[479019] Introduce and use a MetamodelDescriptorProvider2 API

This API extends the original MetamodelDescriptorProvider API so that 
it can be called even when no Viewpoint is enabled. This allow
implementers to declare accessible metamodels in a systematic way and is
used by Sirius itself so that the Ecore models capturing representation
data are known by the interpreters even if no Viewpoint has been
selected.

Bug: 479019
Change-Id: I6243f43470522c3e1f6496bde4ac63c9a890e0ff
Signed-off-by: Cedric Brun <cedric.brun@obeo.fr>

12 files changed, 142 insertions, 36 deletions

diff --git a/plugins/org.eclipse.sirius.diagram.sequence/src/org/eclipse/sirius/diagram/sequence/business/internal/metamodel/SequenceDiagramMetamodelsProvider.java b/plugins/org.eclipse.sirius.diagram.sequence/src/org/eclipse/sirius/diagram/sequence/business/internal/metamodel/SequenceDiagramMetamodelsProvider.java
index fb54ebd849..81ea9b94ac 100644
--- a/plugins/org.eclipse.sirius.diagram.sequence/src/org/eclipse/sirius/diagram/sequence/business/internal/metamodel/SequenceDiagramMetamodelsProvider.java
+++ b/plugins/org.eclipse.sirius.diagram.sequence/src/org/eclipse/sirius/diagram/sequence/business/internal/metamodel/SequenceDiagramMetamodelsProvider.java
@@ -12,9 +12,10 @@
 package org.eclipse.sirius.diagram.sequence.business.internal.metamodel;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Set;
 
-import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider;
+import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider2;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.EcoreMetamodelDescriptor;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.MetamodelDescriptor;
 import org.eclipse.sirius.viewpoint.description.Viewpoint;
@@ -27,10 +28,10 @@ import com.google.common.collect.Sets;
  * @author <a href="mailto:cedric.brun@obeo.fr">Cedric Brun</a>
  *
  */
-public class SequenceDiagramMetamodelsProvider implements MetamodelDescriptorProvider {
+public class SequenceDiagramMetamodelsProvider implements MetamodelDescriptorProvider2 {
 
     @Override
-    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+    public Collection<MetamodelDescriptor> provides(Collection<Viewpoint> vp) {
         Set<MetamodelDescriptor> result = Sets.newLinkedHashSet();
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.diagram.sequence.SequencePackage.eINSTANCE));
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.diagram.sequence.description.DescriptionPackage.eINSTANCE));
@@ -39,5 +40,10 @@ public class SequenceDiagramMetamodelsProvider implements MetamodelDescriptorPro
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.diagram.sequence.template.TemplatePackage.eINSTANCE));
         return result;
     }
+    
+    @Override
+    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+        return Collections.<MetamodelDescriptor>emptyList();
+    }
 
 }
diff --git a/plugins/org.eclipse.sirius.diagram/src-core/org/eclipse/sirius/diagram/business/internal/dialect/DiagramMetamodelsProvider.java b/plugins/org.eclipse.sirius.diagram/src-core/org/eclipse/sirius/diagram/business/internal/dialect/DiagramMetamodelsProvider.java
index cb4d2eb094..79321ed66a 100644
--- a/plugins/org.eclipse.sirius.diagram/src-core/org/eclipse/sirius/diagram/business/internal/dialect/DiagramMetamodelsProvider.java
+++ b/plugins/org.eclipse.sirius.diagram/src-core/org/eclipse/sirius/diagram/business/internal/dialect/DiagramMetamodelsProvider.java
@@ -12,9 +12,10 @@
 package org.eclipse.sirius.diagram.business.internal.dialect;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Set;
 
-import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider;
+import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider2;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.EcoreMetamodelDescriptor;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.MetamodelDescriptor;
 import org.eclipse.sirius.viewpoint.description.Viewpoint;
@@ -27,10 +28,10 @@ import com.google.common.collect.Sets;
  * @author <a href="mailto:cedric.brun@obeo.fr">Cedric Brun</a>
  *
  */
-public class DiagramMetamodelsProvider implements MetamodelDescriptorProvider {
+public class DiagramMetamodelsProvider implements MetamodelDescriptorProvider2 {
 
     @Override
-    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+    public Collection<MetamodelDescriptor> provides(Collection<Viewpoint> vps) {
         Set<MetamodelDescriptor> result = Sets.newLinkedHashSet();
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.diagram.DiagramPackage.eINSTANCE));
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.diagram.description.DescriptionPackage.eINSTANCE));
@@ -41,4 +42,9 @@ public class DiagramMetamodelsProvider implements MetamodelDescriptorProvider {
         return result;
     }
 
+    @Override
+    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+        return Collections.<MetamodelDescriptor>emptyList();
+    }
+
 }
diff --git a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html
index e8f639440c..78d302be50 100644
--- a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html
+++ b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html
@@ -387,6 +387,10 @@
 			<li><span class="label label-success">Added</span> The class 
 				<code>org.eclipse.sirius.common.tools.api.interpreter.StandardServices</code> has been added. This class owns methods used for service: interpreter.
 			</li>
+			<li><span class="label label-success">Added</span> The class 
+				<code>org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider2</code> has been added and should be prefered instead of implementing 
+				<code>MetamodelDescriptorProvider</code>.
+			</li>
 			<li><span class="label label-info">Modified</span> 
 				<code>org.eclipse.sirius.ecore.extender.business.api.permission.IPermissionAuthority.canDeleteInstance(EObject)</code> when called for an object will not be called for children of this object as we know it will return true because if we can delete a parent object we can delete its children. 
 			</li>
diff --git a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile
index e3c44d5169..f4b05e52dc 100644
--- a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile
+++ b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile
@@ -106,6 +106,7 @@ h4. Changes in @org.eclipse.sirius@
 
 * <span class="label label-success">Added</span> The method @addEvaluateSelectionExpressionTask@ has been added in class @org.eclipse.sirius.tools.api.command.AbstractCommandFactory@ to allow selection after tool execution.
 * <span class="label label-success">Added</span> The class @org.eclipse.sirius.common.tools.api.interpreter.StandardServices@ has been added. This class owns methods used for service: interpreter.
+* <span class="label label-success">Added</span> The class @org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider2@ has been added and should be prefered instead of implementing @MetamodelDescriptorProvider@.
 * <span class="label label-info">Modified</span> @org.eclipse.sirius.ecore.extender.business.api.permission.IPermissionAuthority.canDeleteInstance(EObject)@ when called for an object will not be called for children of this object as we know it will return true because if we can delete a parent object we can delete its children. 
 * <span class="label label-info">Modified</span> @org.eclipse.sirius.tools.api.command.DCommand@ no more inherits of @IUndoableCommand@ because useless since undo/redo is managed by EMF Transaction.
 * <span class="label label-danger">Removed</span> @org.eclipse.sirius.business.api.helper.task.ICommandTask.undo()/redo()@ methods removed because they are useless since undo/redo is managed by EMF Transaction.
diff --git a/plugins/org.eclipse.sirius.ecore.extender/src/org/eclipse/sirius/ecore/extender/business/api/accessor/MetamodelDescriptor.java b/plugins/org.eclipse.sirius.ecore.extender/src/org/eclipse/sirius/ecore/extender/business/api/accessor/MetamodelDescriptor.java
index 10cb3de01b..272fbc55b3 100644
--- a/plugins/org.eclipse.sirius.ecore.extender/src/org/eclipse/sirius/ecore/extender/business/api/accessor/MetamodelDescriptor.java
+++ b/plugins/org.eclipse.sirius.ecore.extender/src/org/eclipse/sirius/ecore/extender/business/api/accessor/MetamodelDescriptor.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2009 THALES GLOBAL SERVICES.
+ * Copyright (c) 2007, 2015 THALES GLOBAL SERVICES 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
@@ -10,9 +10,11 @@
  *******************************************************************************/
 package org.eclipse.sirius.ecore.extender.business.api.accessor;
 
-//TODOCBR comment this !
 /**
- * .
+ * A Marker interface for descriptors representing metamodels. These instances
+ * will be passed around by Sirius from the MetamodelDescriptorProviders to the
+ * interpreters and model accessors which have to query for a more specific type
+ * they can handle.
  * 
  * @author cbrun
  */
diff --git a/plugins/org.eclipse.sirius.table/src/org/eclipse/sirius/table/business/internal/dialect/TableMetamodelsProvider.java b/plugins/org.eclipse.sirius.table/src/org/eclipse/sirius/table/business/internal/dialect/TableMetamodelsProvider.java
index 6c7a33e5d9..2299648808 100644
--- a/plugins/org.eclipse.sirius.table/src/org/eclipse/sirius/table/business/internal/dialect/TableMetamodelsProvider.java
+++ b/plugins/org.eclipse.sirius.table/src/org/eclipse/sirius/table/business/internal/dialect/TableMetamodelsProvider.java
@@ -12,9 +12,10 @@
 package org.eclipse.sirius.table.business.internal.dialect;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Set;
 
-import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider;
+import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider2;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.EcoreMetamodelDescriptor;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.MetamodelDescriptor;
 import org.eclipse.sirius.viewpoint.description.Viewpoint;
@@ -27,14 +28,19 @@ import com.google.common.collect.Sets;
  * @author <a href="mailto:cedric.brun@obeo.fr">Cedric Brun</a>
  *
  */
-public class TableMetamodelsProvider implements MetamodelDescriptorProvider {
+public class TableMetamodelsProvider implements MetamodelDescriptorProvider2 {
 
     @Override
-    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+    public Collection<MetamodelDescriptor> provides(Collection<Viewpoint> vp) {
         Set<MetamodelDescriptor> result = Sets.newLinkedHashSet();
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.table.metamodel.table.TablePackage.eINSTANCE));
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.table.metamodel.table.description.DescriptionPackage.eINSTANCE));
         return result;
     }
+    
+    @Override
+    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+        return Collections.<MetamodelDescriptor>emptyList();
+    }
 
 }
diff --git a/plugins/org.eclipse.sirius.tree/src/org/eclipse/sirius/tree/business/internal/dialect/TreeMetamodelsProvider.java b/plugins/org.eclipse.sirius.tree/src/org/eclipse/sirius/tree/business/internal/dialect/TreeMetamodelsProvider.java
index 1a77432fd8..d72fe1e723 100644
--- a/plugins/org.eclipse.sirius.tree/src/org/eclipse/sirius/tree/business/internal/dialect/TreeMetamodelsProvider.java
+++ b/plugins/org.eclipse.sirius.tree/src/org/eclipse/sirius/tree/business/internal/dialect/TreeMetamodelsProvider.java
@@ -12,9 +12,10 @@
 package org.eclipse.sirius.tree.business.internal.dialect;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Set;
 
-import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider;
+import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider2;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.EcoreMetamodelDescriptor;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.MetamodelDescriptor;
 import org.eclipse.sirius.viewpoint.description.Viewpoint;
@@ -27,14 +28,18 @@ import com.google.common.collect.Sets;
  * @author <a href="mailto:cedric.brun@obeo.fr">Cedric Brun</a>
  *
  */
-public class TreeMetamodelsProvider implements MetamodelDescriptorProvider {
+public class TreeMetamodelsProvider implements MetamodelDescriptorProvider2 {
 
     @Override
-    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+    public Collection<MetamodelDescriptor> provides(Collection<Viewpoint> vp) {
         Set<MetamodelDescriptor> result = Sets.newLinkedHashSet();
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.tree.TreePackage.eINSTANCE));
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.tree.description.DescriptionPackage.eINSTANCE));
         return result;
     }
 
+    @Override
+    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+        return Collections.<MetamodelDescriptor> emptyList();
+    }
 }
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/extender/MetamodelDescriptorProvider.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/extender/MetamodelDescriptorProvider.java
index f6af82e2ee..220ec0959e 100644
--- a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/extender/MetamodelDescriptorProvider.java
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/extender/MetamodelDescriptorProvider.java
@@ -18,16 +18,24 @@ import org.eclipse.sirius.viewpoint.description.Viewpoint;
 /**
  * Provider able to return a list of MetamodelDescriptor from viewpoints.
  * 
+ * This interfaces is deprecated, MetamodelDescriptorProvider2 should be used
+ * instead as it provides the ability to handle several Viewpoints at once.
+ * 
  * @author cbrun
  * 
  */
+@Deprecated
 public interface MetamodelDescriptorProvider {
     /**
      * return the list of metamodel descritor provided by the viewpoint.
      * 
+     * This method is deprecated and will not be called if the class implements
+     * {@link MetamodelDescriptorProvider2}.
+     * 
      * @param vp
      *            any representation description.
      * @return the list of metamodel descritor provided by the viewpoint.
      */
+    @Deprecated
     Collection<MetamodelDescriptor> provides(Viewpoint vp);
 }
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/extender/MetamodelDescriptorProvider2.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/extender/MetamodelDescriptorProvider2.java
new file mode 100644
index 0000000000..b8ab794921
--- /dev/null
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/extender/MetamodelDescriptorProvider2.java
@@ -0,0 +1,39 @@
+/*******************************************************************************
+ * Copyright (c) 2015 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.business.api.extender;
+
+import java.util.Collection;
+
+import org.eclipse.sirius.ecore.extender.business.api.accessor.MetamodelDescriptor;
+import org.eclipse.sirius.viewpoint.description.Viewpoint;
+
+/**
+ * Provider able to return a list of MetamodelDescriptor from viewpoints. This
+ * is an evolution of the {@link MetamodelDescriptorProvider} API so that
+ * implementers can declare MetamodelDescriptors even if no Viewpoint is
+ * enabled.
+ * 
+ * @author cbrun
+ * 
+ */
+public interface MetamodelDescriptorProvider2 extends MetamodelDescriptorProvider {
+    /**
+     * Return the list of metamodel descritor provided by the selected
+     * viewpoints.
+     * 
+     * @param vps
+     *            A list of selected Viewpoints. This list might be empty and
+     *            yet the adopter might want to provide metamodel descriptors
+     *            anyway.
+     * @return the list of metamodel descritor provided by the viewpoint.
+     */
+    Collection<MetamodelDescriptor> provides(Collection<Viewpoint> vps);
+}
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/dialect/ViewpointMetamodelsProvider.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/dialect/ViewpointMetamodelsProvider.java
index 2aa601c4fa..99729d845a 100644
--- a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/dialect/ViewpointMetamodelsProvider.java
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/dialect/ViewpointMetamodelsProvider.java
@@ -12,9 +12,10 @@
 package org.eclipse.sirius.business.internal.dialect;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Set;
 
-import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider;
+import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider2;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.EcoreMetamodelDescriptor;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.MetamodelDescriptor;
 import org.eclipse.sirius.viewpoint.description.Viewpoint;
@@ -27,10 +28,10 @@ import com.google.common.collect.Sets;
  * @author <a href="mailto:cedric.brun@obeo.fr">Cedric Brun</a>
  *
  */
-public class ViewpointMetamodelsProvider implements MetamodelDescriptorProvider {
+public class ViewpointMetamodelsProvider implements MetamodelDescriptorProvider2 {
 
     @Override
-    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+    public Collection<MetamodelDescriptor> provides(Collection<Viewpoint> vp) {
         Set<MetamodelDescriptor> result = Sets.newLinkedHashSet();
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.viewpoint.ViewpointPackage.eINSTANCE));
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.viewpoint.description.DescriptionPackage.eINSTANCE));
@@ -41,5 +42,10 @@ public class ViewpointMetamodelsProvider implements MetamodelDescriptorProvider
         result.add(new EcoreMetamodelDescriptor(org.eclipse.sirius.description.contribution.ContributionPackage.eINSTANCE));
         return result;
     }
+    
+    @Override
+    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+        return Collections.<MetamodelDescriptor>emptyList();
+    }
 
 }
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/extender/EcoreIntrinsicMetamodelDescriptorProvider.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/extender/EcoreIntrinsicMetamodelDescriptorProvider.java
index 3031604b03..ccb4ccfe7f 100644
--- a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/extender/EcoreIntrinsicMetamodelDescriptorProvider.java
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/extender/EcoreIntrinsicMetamodelDescriptorProvider.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008, 2010 THALES GLOBAL SERVICES.
+ * Copyright (c) 2008, 2015 THALES GLOBAL SERVICES 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
@@ -12,9 +12,10 @@ package org.eclipse.sirius.business.internal.extender;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 
 import org.eclipse.emf.ecore.EPackage;
-import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider;
+import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider2;
 import org.eclipse.sirius.business.api.query.ViewpointQuery;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.EcoreMetamodelDescriptor;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.MetamodelDescriptor;
@@ -28,23 +29,25 @@ import org.eclipse.sirius.viewpoint.description.Viewpoint;
  * @author cbrun
  * 
  */
-public class EcoreIntrinsicMetamodelDescriptorProvider implements MetamodelDescriptorProvider {
+public class EcoreIntrinsicMetamodelDescriptorProvider implements MetamodelDescriptorProvider2 {
     /**
      * 
      * {@inheritDoc}
      */
-    public Collection<MetamodelDescriptor> provides(final Viewpoint vp) {
+    public Collection<MetamodelDescriptor> provides(final Collection<Viewpoint> vps) {
         final Collection<MetamodelDescriptor> result = new ArrayList<MetamodelDescriptor>();
 
-        for (final RepresentationDescription desc : new ViewpointQuery(vp).getAllRepresentationDescriptions()) {
-            for (final EPackage pak : desc.getMetamodel()) {
-                result.add(getMetamodelDescriptor(pak));
+        for (Viewpoint vp : vps) {
+            for (final RepresentationDescription desc : new ViewpointQuery(vp).getAllRepresentationDescriptions()) {
+                for (final EPackage pak : desc.getMetamodel()) {
+                    result.add(getMetamodelDescriptor(pak));
+                }
             }
-        }
-
-        for (final RepresentationExtensionDescription ext : vp.getOwnedRepresentationExtensions()) {
-            for (final EPackage pak : ext.getMetamodel()) {
-                result.add(getMetamodelDescriptor(pak));
+            
+            for (final RepresentationExtensionDescription ext : vp.getOwnedRepresentationExtensions()) {
+                for (final EPackage pak : ext.getMetamodel()) {
+                    result.add(getMetamodelDescriptor(pak));
+                }
             }
         }
 
@@ -60,5 +63,10 @@ public class EcoreIntrinsicMetamodelDescriptorProvider implements MetamodelDescr
             return new EcoreMetamodelDescriptor(pak);
         }
     }
+    
+    @Override
+    public Collection<MetamodelDescriptor> provides(Viewpoint vp) {
+        return Collections.<MetamodelDescriptor>emptyList();
+    }
 
 }
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/extender/MetamodelDescriptorManagerImpl.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/extender/MetamodelDescriptorManagerImpl.java
index 12d9837d33..2b2e99b6ad 100644
--- a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/extender/MetamodelDescriptorManagerImpl.java
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/extender/MetamodelDescriptorManagerImpl.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008 THALES GLOBAL SERVICES.
+ * Copyright (c) 2008, 2015 THALES GLOBAL SERVICES 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
@@ -12,16 +12,19 @@ package org.eclipse.sirius.business.internal.extender;
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.HashSet;
 import java.util.List;
 
 import org.eclipse.sirius.business.api.extender.MetamodelDescriptorManager;
 import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider;
+import org.eclipse.sirius.business.api.extender.MetamodelDescriptorProvider2;
 import org.eclipse.sirius.common.tools.api.util.EclipseUtil;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.MetamodelDescriptor;
 import org.eclipse.sirius.viewpoint.SiriusPlugin;
 import org.eclipse.sirius.viewpoint.description.Viewpoint;
 
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Sets;
+
 /**
  * Implementation for the manager.
  * 
@@ -58,12 +61,24 @@ public class MetamodelDescriptorManagerImpl implements MetamodelDescriptorManage
      * {@inheritDoc}
      */
     public Collection<MetamodelDescriptor> provides(final Collection<Viewpoint> enabledViewpoints) {
-        final Collection<MetamodelDescriptor> result = new HashSet<MetamodelDescriptor>();
+        final Collection<MetamodelDescriptor> result = Sets.newLinkedHashSet();
+        for (MetamodelDescriptorProvider2 provider : Iterables.filter(providers, MetamodelDescriptorProvider2.class)) {
+            final Collection<MetamodelDescriptor> provided = provider.provides(enabledViewpoints);
+            if (provided != null) {
+                result.addAll(provided);
+            }
+        }
         for (Viewpoint vp : enabledViewpoints) {
             for (MetamodelDescriptorProvider provider : providers) {
-                final Collection<MetamodelDescriptor> provided = provider.provides(vp);
-                if (provided != null) {
-                    result.addAll(provided);
+                /*
+                 * Implementers of MetamodelDescriptorProvider2 have been called
+                 * before.
+                 */
+                if (!(provider instanceof MetamodelDescriptorProvider2)) {
+                    final Collection<MetamodelDescriptor> provided = provider.provides(vp);
+                    if (provided != null) {
+                        result.addAll(provided);
+                    }
                 }
             }
         }