[514682] Add extension point to contribute meta-data to EPackages/metamodels

Bug: 514682
Change-Id: Ia4b8a5668bd4fb7952ef6f18b4b4da2935805489
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>

11 files changed, 482 insertions, 9 deletions

diff --git a/plugins/org.eclipse.sirius.common/META-INF/MANIFEST.MF b/plugins/org.eclipse.sirius.common/META-INF/MANIFEST.MF
index 5675897af5..7c81095066 100644
--- a/plugins/org.eclipse.sirius.common/META-INF/MANIFEST.MF
+++ b/plugins/org.eclipse.sirius.common/META-INF/MANIFEST.MF
@@ -10,6 +10,7 @@ Require-Bundle: org.eclipse.sirius.ecore.extender;bundle-version="2.0.0",
 Export-Package: org.eclipse.sirius.common.tools;version="3.0.0",
  org.eclipse.sirius.common.tools.api.constant;version="2.0.4",
  org.eclipse.sirius.common.tools.api.contentassist;version="2.1.0",
+ org.eclipse.sirius.common.tools.api.ecore;version="5.0.0",
  org.eclipse.sirius.common.tools.api.editing;version="2.0.4",
  org.eclipse.sirius.common.tools.api.find;version="3.0.0",
  org.eclipse.sirius.common.tools.api.interpreter;version="3.2.0",
diff --git a/plugins/org.eclipse.sirius.common/plugin.properties b/plugins/org.eclipse.sirius.common/plugin.properties
index 02606ecdab..ce3c217b70 100644
--- a/plugins/org.eclipse.sirius.common/plugin.properties
+++ b/plugins/org.eclipse.sirius.common/plugin.properties
@@ -19,6 +19,7 @@ extension-point.expressionInterpreter.name = org.eclipse.sirius.common.expressio
 extension-point.fileModificationValidator.name = File Modification Validator
 extension-point.proposalProvider.name = org.eclipse.sirius.common.proposalProvider
 extension-point.resourceSetFactory.name = org.eclipse.sirius.common.resourceSetFactory
+extension-point.package_meta_data.name=org.eclipse.sirius.common.package_meta_data
 
 BundleClassLoading_ignoredEPackageDeclaration = An EPackage declaration in project {0} has been ignored because of missing informations.
 ClassLoadingService_multipleOverridesDetected = Several overrides are contributed for the class loading override, {0} will be ignored
diff --git a/plugins/org.eclipse.sirius.common/plugin.xml b/plugins/org.eclipse.sirius.common/plugin.xml
index ea325b0acf..f273e12f15 100644
--- a/plugins/org.eclipse.sirius.common/plugin.xml
+++ b/plugins/org.eclipse.sirius.common/plugin.xml
@@ -20,6 +20,7 @@
   <extension-point id="fileModificationValidator" name="%extension-point.fileModificationValidator.name" schema="schema/fileModificationValidator.exsd"/>
   <extension-point id="resourceSetFactory" name="%extension-point.resourceSetFactory.name" schema="schema/resourceSetFactory.exsd"/>
   <extension-point id="classloading_override" name="%extension-point.classloading_override.name" schema="schema/classloading_override.exsd"/>
+  <extension-point id="package_meta_data" name="%extension-point.package_meta_data.name" schema="schema/package_meta_data.exsd"/>
   
   <extension id="org.eclipse.sirius.common.variableInterpreter" point="org.eclipse.sirius.common.expressionInterpreter">
     <expressionInterpreterProvider interpreterProviderClass="org.eclipse.sirius.common.tools.internal.interpreter.VariableInterpreter" />
diff --git a/plugins/org.eclipse.sirius.common/plugin_fr.properties b/plugins/org.eclipse.sirius.common/plugin_fr.properties
index c7b63beb4f..b6148ceef6 100644
--- a/plugins/org.eclipse.sirius.common/plugin_fr.properties
+++ b/plugins/org.eclipse.sirius.common/plugin_fr.properties
@@ -19,6 +19,7 @@ extension-point.expressionInterpreter.name = org.eclipse.sirius.common.expressio
 extension-point.fileModificationValidator.name = File Modification Validator
 extension-point.proposalProvider.name = org.eclipse.sirius.common.proposalProvider
 extension-point.resourceSetFactory.name = org.eclipse.sirius.common.resourceSetFactory
+extension-point.package_meta_data.name=org.eclipse.sirius.common.package_meta_data
 
 BundleClassLoading_ignoredEPackageDeclaration = An EPackage declaration in project {0} has been ignored because of missing informations.
 ClassLoadingService_multipleOverridesDetected = Several overrides are contributed for the class loading override, {0} will be ignored
diff --git a/plugins/org.eclipse.sirius.common/schema/package_meta_data.exsd b/plugins/org.eclipse.sirius.common/schema/package_meta_data.exsd
new file mode 100644
index 0000000000..7fb42f59a2
--- /dev/null
+++ b/plugins/org.eclipse.sirius.common/schema/package_meta_data.exsd
@@ -0,0 +1,116 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!-- Schema file written by PDE -->
+<schema targetNamespace="org.eclipse.sirius.common" xmlns="http://www.w3.org/2001/XMLSchema">
+<annotation>
+      <appInfo>
+         <meta.schema plugin="org.eclipse.sirius.common" id="package_meta_data" name="EPackage Meta Data"/>
+      </appInfo>
+      <documentation>
+         This extension point can be used to associate extra meta-data (label, documentation, preferred root element) to an EMF EPackage.
+      </documentation>
+   </annotation>
+
+   <element name="extension">
+      <annotation>
+         <appInfo>
+            <meta.element />
+         </appInfo>
+      </annotation>
+      <complexType>
+         <sequence minOccurs="0" maxOccurs="unbounded">
+            <element ref="ePackageMetaData"/>
+         </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>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <element name="ePackageMetaData">
+      <complexType>
+         <sequence minOccurs="0" maxOccurs="unbounded">
+            <element ref="suggestedRoot"/>
+         </sequence>
+         <attribute name="nsURI" type="string" use="required">
+            <annotation>
+               <documentation>
+                  The nsURI of the EPackage this applies to.
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="displayName" type="string">
+            <annotation>
+               <documentation>
+                  A human readable label to associate to the EPackage.
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="documentation" type="string">
+            <annotation>
+               <documentation>
+                  Documentation to associate to the EPackage. Will be rendered as HTML.
+               </documentation>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <element name="suggestedRoot">
+      <complexType>
+         <attribute name="className" type="string">
+            <annotation>
+               <documentation>
+                  The name of an EClass which is a good candidate for being the root element of a model. The named class must be contained directly in the EPackage.
+               </documentation>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <annotation>
+      <appInfo>
+         <meta.section type="since"/>
+      </appInfo>
+      <documentation>
+         5.0.0
+      </documentation>
+   </annotation>
+
+
+
+
+   <annotation>
+      <appInfo>
+         <meta.section type="copyright"/>
+      </appInfo>
+      <documentation>
+         Copyright (c) 2017 Obeo.
+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:
+    Obeo - initial API and implementation
+      </documentation>
+   </annotation>
+
+</schema>
diff --git a/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/DslCommonPlugin.java b/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/DslCommonPlugin.java
index e377307a93..b9208f2280 100644
--- a/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/DslCommonPlugin.java
+++ b/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/DslCommonPlugin.java
@@ -16,12 +16,15 @@ import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.emf.common.EMFPlugin;
 import org.eclipse.emf.common.util.ResourceLocator;
+import org.eclipse.sirius.common.tools.api.ecore.EPackageMetaData;
 import org.eclipse.sirius.common.tools.api.editing.EditingDomainFactoryRegistry;
 import org.eclipse.sirius.common.tools.api.profiler.TimeProfiler;
 import org.eclipse.sirius.common.tools.api.profiler.TimeProfiler2;
 import org.eclipse.sirius.common.tools.internal.assist.ProposalProviderRegistry;
 import org.eclipse.sirius.common.tools.internal.assist.ProposalProviderRegistryListener;
 import org.eclipse.sirius.common.tools.internal.ecore.DynamicPackageRegistryReader;
+import org.eclipse.sirius.common.tools.internal.ecore.EPackageMetaDataRegistry;
+import org.eclipse.sirius.common.tools.internal.ecore.EPackageMetaDataRegistryReader;
 import org.eclipse.sirius.common.tools.internal.editing.EditingDomainFactoryRegistryListener;
 import org.osgi.framework.BundleContext;
 
@@ -34,7 +37,7 @@ public class DslCommonPlugin extends EMFPlugin {
 
     /** The plugin id. */
     public static final String PLUGIN_ID = "org.eclipse.sirius.common"; //$NON-NLS-1$
-    
+
     /** Keep track of the singleton.. */
     public static final DslCommonPlugin INSTANCE = new DslCommonPlugin();
 
@@ -43,6 +46,8 @@ public class DslCommonPlugin extends EMFPlugin {
 
     private static Implementation plugin;
 
+    private final EPackageMetaDataRegistry metaDataRegistry = new EPackageMetaDataRegistry();
+
     /**
      * The constructor.
      */
@@ -56,6 +61,17 @@ public class DslCommonPlugin extends EMFPlugin {
     }
 
     /**
+     * Returns tha extra meta-data associated to a given EPackage.
+     * 
+     * @param nsURI
+     *            the nsURI of the EPackage.
+     * @return extra meta-data associated to the EPackage.
+     */
+    public EPackageMetaData getEPackageMetaData(String nsURI) {
+        return metaDataRegistry.getExtraData(nsURI);
+    }
+
+    /**
      * Returns the singleton instance of the Eclipse plugin.
      * 
      * @return the singleton instance.
@@ -70,18 +86,21 @@ public class DslCommonPlugin extends EMFPlugin {
     public static class Implementation extends EclipsePlugin {
 
         /**
-         * The registry listener that will be used to listen to extension
-         * changes.
+         * The registry listener that will be used to listen to extension changes.
          */
         private EditingDomainFactoryRegistryListener editingDomainFactoryRegistryListener = new EditingDomainFactoryRegistryListener();
 
         /**
-         * The registry listener that will be used to react to changes against
-         * the proposal providers extension point.
+         * The registry listener that will be used to react to changes against the proposal providers extension point.
          */
         private final ProposalProviderRegistryListener proposalProviderRegistryListener = new ProposalProviderRegistryListener();
 
         /**
+         * The registry of known EPackageMetaData.
+         */
+        private EPackageMetaDataRegistryReader packageMetaDataRegistryReader;
+
+        /**
          * Creates an instance.
          */
         public Implementation() {
@@ -93,11 +112,12 @@ public class DslCommonPlugin extends EMFPlugin {
             super.start(context);
             initExtensionRegistries();
             new DynamicPackageRegistryReader().readRegistry();
+            packageMetaDataRegistryReader = new EPackageMetaDataRegistryReader(Platform.getExtensionRegistry(), DslCommonPlugin.INSTANCE.metaDataRegistry);
+            packageMetaDataRegistryReader.start();
         }
 
         /**
-         * Initializes the extension registries and their listeners for this
-         * plugin.
+         * Initializes the extension registries and their listeners for this plugin.
          */
         private void initExtensionRegistries() {
             IExtensionRegistry registry = Platform.getExtensionRegistry();
@@ -111,13 +131,14 @@ public class DslCommonPlugin extends EMFPlugin {
 
         @Override
         public void stop(final BundleContext context) throws Exception {
+            packageMetaDataRegistryReader.stop();
+            packageMetaDataRegistryReader = null;
             super.stop(context);
             clearExtensionRegistries();
         }
 
         /**
-         * Clears the extension registries for this plugin and remove their
-         * corresponding listeners.
+         * Clears the extension registries for this plugin and remove their corresponding listeners.
          */
         private void clearExtensionRegistries() {
             IExtensionRegistry registry = Platform.getExtensionRegistry();
diff --git a/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/api/ecore/EPackageMetaData.java b/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/api/ecore/EPackageMetaData.java
new file mode 100644
index 0000000000..a4b5c580af
--- /dev/null
+++ b/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/api/ecore/EPackageMetaData.java
@@ -0,0 +1,114 @@
+/*******************************************************************************
+ * Copyright (c) 2017 Obeo.
+ * 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:
+ *    Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.sirius.common.tools.api.ecore;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Represent extra meta-data that can be associated to an EPackage but that are not modeled in Ecore.
+ * 
+ * @author pcdavid
+ */
+public class EPackageMetaData {
+    /**
+     * The nsURI of the EPackage this applies to. We use an nsURI instead of an EPackage to avoid loading the metamodel
+     * (and the plug-in that defines it) if possible.
+     */
+    private final String nsURI;
+
+    /**
+     * The name to display to end-users, which may be different from the technical EPackage.name.
+     */
+    private String displayName;
+
+    /**
+     * User-oriented documentation for the metamodel defined by the EPackage.
+     */
+    private String documentation;
+
+    /**
+     * Names of EClasses from the EPackage that are good candidates as root model elements.
+     */
+    private List<String> suggestedRoots = new ArrayList<>();
+
+    /**
+     * Create a new EPackageExtraData.
+     * 
+     * @param nsURI
+     *            the nsURI of the EPackage this applies to..
+     */
+    public EPackageMetaData(String nsURI) {
+        this.nsURI = nsURI;
+    }
+
+    /**
+     * The nsURI of the EPackage this meta-data applies to.
+     * 
+     * @return the nsURI of the EPackage.
+     */
+    public String getNsURI() {
+        return nsURI;
+    }
+
+    /**
+     * Returns the name to display to end-users, which may be different from the technical EPackage.name.
+     * 
+     * @return the name to display to end-users.
+     */
+    public String getDisplayName() {
+        return displayName;
+    }
+
+    /**
+     * Set the name to display to end-users, which may be different from the technical EPackage.name.
+     * 
+     * @param displayName
+     *            the name to display to end-users.
+     */
+    public void setDisplayName(String displayName) {
+        this.displayName = displayName;
+    }
+
+    /**
+     * Returns the user-oriented documentation for the metamodel defined by the EPackage.
+     * 
+     * @return the user-oriented documentation for the metamodel.
+     */
+    public String getDocumentation() {
+        return documentation;
+    }
+
+    /**
+     * Set the user-oriented documentation for the metamodel defined by the EPackage.
+     * 
+     * @param documentation
+     *            the user-oriented documentation for the metamodel.
+     */
+    public void setDocumentation(String documentation) {
+        this.documentation = documentation;
+    }
+
+    /**
+     * Returns the names of EClasses from the EPackage that are good candidates as root model elements.
+     * 
+     * @return the names of good root model types.
+     */
+    public List<String> getSuggestedRoots() {
+        return suggestedRoots;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("#<EPackageMetaData %s>", nsURI); //$NON-NLS-1$
+    }
+
+}
diff --git a/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/internal/ecore/EPackageMetaDataRegistry.java b/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/internal/ecore/EPackageMetaDataRegistry.java
new file mode 100644
index 0000000000..1b2cadb858
--- /dev/null
+++ b/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/internal/ecore/EPackageMetaDataRegistry.java
@@ -0,0 +1,68 @@
+/*******************************************************************************
+ * Copyright (c) 2017 Obeo.
+ * 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:
+ *    Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.sirius.common.tools.internal.ecore;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.eclipse.sirius.common.tools.api.ecore.EPackageMetaData;
+import org.eclipse.sirius.common.tools.api.util.StringUtil;
+
+/**
+ * A plain registry of {@link EPackageMetaData}, independent on where the source data come from.
+ * 
+ * @author pcdavid
+ */
+public class EPackageMetaDataRegistry {
+
+    private final Map<String, EPackageMetaData> entries = new HashMap<>();
+
+    /**
+     * Registers a new {@link EPackageMetaData}.
+     * 
+     * @param data
+     *            the {@link EPackageMetaData}
+     */
+    public synchronized void register(EPackageMetaData data) {
+        entries.put(data.getNsURI(), data);
+    }
+
+    /**
+     * Unregisters the {@link EPackageMetaData} for a specific nsURI. Does nothing if not {@link EPackageMetaData} is
+     * registered for this URI.
+     * 
+     * @param nsURI
+     *            the nsURI of the entry to remove.
+     */
+    public synchronized void unregister(String nsURI) {
+        if (!StringUtil.isEmpty(nsURI)) {
+            entries.remove(nsURI);
+        }
+    }
+
+    /**
+     * Unregisters all known {@link EPackageMetaData}.
+     */
+    public synchronized void clear() {
+        entries.clear();
+    }
+
+    /**
+     * Returns the extra data associated to the specified nsURI, if any.
+     * 
+     * @param nsURI
+     *            the nsURI of the EPackage to look for.
+     * @return the associated extra data, may be <code>null</code>.
+     */
+    public synchronized EPackageMetaData getExtraData(String nsURI) {
+        return entries.get(nsURI);
+    }
+}
diff --git a/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/internal/ecore/EPackageMetaDataRegistryReader.java b/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/internal/ecore/EPackageMetaDataRegistryReader.java
new file mode 100644
index 0000000000..576e828d05
--- /dev/null
+++ b/plugins/org.eclipse.sirius.common/src/org/eclipse/sirius/common/tools/internal/ecore/EPackageMetaDataRegistryReader.java
@@ -0,0 +1,145 @@
+/**
+ * Copyright (c) 2017 Obeo
+ * 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:
+ *  Obeo - initial API and implementation
+ */
+package org.eclipse.sirius.common.tools.internal.ecore;
+
+import org.eclipse.core.runtime.IConfigurationElement;
+import org.eclipse.core.runtime.IExtension;
+import org.eclipse.core.runtime.IExtensionPoint;
+import org.eclipse.core.runtime.IExtensionRegistry;
+import org.eclipse.core.runtime.IRegistryEventListener;
+import org.eclipse.sirius.common.tools.api.ecore.EPackageMetaData;
+import org.eclipse.sirius.common.tools.api.util.StringUtil;
+
+/**
+ * Feeds an EPackageMetaDataRegistry from extension point configuration data.
+ * 
+ * @author <a href="mailto:axel.richard@obeo.fr">Axel Richard</a>
+ * @author pcdavid
+ */
+public class EPackageMetaDataRegistryReader {
+
+    /** Extension-point ID. */
+    private static final String EPACKAGE_META_DATA_EXTENSION_POINT = "org.eclipse.sirius.common.package_meta_data"; //$NON-NLS-1$
+
+    private static final String EPACKAGE_META_DATA_ELEMENT = "ePackageMetaData"; //$NON-NLS-1$
+
+    /** nsURI attribute. */
+    private static final String NS_URI_ATTRIBUTE = "nsURI"; //$NON-NLS-1$
+
+    /** Display name attribute. */
+    private static final String DISPLAY_NAME_ATTRIBUTE = "displayName"; //$NON-NLS-1$
+
+    /** Documentation attribute. */
+    private static final String DOCUMENTATION_ATTRIBUTE = "documentation"; //$NON-NLS-1$
+
+    /** Preferred root element attribute. */
+    private static final String SUGGESTED_ROOT_ELEMENT = "suggestedRoot"; //$NON-NLS-1$
+
+    private static final String SUGGESTED_ROOT_CLASS_NAME_ATTRIBUTE = "className"; //$NON-NLS-1$
+
+    private final IExtensionRegistry extensionRegistry;
+
+    private final EPackageMetaDataRegistry metaDataRegistry;
+
+    private IRegistryEventListener listener = new EPackageExtraDataListener();
+
+    /**
+     * Creates a new EPackageExtraDataRegistry reading from the specified registry.
+     * 
+     * @param extRegistry
+     *            the registry to read configuration from.
+     * @param mdRegistry
+     *            the registry to register package metadata into.
+     */
+    public EPackageMetaDataRegistryReader(IExtensionRegistry extRegistry, EPackageMetaDataRegistry mdRegistry) {
+        this.extensionRegistry = extRegistry;
+        this.metaDataRegistry = mdRegistry;
+    }
+
+    /**
+     * Initialize the regsitry and start listening for dynamic changes.
+     */
+    public synchronized void start() {
+        for (IConfigurationElement cfg : extensionRegistry.getConfigurationElementsFor(EPACKAGE_META_DATA_EXTENSION_POINT)) {
+            EPackageMetaData data = parse(cfg);
+            if (data != null) {
+                metaDataRegistry.register(data);
+            }
+        }
+        this.extensionRegistry.addListener(listener, EPACKAGE_META_DATA_EXTENSION_POINT);
+    }
+
+    /**
+     * Clears the registry and stop listening for dynamic changes.
+     */
+    public synchronized void stop() {
+        this.extensionRegistry.removeListener(listener);
+        metaDataRegistry.clear();
+    }
+
+    private EPackageMetaData parse(IConfigurationElement cfg) {
+        if (EPACKAGE_META_DATA_ELEMENT.equals(cfg.getName())) {
+            EPackageMetaData result = new EPackageMetaData(cfg.getAttribute(NS_URI_ATTRIBUTE));
+            result.setDisplayName(cfg.getAttribute(DISPLAY_NAME_ATTRIBUTE));
+            result.setDocumentation(cfg.getAttribute(DOCUMENTATION_ATTRIBUTE));
+            for (IConfigurationElement child : cfg.getChildren(SUGGESTED_ROOT_ELEMENT)) {
+                String className = child.getAttribute(SUGGESTED_ROOT_CLASS_NAME_ATTRIBUTE);
+                if (!StringUtil.isEmpty(className)) {
+                    result.getSuggestedRoots().add(className.trim());
+                }
+            }
+            return result;
+        } else {
+            return null;
+        }
+    }
+
+    private final class EPackageExtraDataListener implements IRegistryEventListener {
+        @Override
+        public void added(IExtension[] extensions) {
+            synchronized (EPackageMetaDataRegistryReader.this) {
+                for (IExtension ext : extensions) {
+                    for (IConfigurationElement cfg : ext.getConfigurationElements()) {
+                        EPackageMetaData data = parse(cfg);
+                        if (data != null) {
+                            metaDataRegistry.register(data);
+                        }
+                    }
+                }
+            }
+        }
+
+        @Override
+        public void removed(IExtension[] extensions) {
+            synchronized (EPackageMetaDataRegistryReader.this) {
+                for (IExtension ext : extensions) {
+                    for (IConfigurationElement cfg : ext.getConfigurationElements()) {
+                        if (EPACKAGE_META_DATA_ELEMENT.equals(cfg.getName())) {
+                            String nsURI = cfg.getAttribute(NS_URI_ATTRIBUTE);
+                            metaDataRegistry.unregister(nsURI);
+                        }
+                    }
+                }
+            }
+        }
+
+        @Override
+        public void removed(IExtensionPoint[] extensionPoints) {
+            // no need to listen to this event
+        }
+
+        @Override
+        public void added(IExtensionPoint[] extensionPoints) {
+            // no need to listen to this event
+        }
+    }
+
+}
diff --git a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html
index 8178cc4d02..3bb32dbbe9 100644
--- a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html
+++ b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html
@@ -257,6 +257,10 @@
 			<li><span class="label label-success">Added</span> 
 				<code>org.eclipse.sirius.common.tools.api.util.SiriusCrossReferenceAdapterImpl.isIncluded(EReference)</code> has been overridden to consider features in the white list.
 			</li>
+			<li><span class="label label-success">Added</span> A new extension point, 
+				<code>org.eclipse.sirius.common.package_meta_data</code> has been added. It can be used to associate user-oriented meta-data to Ecore metamodels, identified by their 
+				<code>nsURI</code>: a user-oriented name/label (as opposed to the technical nsURI), a (short) description/documentation, and a list of suggested EClasses defined in the EPackage that are good candidates as root model elements.
+			</li>
 		</ul>
 		<h4 id="Changesinorg.eclipse.sirius.common.ui">Changes in 
 			<code>org.eclipse.sirius.common.ui</code> 
diff --git a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile
index 05e461b8f0..db2e5793b1 100644
--- a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile
+++ b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile
@@ -58,6 +58,7 @@ h4. Changes in @org.eclipse.sirius.common@
 
 * <span class="label label-success">Added</span> @org.eclipse.sirius.common.tools.api.util.SiriusCrossReferenceAdapterImpl.setFeatureToBeCrossReferencedWhiteList(Collection<EReference>)@ to set a white list of references that must be referenced even if the reference is derived.
 * <span class="label label-success">Added</span> @org.eclipse.sirius.common.tools.api.util.SiriusCrossReferenceAdapterImpl.isIncluded(EReference)@ has been overridden to consider features in the white list.
+* <span class="label label-success">Added</span> A new extension point, @org.eclipse.sirius.common.package_meta_data@ has been added. It can be used to associate user-oriented meta-data to Ecore metamodels, identified by their @nsURI@: a user-oriented name/label (as opposed to the technical nsURI), a (short) description/documentation, and a list of suggested EClasses defined in the EPackage that are good candidates as root model elements.
 
 h4. Changes in @org.eclipse.sirius.common.ui@