriptor(IConfigurationElement element, String attributeName) {
+				super(element, attributeName);
+			}
+
+			String getClassName() {
+				return MyRegistryReader.this.getClassName(element, attributeName);
+			}
+
+			ILanguageProvider getInstance() {
+				if (instance == null) {
+					try {
+						String className = getClassName();
+						if (className == null) {
+							// It's the default implementation
+							instance = createDefaultProvider();
+						} else {
+							instance = (ILanguageProvider) createInstance();
+						}
+					} catch (Exception e) {
+						Activator.log.error("Failed to instantiate language provider extension.", e);
+						instance = NULL_PROVIDER;
+					}
+
+					needPrune = true;
+				}
+
+				return instance;
+			}
+
+			@Override
+			public Iterable<ILanguage> getLanguages(ILanguageService languageService, URI modelURI, boolean uriHasFileExtension) {
+				return getInstance().getLanguages(languageService, modelURI, uriHasFileExtension);
+			}
+
+			ILanguageProvider createDefaultProvider() throws CoreException {
+				DefaultLanguageProvider result = new DefaultLanguageProvider();
+
+				for (IConfigurationElement next : element.getChildren()) {
+					if (E_CONTENT_TYPE.equals(next.getName())) {
+						addContentType(result, next);
+					} else if (E_LANGUAGE.equals(next.getName())) {
+						addLanguage(result, next);
+					}
+				}
+
+				return result;
+			}
+
+			private void addContentType(DefaultLanguageProvider provider, IConfigurationElement contentType) {
+				String id = contentType.getAttribute(A_ID);
+				if (Strings.isNullOrEmpty(id)) {
+					logMissingAttribute(contentType, A_ID);
+				} else {
+					provider.addContentType(id);
+				}
+			}
+
+			private void addLanguage(DefaultLanguageProvider provider, IConfigurationElement language) throws CoreException {
+				String className = language.getAttribute(A_CLASS);
+				if (Strings.isNullOrEmpty(className)) {
+					className = Language.class.getName();
+				}
+
+				// Maybe the plug-in specifies the default Language class explicitly
+				if (!className.equals(Language.class.getName())) {
+					provider.addLanguage(language, A_CLASS);
+				} else {
+					String id = language.getAttribute(A_ID);
+					if (Strings.isNullOrEmpty(id)) {
+						logMissingAttribute(language, A_ID);
+					}
+					String version = language.getAttribute(A_VERSION);
+					if (Strings.isNullOrEmpty(version)) {
+						logMissingAttribute(language, A_VERSION);
+					}
+					String name = language.getAttribute(A_NAME);
+					if (Strings.isNullOrEmpty(name)) {
+						logMissingAttribute(language, A_NAME);
+					}
+					provider.addLanguage(new Language(id, new Version(version), name));
+				}
+			}
+		}
+	}
+}
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/internal/language/LanguageService.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/internal/language/LanguageService.java
new file mode 100644
index 00000000000..c8f91883549
--- /dev/null
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/internal/language/LanguageService.java
@@ -0,0 +1,110 @@
+/*****************************************************************************
+ * Copyright (c) 2015 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *   
+ *****************************************************************************/
+
+package org.eclipse.papyrus.infra.core.internal.language;
+
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+import org.eclipse.core.runtime.PlatformObject;
+import org.eclipse.emf.common.util.URI;
+import org.eclipse.papyrus.infra.core.language.ILanguage;
+import org.eclipse.papyrus.infra.core.language.ILanguageProvider;
+import org.eclipse.papyrus.infra.core.language.ILanguageService;
+import org.eclipse.papyrus.infra.core.services.IService;
+import org.eclipse.papyrus.infra.core.services.ServiceException;
+import org.eclipse.papyrus.infra.core.services.ServicesRegistry;
+import org.eclipse.papyrus.infra.core.utils.ServiceUtils;
+
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+
+/**
+ * The implementation of the Papyrus Modeling Language Service.
+ */
+public class LanguageService extends PlatformObject implements ILanguageService, IService {
+
+	private final CopyOnWriteArrayList<ILanguageProvider> languageProviders = Lists.newCopyOnWriteArrayList();
+
+	private ServicesRegistry registry;
+
+	public LanguageService() {
+		super();
+	}
+
+	@Override
+	public Set<ILanguage> getLanguages(URI modelURI, boolean uriHasFileExtension) {
+		Set<ILanguage> result = Sets.newHashSet();
+
+		for (ILanguageProvider next : languageProviders) {
+			Iterables.addAll(result, next.getLanguages(this, modelURI, uriHasFileExtension));
+		}
+
+		return result;
+	}
+
+	@Override
+	public void addLanguageProvider(ILanguageProvider provider) {
+		languageProviders.addIfAbsent(provider);
+	}
+
+	@Override
+	public void removeLanguageProvider(ILanguageProvider provider) {
+		if (provider != null) {
+			languageProviders.remove(provider);
+		}
+	}
+
+	//
+	// Adaptable API
+	//
+
+
+	/**
+	 * Adaptation to other services in the registry takes precedence over registered adapter factories.
+	 */
+	@Override
+	public <T> T getAdapter(Class<T> adapter) {
+		T result;
+
+		if (adapter.isInstance(registry)) {
+			result = adapter.cast(registry);
+		} else {
+			result = (registry == null) ? null : ServiceUtils.getInstance().getService(adapter, registry, null);
+		}
+
+		return (result != null) ? result : super.getAdapter(adapter);
+	}
+
+	//
+	// Service lifecycle API
+	//
+
+	@Override
+	public void init(ServicesRegistry servicesRegistry) throws ServiceException {
+		this.registry = servicesRegistry;
+	}
+
+	@Override
+	public void startService() throws ServiceException {
+		languageProviders.addAllAbsent(ILanguageProvider.Registry.INSTANCE.getProviders());
+	}
+
+	@Override
+	public void disposeService() throws ServiceException {
+		languageProviders.clear();
+		registry = null;
+	}
+
+}
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/ILanguage.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/ILanguage.java
new file mode 100644
index 00000000000..86ce58cfa22
--- /dev/null
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/ILanguage.java
@@ -0,0 +1,83 @@
+/*****************************************************************************
+ * Copyright (c) 2015 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *   
+ *****************************************************************************/
+
+package org.eclipse.papyrus.infra.core.language;
+
+import org.eclipse.papyrus.infra.core.resource.ModelSet;
+
+/**
+ * <p>
+ * Protocol for the definition of a <em>Modeling Language</em> as it is instantiated
+ * in a Papyrus model. Although one may distinguish between primary or core languages
+ * such as UML, Ecore, MOF, etc. as implemented by OMG metamodels and derivative
+ * languages such as UML profiles, specializations, or package merges, this API does
+ * not make any such distinction.
+ * </p>
+ * <p>
+ * Any number of languages may be instantiated in a Papyrus model, but as long as the
+ * {@linkplain ILanguageService Language Service} is present, there is always at least
+ * one language.
+ * </p>
+ */
+public interface ILanguage {
+
+	/**
+	 * Obtains an unique identifier of the language, irrespective of version.
+	 * 
+	 * @return
+	 */
+	String getID();
+
+	/**
+	 * Obtains the version of the language. All versions of a language have the same {@linkplain #getID() identifier}.
+	 * 
+	 * @return the version. Never {@code null}
+	 */
+	Version getVersion();
+
+	/**
+	 * Obtains the user-presentable (translated for the current locale) name of the language, not including any {@linkplain #getVersion() version number}.
+	 * 
+	 * @return my name. Never {@code null} or empty
+	 */
+	String getName();
+
+	/**
+	 * Installs me on a model-set. This performs whatever registrations, listener attachments, etc. that may be necessary
+	 * for the proper functioning of my language in the Papyrus context.
+	 * 
+	 * @param modelSet
+	 *            a model-set to configure
+	 */
+	void install(ModelSet modelSet);
+
+	/**
+	 * Uninstalls me from a model-set. This undoes whatever the {@linkplain #install(ModelSet) installation} did.
+	 * 
+	 * @param modelSet
+	 *            a model-set to unconfigure
+	 */
+	void uninstall(ModelSet modelSet);
+
+	/**
+	 * Two languages are equal if they have the same {@linkplain #getID() identifier} and {@linkplain #getVersion() version}.
+	 */
+	@Override
+	boolean equals(Object obj);
+
+	/**
+	 * Languages are hashed by {@linkplain #getID() identifier} and {@linkplain #getVersion() version}.
+	 */
+	@Override
+	int hashCode();
+}
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/ILanguageProvider.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/ILanguageProvider.java
new file mode 100644
index 00000000000..f1e2b3eacdd
--- /dev/null
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/ILanguageProvider.java
@@ -0,0 +1,53 @@
+/*****************************************************************************
+ * Copyright (c) 2015 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *   
+ *****************************************************************************/
+
+package org.eclipse.papyrus.infra.core.language;
+
+import java.util.Collection;
+
+import org.eclipse.emf.common.util.URI;
+import org.eclipse.papyrus.infra.core.internal.language.LanguageProviderRegistry;
+import org.eclipse.papyrus.infra.core.resource.ModelSet;
+
+/**
+ * A provider of {@link ILanguage}s to the {@linkplain ILanguageService service}.
+ * Providers may be registered dynamically using the {@linkplain ILanguageService#addLanguageProvider(ILanguageProvider) service API}
+ * or may be registered statically on the <tt>org.eclipse.papyrus.infra.core.language</tt> extension point.
+ */
+public interface ILanguageProvider {
+	/**
+	 * Queries the languages that are instantiated in the specified model resource.
+	 * 
+	 * @param languageService
+	 *            the language service that is requesting languages
+	 * @param modelURI
+	 *            the URI of a model resource for which the service wants to determine languages
+	 * @param uriHasFileExtension
+	 *            whether the {@code modelURI} has a file extension. For example, if the {@link ModelSet}
+	 *            is requesting languages, then the URI typically does not have an extension because a model-set comprising several
+	 *            resources that all have the same base file name
+	 * 
+	 * @return the languages instantiated in the specified resource. May be empty if this provider does not recognize any languages in the resource
+	 */
+	Iterable<ILanguage> getLanguages(ILanguageService languageService, URI modelURI, boolean uriHasFileExtension);
+
+	//
+	// Nested types
+	//
+
+	interface Registry {
+		Registry INSTANCE = new LanguageProviderRegistry();
+
+		Collection<ILanguageProvider> getProviders();
+	}
+}
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/ILanguageService.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/ILanguageService.java
new file mode 100644
index 00000000000..fbf34748f84
--- /dev/null
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/ILanguageService.java
@@ -0,0 +1,64 @@
+/*****************************************************************************
+ * Copyright (c) 2015 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *   
+ *****************************************************************************/
+
+package org.eclipse.papyrus.infra.core.language;
+
+import java.util.Set;
+
+import org.eclipse.core.runtime.IAdaptable;
+import org.eclipse.emf.common.util.URI;
+import org.eclipse.papyrus.infra.core.resource.ModelSet;
+
+/**
+ * <p>
+ * The Language Service provides information the {@linkplain ILanguage Modeling Languages} that are
+ * instantiated in a Papyrus model.
+ * </p>
+ * <p>
+ * In my capacity as an {@link IAdaptable}, I provide other services from the registry in which I
+ * am provided as adapters, in addition to whatever other adapters may be contributed for me.
+ * </p>
+ * 
+ * @see ILanguage
+ */
+public interface ILanguageService extends IAdaptable {
+	/**
+	 * Queries the languages that are instantiated in the specified model resource.
+	 * 
+	 * @param modelURI
+	 *            the URI of a model resource, such as might be used to load a {@link ModelSet}
+	 * @param uriHasFileExtension
+	 *            whether the {@code modelURI} has a file extension. For example, if the {@link ModelSet}
+	 *            is requesting languages, then the URI typically does not have an extension because a model-set comprising several
+	 *            resources that all have the same base file name
+	 * 
+	 * @return the languages instantiated in the specified resource
+	 */
+	Set<ILanguage> getLanguages(URI modelURI, boolean uriHasFileExtension);
+
+	/**
+	 * Registers a language {@code provider}. Has no effect if the given {@code provider} is already registered.
+	 * 
+	 * @param provider
+	 *            a language provider to add (may not be {@code null})
+	 */
+	void addLanguageProvider(ILanguageProvider provider);
+
+	/**
+	 * Unregisters a language {@code provider}. Has no effect if the given {@code provider} is not currently registered.
+	 * 
+	 * @param provider
+	 *            a language provider to remove (may be {@code null}, which has no effect)
+	 */
+	void removeLanguageProvider(ILanguageProvider provider);
+}
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/Language.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/Language.java
new file mode 100644
index 00000000000..280ba37eaee
--- /dev/null
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/Language.java
@@ -0,0 +1,101 @@
+/*****************************************************************************
+ * Copyright (c) 2015 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *   
+ *****************************************************************************/
+
+package org.eclipse.papyrus.infra.core.language;
+
+import org.eclipse.papyrus.infra.core.resource.ModelSet;
+
+/**
+ * Default implementation of a language. This implementation does nothing when {@linkplain #install(ModelSet) installed} on a model-set.
+ */
+public class Language implements ILanguage {
+	private final String id;
+	private final Version version;
+	private final String name;
+
+	public Language(String id, Version version, String name) {
+		super();
+
+		this.id = id;
+		this.version = version;
+		this.name = name;
+	}
+
+	@Override
+	public String getID() {
+		return id;
+	}
+
+	@Override
+	public Version getVersion() {
+		return version;
+	}
+
+	@Override
+	public String getName() {
+		return name;
+	}
+
+	@Override
+	public void install(ModelSet modelSet) {
+		// Pass
+	}
+
+	@Override
+	public void uninstall(ModelSet modelSet) {
+		// Pass
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + ((id == null) ? 0 : id.hashCode());
+		result = prime * result + ((version == null) ? 0 : version.hashCode());
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null) {
+			return false;
+		}
+		if (!(obj instanceof ILanguage)) {
+			return false;
+		}
+		ILanguage other = (ILanguage) obj;
+		if (id == null) {
+			if (other.getID() != null) {
+				return false;
+			}
+		} else if (!id.equals(other.getID())) {
+			return false;
+		}
+		if (version == null) {
+			if (other.getVersion() != null) {
+				return false;
+			}
+		} else if (!version.equals(other.getVersion())) {
+			return false;
+		}
+		return true;
+	}
+
+	@Override
+	public String toString() {
+		return String.format("%s version %s", getName(), getVersion()); //$NON-NLS-1$
+	}
+}
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/Version.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/Version.java
new file mode 100644
index 00000000000..9c232e30512
--- /dev/null
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/language/Version.java
@@ -0,0 +1,221 @@
+/*****************************************************************************
+ * Copyright (c) 2015 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *   
+ *****************************************************************************/
+
+package org.eclipse.papyrus.infra.core.language;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import com.google.common.base.Strings;
+
+/**
+ * A {@linkplain ILanguage language} version.
+ */
+public final class Version implements Comparable<Version> {
+	private final Pattern VERSION_PATTERN = Pattern.compile("^(-?\\d+)(\\.\\d+)?(\\.\\d+)?(\\.[A-Za-z0-9_+\\-]+)?$"); //$NON-NLS-1$
+
+	public static final Version ZERO = new Version(0, 0, 0, null);
+	public static final Version ONE = new Version(1, 0, 0, null);
+
+	private final int major;
+	private final int minor;
+	private final int service;
+	private final String qualifier;
+
+	/**
+	 * Initializes me.
+	 *
+	 * @param major
+	 *            my major increment. Others are zero
+	 */
+	public Version(int major) {
+		this(major, 0, 0, null);
+	}
+
+	/**
+	 * Initializes me.
+	 *
+	 * @param major
+	 *            my major increment
+	 * @param minor
+	 *            my minor increment. Must be a whole number
+	 * 
+	 * @throws IllegalArgumentException
+	 *             if the {@code minor} segment is negative
+	 */
+	public Version(int major, int minor) {
+		this(major, minor, 0, null);
+	}
+
+	/**
+	 * Initializes me.
+	 *
+	 * @param major
+	 *            my major increment
+	 * @param minor
+	 *            my minor increment. Must be a whole number
+	 * @param service
+	 *            my service increment. Must be a whole number
+	 * 
+	 * @throws IllegalArgumentException
+	 *             if any {@code minor}/{@code service} segment is negative
+	 */
+	public Version(int major, int minor, int service) {
+		this(major, minor, service, null);
+	}
+
+	/**
+	 * Initializes me.
+	 *
+	 * @param major
+	 *            my major increment
+	 * @param minor
+	 *            my minor increment. Must be a whole number
+	 * @param service
+	 *            my service increment. Must be a whole number
+	 * @param qualifier
+	 *            my qualifier (may be {@code null} if not needed, but not empty)
+	 * 
+	 * @throws IllegalArgumentException
+	 *             if any {@code minor}/{@code service} segment is negative or if the qualifier is the empty string
+	 */
+	public Version(int major, int minor, int service, String qualifier) {
+		super();
+
+		if (minor < 0) {
+			throw new IllegalArgumentException("Negative minor segment"); //$NON-NLS-1$
+		}
+		if (service < 0) {
+			throw new IllegalArgumentException("Negative service segment"); //$NON-NLS-1$
+		}
+		if ("".equals(qualifier)) { //$NON-NLS-1$
+			throw new IllegalArgumentException("Empty qualifier; should be null"); //$NON-NLS-1$
+		}
+
+		this.major = major;
+		this.minor = minor;
+		this.service = service;
+		this.qualifier = qualifier;
+	}
+
+	/**
+	 * Initializes me from my string representation.
+	 *
+	 * @param versionSpec
+	 *            my string representation
+	 * 
+	 * @throws IllegalArgumentException
+	 *             if the string representation has errors in any segment
+	 */
+	public Version(String versionSpec) {
+		super();
+
+		Matcher m = VERSION_PATTERN.matcher(versionSpec);
+		if (!m.matches()) {
+			throw new IllegalArgumentException("Invalid version specification: " + versionSpec); //$NON-NLS-1$
+		}
+
+		this.major = Integer.parseInt(m.group(1));
+		this.minor = m.group(2) == null ? 0 : Integer.parseInt(m.group(2).substring(1));
+		this.service = m.group(3) == null ? 0 : Integer.parseInt(m.group(3).substring(1));
+		this.qualifier = m.group(3) == null ? null : m.group(3).substring(1);
+	}
+
+	public int major() {
+		return major;
+	}
+
+	public int minor() {
+		return minor;
+	}
+
+	public int service() {
+		return service;
+	}
+
+	public String qualifier() {
+		return qualifier;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + major;
+		result = prime * result + minor;
+		result = prime * result + ((qualifier == null) ? 0 : qualifier.hashCode());
+		result = prime * result + service;
+		return result;
+	}
+
+	@Override
+	public String toString() {
+		return (qualifier == null)
+				? String.format("%s.%s.%s", major, minor, service) //$NON-NLS-1$
+				: String.format("%s.%s.%s.%s", major, minor, service, qualifier); //$NON-NLS-1$
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null) {
+			return false;
+		}
+		if (!(obj instanceof Version)) {
+			return false;
+		}
+		Version other = (Version) obj;
+		if (major != other.major) {
+			return false;
+		}
+		if (minor != other.minor) {
+			return false;
+		}
+		if (qualifier == null) {
+			if (other.qualifier != null) {
+				return false;
+			}
+		} else if (!qualifier.equals(other.qualifier)) {
+			return false;
+		}
+		if (service != other.service) {
+			return false;
+		}
+		return true;
+	}
+
+	@Override
+	public int compareTo(Version o) {
+		int result = o.major - this.major;
+		if (result == 0) {
+			result = o.minor - this.minor;
+			if (result == 0) {
+				result = o.service - this.service;
+				if (result == 0) {
+					result = Strings.nullToEmpty(o.qualifier).compareTo(Strings.nullToEmpty(this.qualifier));
+				}
+			}
+		}
+		return result;
+	}
+
+	public static org.osgi.framework.Version toOSGI(Version version) {
+		return new org.osgi.framework.Version(version.major, version.minor, version.service, version.qualifier);
+	}
+
+	public static Version fromOSGI(org.osgi.framework.Version version) {
+		return new Version(version.getMajor(), version.getMinor(), version.getMicro(), Strings.emptyToNull(version.getQualifier()));
+	}
+}
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/resource/ModelSet.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/resource/ModelSet.java
index a69a10ddc4a..50d98d220ea 100644
--- a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/resource/ModelSet.java
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/resource/ModelSet.java
@@ -20,6 +20,7 @@
  *  Gabriel Pascual (ALL4TEC) gabriel.pascual@all4tec.net - Bug 436952
  *  Gabriel Pascual (ALL4TEC) gabriel.pascual@all4tec.net - Bug 436998
  *  Christian W. Damus - bug 436998
+ *  Christian W. Damus - bug 468030
  *
  *****************************************************************************/
 package org.eclipse.papyrus.infra.core.resource;
@@ -61,10 +62,15 @@ import org.eclipse.emf.edit.domain.EditingDomain;
 import org.eclipse.emf.transaction.TransactionalEditingDomain;
 import org.eclipse.emf.transaction.impl.EditingDomainManager;
 import org.eclipse.papyrus.infra.core.Activator;
+import org.eclipse.papyrus.infra.core.editor.ModelSetServiceFactory;
+import org.eclipse.papyrus.infra.core.language.ILanguage;
+import org.eclipse.papyrus.infra.core.language.ILanguageService;
 import org.eclipse.papyrus.infra.core.resource.additional.AdditionalResourcesModel;
+import org.eclipse.papyrus.infra.core.utils.ServiceUtils;
 import org.eclipse.papyrus.infra.tools.util.PlatformHelper;
 
 import com.google.common.base.Optional;
+import com.google.common.collect.Lists;
 
 /**
  * This class is used to manage a set of {@link IModel}.
@@ -128,7 +134,7 @@ public class ModelSet extends ResourceSetImpl {
 	/** map of resource loaded in the resource set, with resource as the key and a boolean indicating if the resource is loaded or not has the valuer */
 	protected Map<Resource, Boolean> resourcesToLoadState = new HashMap<Resource, Boolean>();
 
-
+	private List<ILanguage> languages;
 
 	/**
 	 *
@@ -565,6 +571,8 @@ public class ModelSet extends ResourceSetImpl {
 		// Get the file name, without extension.
 		uriWithoutExtension = uri.trimFileExtension();
 
+		installLanguages();
+
 		ModelMultiException exceptions = null;
 		List<IModel> orderedModelsForLoading = getOrderedModelsForLoading();
 
@@ -995,6 +1003,8 @@ public class ModelSet extends ResourceSetImpl {
 			iter.remove();
 		}
 
+		uninstallLanguages();
+
 		// Clear the package registry (it may contain dynamic profile EPackages that we don't
 		// want to leak in BasicExtendedMetaData instances attached to static EPackages)
 		// Works around EMF bug 433108
@@ -1258,5 +1268,32 @@ public class ModelSet extends ResourceSetImpl {
 		return null;
 	}
 
+	protected void installLanguages() {
+		ILanguageService languageService = ServiceUtils.getInstance().getService(ILanguageService.class, ModelSetServiceFactory.getServiceRegistry(this), null);
+		if (languageService != null) {
+			languages = Lists.newArrayList(languageService.getLanguages(getURIWithoutExtension(), false));
 
+			for (ILanguage next : languages) {
+				try {
+					next.install(this);
+				} catch (Exception e) {
+					Activator.log.error("Uncaught exception in installation of language " + next, e); //$NON-NLS-1$
+				}
+			}
+		}
+	}
+
+	protected void uninstallLanguages() {
+		if (languages != null) {
+			for (ILanguage next : Lists.reverse(languages)) {
+				try {
+					next.uninstall(this);
+				} catch (Exception e) {
+					Activator.log.error("Uncaught exception in uninstallation of language " + next, e); //$NON-NLS-1$
+				}
+			}
+
+			languages.clear();
+		}
+	}
 }
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/BadStateException.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/BadStateException.java
index 1a7aa023923..fbcfe0b4402 100644
--- a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/BadStateException.java
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/BadStateException.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2011, 2014 LIFL and others.
+ * Copyright (c) 2011, 2015 LIFL, Christian W. Damus, and others.
  *
  *
  * All rights reserved. This program and the accompanying materials
@@ -9,6 +9,7 @@
  *
  * Contributors:
  *  LIFL - Initial API and implementation
+ *  Christian W. Damus - bug 468030
  *
  *****************************************************************************/
 package org.eclipse.papyrus.infra.core.services;
@@ -41,7 +42,7 @@ public class BadStateException extends ServiceException {
 	 * @param serviceDescriptor
 	 */
 	public BadStateException(String text, ServiceState state, ServiceDescriptor descriptor) {
-		super(text + " (Service= '" + descriptor.getKey() + ", state= " + state + ")");
+		super(text + " (Service= '" + descriptor.getKey() + "', state= " + state + ")");
 	}
 
 }
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServiceException.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServiceException.java
index f8c749a8f13..1ec8d111ec0 100644
--- a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServiceException.java
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServiceException.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2011, 2014 LIFL and others.
+ * Copyright (c) 2011, 2015 LIFL, Christian W. Damus, and others.
  *
  *
  * All rights reserved. This program and the accompanying materials
@@ -9,6 +9,7 @@
  *
  * Contributors:
  *  LIFL - Initial API and implementation
+ *  Christian W. Damus - bug 468030
  *
  *****************************************************************************/
 package org.eclipse.papyrus.infra.core.services;
@@ -30,7 +31,7 @@ public class ServiceException extends Exception {
 	 * Constructor.
 	 */
 	public ServiceException() {
-		// TODO Auto-generated constructor stub
+		super();
 	}
 
 	/**
@@ -40,7 +41,6 @@ public class ServiceException extends Exception {
 	 */
 	public ServiceException(String message) {
 		super(message);
-		// TODO Auto-generated constructor stub
 	}
 
 	/**
@@ -50,7 +50,6 @@ public class ServiceException extends Exception {
 	 */
 	public ServiceException(Throwable cause) {
 		super(cause);
-		// TODO Auto-generated constructor stub
 	}
 
 	/**
@@ -61,7 +60,35 @@ public class ServiceException extends Exception {
 	 */
 	public ServiceException(String message, Throwable cause) {
 		super(message, cause);
-		// TODO Auto-generated constructor stub
 	}
 
+	public ServiceException chain(Throwable next) {
+		return (next == null) ? this : new ServiceMultiException().chain(next);
+	}
+
+	public ServiceException chain(String identifier, Throwable next) {
+		return (next == null) ? this : new ServiceMultiException().chain(identifier, next);
+	}
+
+	public static ServiceException chain(ServiceException serviceException, Throwable next) {
+		if (serviceException != null) {
+			return serviceException.chain(next);
+		} else if (next instanceof ServiceException) {
+			return (ServiceException) next;
+		} else if (next != null) {
+			return new ServiceMultiException().chain(next);
+		} else {
+			return serviceException;
+		}
+	}
+
+	public static ServiceException chain(ServiceException serviceException, String identifier, Throwable next) {
+		if (serviceException != null) {
+			return serviceException.chain(identifier, next);
+		} else if (next != null) {
+			return new ServiceMultiException().chain(identifier, next);
+		} else {
+			return serviceException;
+		}
+	}
 }
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServiceMultiException.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServiceMultiException.java
index 3484f6d98d5..3a6f7ae2369 100644
--- a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServiceMultiException.java
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServiceMultiException.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2011, 2014 LIFL and others.
+ * Copyright (c) 2011, 2015 LIFL, Christian W. Damus, and others.
  *
  *
  * All rights reserved. This program and the accompanying materials
@@ -9,6 +9,7 @@
  *
  * Contributors:
  *  LIFL - Initial API and implementation
+ *  Christian W. Damus - bug 468030
  *
  *****************************************************************************/
 package org.eclipse.papyrus.infra.core.services;
@@ -149,4 +150,21 @@ public class ServiceMultiException extends ServiceException {
 		serviceIdentifiers.addAll(serviceIdentifiers);
 	}
 
+	@Override
+	public ServiceException chain(Throwable next) {
+		if (next instanceof ServiceMultiException) {
+			addAll((ServiceMultiException) next);
+		} else if (next != null) {
+			addException(next);
+		}
+		return this;
+	}
+
+	@Override
+	public ServiceException chain(String identifier, Throwable next) {
+		if (next != null) {
+			addException(identifier, next);
+		}
+		return this;
+	}
 }
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServicesRegistry.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServicesRegistry.java
index 695d89c579a..13601f8708c 100644
--- a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServicesRegistry.java
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/ServicesRegistry.java
@@ -1,5 +1,5 @@
 /*****************************************************************************

- * Copyright (c) 2011, 2014 LIFL, CEA, and others.

+ * Copyright (c) 2011, 2015 LIFL, CEA, Christian W. Damus, and others.

  *

  * All rights reserved. This program and the accompanying materials

  * are made available under the terms of the Eclipse Public License v1.0

@@ -9,6 +9,7 @@
  * Contributors:

  *  LIFL - Initial API and implementation

  *  Christian W. Damus (CEA) - bug 431953 (fix start-up of selective services to require only their dependencies)

+ *  Christian W. Damus - bug 468030

  */

 package org.eclipse.papyrus.infra.core.services;

 

@@ -628,14 +629,13 @@ public class ServicesRegistry {
 		}

 		// Detect cycles

 		checkCycle(roots, map);

-		// Retain only services with startupkind == START and state ==

-		// REGISTERED

-		roots = retainsToStartServices(roots);

+		// Retain only services with state == REGISTERED

+		roots = retainUnstartedServices(roots);

 		//

 		List<ServiceStartupEntry> toStart = buildTopologicalListOfServicesToStart(roots, map);

 

 		// Remove already started services

-		toStart = retainsToStartServices(toStart);

+		toStart = retainUnstartedServices(toStart);

 

 		// if( log.isLoggable(Level.FINE))

 		// {

@@ -769,6 +769,24 @@ public class ServicesRegistry {
 	}

 

 	/**

+	 * Retains the services that are not yet started. Retains only services with state == REGISTERED

+	 *

+	 * @param services

+	 *            Collection to filter

+	 * @return a new Collection containing the registered services

+	 */

+	private List<ServiceStartupEntry> retainUnstartedServices(Collection<ServiceStartupEntry> services) {

+		List<ServiceStartupEntry> result = new ArrayList<ServiceStartupEntry>(services.size());

+		for (ServiceStartupEntry service : services) {

+			if (service.getState() == ServiceState.registered) {

+				result.add(service);

+			}

+		}

+

+		return result;

+	}

+

+	/**

 	 * Check for cycles. Throws an exception if a cycle is discovered. Each root

 	 * is checked to see if it contains a cycle.

 	 *

diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/internal/LazyStartupEntry.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/internal/LazyStartupEntry.java
index a8df83e7159..708cd8b5dc8 100644
--- a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/internal/LazyStartupEntry.java
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/services/internal/LazyStartupEntry.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) CEA LIST.
+ * Copyright (c) CEA LIST, Christian W. Damus, and others.
  *
  *
  * All rights reserved. This program and the accompanying materials
@@ -9,10 +9,12 @@
  *
  * Contributors:
  *  Cedric Dumoulin  Cedric.dumoulin@lifl.fr - Initial API and implementation
+ *  Christian W. Damus - bug 468030
  *
  *****************************************************************************/
 package org.eclipse.papyrus.infra.core.services.internal;
 
+import org.eclipse.papyrus.infra.core.Activator;
 import org.eclipse.papyrus.infra.core.services.IService;
 import org.eclipse.papyrus.infra.core.services.ServiceException;
 import org.eclipse.papyrus.infra.core.services.ServiceState;
@@ -57,6 +59,7 @@ public class LazyStartupEntry extends ServiceStartupEntry {
 				serviceEntry.startService();
 			} catch (Exception e) {
 				// There was an error. The service is in error
+				Activator.log.error("Failed to start lazy service: " + getDescriptor().getKey(), e); //$NON-NLS-1$
 				serviceEntry = new ErrorServiceTypeEntry(serviceEntry.getDescriptor());
 			}
 		}
diff --git a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/utils/AbstractServiceUtils.java b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/utils/AbstractServiceUtils.java
index 6390ec7d546..2ce85f89fc6 100644
--- a/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/utils/AbstractServiceUtils.java
+++ b/plugins/infra/core/org.eclipse.papyrus.infra.core/src/org/eclipse/papyrus/infra/core/utils/AbstractServiceUtils.java
@@ -1,5 +1,5 @@
 /*****************************************************************************

- * Copyright (c) 2010 LIFL & CEA LIST.

+ * Copyright (c) 2010, 2015 LIFL & CEA LIST, Christian W. Damus, and others.

  *

  *

  * All rights reserved. This program and the accompanying materials

@@ -9,6 +9,7 @@
  *

  * Contributors:

  *  Cedric Dumoulin (LIFL) cedric.dumoulin@lifl.fr - Initial API and implementation

+ *  Christian W. Damus - bug 468030

  *

  *****************************************************************************/

 

@@ -143,7 +144,7 @@ public abstract class AbstractServiceUtils<T> {
 	 * @param from

 	 *            The context from which the service should be retrieved

 	 * @return

-	 *         The implementation of the requested service

+	 * 		The implementation of the requested service

 	 * @throws ServiceException

 	 *             If an error occurs (e.g. cannot find the ServicesRegistry or the Service)

 	 *

@@ -160,7 +161,7 @@ public abstract class AbstractServiceUtils<T> {
 	 * @param from

 	 *            The context from which the service should be retrieved

 	 * @return

-	 *         The implementation of the requested service

+	 * 		The implementation of the requested service

 	 * @throws ServiceException

 	 *             If an error occurs (e.g. cannot find the ServicesRegistry or the Service)

 	 *

@@ -168,4 +169,29 @@ public abstract class AbstractServiceUtils<T> {
 	public Object getService(Object service, T from) throws ServiceException {

 		return getServiceRegistry(from).getService(service);

 	}

+

+	/**

+	 * Returns an implementation of the requested <em>optional</em> service, from the specified context, if it is available.

+	 *

+	 * @param service

+	 *            The service for which an implementation is requested

+	 * @param from

+	 *            The context from which the service should be retrieved

+	 * @param defaultImpl

+	 *            A default implementation of the requested service API to return if none is available in the registry

+	 *            or if the registered implementation could not be properly initialized. May be {@code null} if the

+	 *            service is <em>optional</em>

+	 * 

+	 * @return

+	 * 		The implementation of the requested service, or the {@code defaultImpl}

+	 */

+	public <S> S getService(Class<S> service, T from, S defaultImpl) {

+		try {

+			// Don't even attempt to get a registry from a null context

+			return (from == null) ? defaultImpl : getServiceRegistry(from).getService(service);

+		} catch (ServiceException e) {

+			// That's OK. It's optional and we have a default

+			return defaultImpl;

+		}

+	}

 }