[516669] Allow delegating representation resource strategy

* use the dRepresentationLocationRule extension point to delegate the
management of the resource URI that is used to store the representation.
As a default extension is provided by Sirius, a priority attribute has
been added on the extension point so that clients may provide their own
extension.
* createRepresentationInSeparateResource system property is renamed to
createLocalRepresentationInSeparateResource and is used only
for resources of type platform.

Bug: 516669
Change-Id: Icbd5f68f90d7f9299cce6ac7e19d3343bf221d53
Signed-off-by: Laurent Fasani <laurent.fasani@obeo.fr>

12 files changed, 519 insertions, 145 deletions

diff --git a/plugins/org.eclipse.sirius/plugin.xml b/plugins/org.eclipse.sirius/plugin.xml
index 747ecd19af..97af602fe1 100644
--- a/plugins/org.eclipse.sirius/plugin.xml
+++ b/plugins/org.eclipse.sirius/plugin.xml
@@ -454,5 +454,12 @@
             class="org.eclipse.sirius.business.internal.dialect.ViewpointMetamodelsProvider">
       </descriptorprovider>
    </extension>
+   <extension
+         point="org.eclipse.sirius.dRepresentationLocationRule">
+      <rule
+            class="org.eclipse.sirius.business.internal.representation.DRepLocationRuleForLocalResource"
+            priority="core">
+      </rule>
+   </extension>
 
 </plugin>
diff --git a/plugins/org.eclipse.sirius/schema/dRepresentationLocationRule.exsd b/plugins/org.eclipse.sirius/schema/dRepresentationLocationRule.exsd
index f1193a22ba..781bfc5cbf 100644
--- a/plugins/org.eclipse.sirius/schema/dRepresentationLocationRule.exsd
+++ b/plugins/org.eclipse.sirius/schema/dRepresentationLocationRule.exsd
@@ -59,6 +59,25 @@
                </appinfo>
             </annotation>
          </attribute>
+         <attribute name="priority" use="default" value="normal">
+            <annotation>
+               <documentation>
+                  the provider priority. 
+ * core is the lowest priority and is reserved for Sirius and Sirius based applications. Clients should not use that priority.
+ * normal and high are intented to be used by clients.
+               </documentation>
+            </annotation>
+            <simpleType>
+               <restriction base="string">
+                  <enumeration value="core">
+                  </enumeration>
+                  <enumeration value="normal">
+                  </enumeration>
+                  <enumeration value="high">
+                  </enumeration>
+               </restriction>
+            </simpleType>
+         </attribute>
       </complexType>
    </element>
 
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/helper/SiriusUtil.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/helper/SiriusUtil.java
index d86baeb079..370b03f4c4 100644
--- a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/helper/SiriusUtil.java
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/helper/SiriusUtil.java
@@ -53,6 +53,9 @@ public final class SiriusUtil {
     /** The file extension for representation files. */
     public static final String REPRESENTATION_FILE_EXTENSION = "srm"; //$NON-NLS-1$
 
+    /** The name of the folder containing srm files. */
+    public static final String REPRESENTATIONS_FOLDER_NAME = ".representations"; //$NON-NLS-1$
+
     /** The "environment:/" uri scheme. */
     public static final String ENVIRONMENT_URI_SCHEME = "environment"; //$NON-NLS-1$
 
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/query/FileQuery.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/query/FileQuery.java
index 61c5a092d5..6896140371 100644
--- a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/query/FileQuery.java
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/query/FileQuery.java
@@ -10,13 +10,10 @@
  *******************************************************************************/
 package org.eclipse.sirius.business.api.query;
 
-import java.util.List;
-
 import org.eclipse.core.resources.IFile;
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.sirius.business.api.helper.SiriusUtil;
-import org.eclipse.sirius.business.api.session.danalysis.DRepresentationLocationRule;
-import org.eclipse.sirius.common.tools.api.util.EclipseUtil;
+import org.eclipse.sirius.business.internal.representation.DRepresentationLocationRuleRegistry;
 
 /**
  * Query allowing to determine the type of a file (i.e. if it contains a VSM, a DAnalysis...). It is leaner than the
@@ -87,10 +84,7 @@ public class FileQuery {
      * @return true if the file is dedicated to representations, false otherwise
      */
     public boolean isSrmFile() {
-        List<DRepresentationLocationRule> extensionPointRules = EclipseUtil.getExtensionPlugins(DRepresentationLocationRule.class, DRepresentationLocationRule.ID,
-                DRepresentationLocationRule.CLASS_ATTRIBUTE);
-
-        boolean isSrmFile = extensionPointRules.stream().filter(rule -> rule.isARepresentationResource(fileExtension)).findFirst().isPresent();
+        boolean isSrmFile = DRepresentationLocationRuleRegistry.getInstance().getRepLocationRules().stream().filter(rule -> rule.isARepresentationFileExtension(fileExtension)).findFirst().isPresent();
         if (!isSrmFile) {
             if (repResourceFactory == null) {
                 repResourceFactory = Resource.Factory.Registry.INSTANCE.getExtensionToFactoryMap().get(SiriusUtil.REPRESENTATION_FILE_EXTENSION);
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/session/danalysis/DRepresentationLocationRule.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/session/danalysis/DRepresentationLocationRule.java
index 7cd4904cb0..5646320e9c 100644
--- a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/session/danalysis/DRepresentationLocationRule.java
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/api/session/danalysis/DRepresentationLocationRule.java
@@ -24,16 +24,6 @@ import org.eclipse.sirius.viewpoint.DRepresentation;
 public interface DRepresentationLocationRule {
 
     /**
-     * The extension point id.
-     */
-    String ID = "org.eclipse.sirius.dRepresentationLocationRule"; //$NON-NLS-1$
-
-    /**
-     * The class attribute.
-     */
-    String CLASS_ATTRIBUTE = "class"; //$NON-NLS-1$
-
-    /**
      * Indicates if this {@link DRepresentationLocationRule} provides a custom URI. If not and if there is no other
      * {@link DRepresentationLocationRule} that provides, Sirius fall back to the default implementation.
      * 
@@ -43,7 +33,7 @@ public interface DRepresentationLocationRule {
      *            the DView resource
      * @return the value
      */
-    boolean provides(DRepresentation representation, Resource dViewResource);
+    boolean providesURI(DRepresentation representation, Resource dViewResource);
 
     /**
      * Provides the new URI for the given representation.
@@ -64,5 +54,5 @@ public interface DRepresentationLocationRule {
      * 
      * @return true if the fileExtension is known as a representation file
      */
-    Boolean isARepresentationResource(String fileExtension);
+    Boolean isARepresentationFileExtension(String fileExtension);
 }
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepLocationRuleForLocalResource.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepLocationRuleForLocalResource.java
new file mode 100644
index 0000000000..8ca5654c15
--- /dev/null
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepLocationRuleForLocalResource.java
@@ -0,0 +1,140 @@
+/*******************************************************************************
+ * Copyright (c) 2017 THALES GLOBAL SERVICES
+ * 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.internal.representation;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.eclipse.emf.common.util.TreeIterator;
+import org.eclipse.emf.common.util.URI;
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.emf.ecore.resource.Resource;
+import org.eclipse.emf.ecore.resource.ResourceSet;
+import org.eclipse.sirius.business.api.helper.SiriusUtil;
+import org.eclipse.sirius.business.api.query.URIQuery;
+import org.eclipse.sirius.business.api.session.danalysis.DRepresentationLocationRule;
+import org.eclipse.sirius.viewpoint.DRepresentation;
+
+/**
+ * This implementation to {@link DRepresentationLocationRule} give a behavior for representation resources in local
+ * workspace.
+ * 
+ * @author <a href="mailto:laurent.fasani@obeo.fr">Laurent Fasani</a>
+ */
+public class DRepLocationRuleForLocalResource implements DRepresentationLocationRule {
+
+    @Override
+    public boolean providesURI(DRepresentation representation, Resource dViewResource) {
+        return !new URIQuery(dViewResource.getURI()).isCDOURI();
+    }
+
+    @Override
+    public URI getResourceURI(DRepresentation representation, Resource airdResource) {
+        URI repResourceURI = null;
+        if (Boolean.getBoolean("createLocalRepresentationInSeparateResource")) { //$NON-NLS-1$
+            repResourceURI = getDedicatedRepResourceURI(representation, airdResource);
+        } else {
+            repResourceURI = airdResource.getURI();
+        }
+        return repResourceURI;
+    }
+
+    /**
+     * Create the representation resource URI so that the representation can be stored in a specific resource.<br/>
+     * The URI is based on the aird resource URI. Only the last part of the segment is changed.
+     * 
+     * @param airdResource
+     *            the aird resource
+     * @param representation
+     *            the representation
+     * @return the representation URI
+     */
+    protected URI getDedicatedRepResourceURI(DRepresentation representation, Resource airdResource) {
+        int count = 0;
+        ResourceSet resourceSet = airdResource.getResourceSet();
+        URI repUri = createRepURI(airdResource, representation, count++);
+        while (!isUsableURI(repUri, resourceSet, representation)) {
+            repUri = createRepURI(airdResource, representation, count++);
+        }
+        return repUri;
+    }
+
+    private boolean isUsableURI(URI repUri, ResourceSet resourceSet, DRepresentation representation) {
+        boolean usableURI = true;
+        Resource resource = resourceSet.getResource(repUri, false);
+        // A usable URI is when the resource is not already in the resourceSet or does not exist, that is, is not
+        // loadable
+        usableURI = resource == null && !existsResource(repUri, resourceSet);
+
+        // We consider the URI usable if the representation is already in the resource
+        if (resource != null) {
+            TreeIterator<EObject> allContents = resource.getAllContents();
+            while (allContents.hasNext()) {
+                EObject object = allContents.next();
+                if (object instanceof DRepresentation) {
+                    if (representation.equals(object)) {
+                        usableURI = true;
+                        break;
+                    } else {
+                        allContents.prune();
+                    }
+                }
+            }
+        }
+        return usableURI;
+    }
+
+    /**
+     * Indicates if the given uri corresponds to a resource that then could be loaded and added to the resourceSet.
+     * 
+     * @param repUri
+     *            the resource URI
+     * @param resourceSet
+     *            the resourceSet
+     * @return true if the resource exists.
+     */
+    protected boolean existsResource(URI repUri, ResourceSet resourceSet) {
+        return resourceSet.getURIConverter().exists(repUri, null);
+    }
+
+    /**
+     * Create the representation URI based on the aird resource URI. Only the last part of the segment is changed.
+     * 
+     * @param airdResource
+     *            the aird resource
+     * @param representation
+     *            the representation
+     * @param count
+     * @return the representation URI
+     */
+    private URI createRepURI(Resource airdResource, DRepresentation representation, int count) {
+        // get the representation URI fragment
+        String repName = representation.getName().replace(' ', '_');
+        if (count > 0) {
+            repName += String.valueOf(count);
+        }
+        URI airdURI = airdResource.getURI();
+
+        List<String> srmFileSegments = new ArrayList<>(airdURI.segmentsList());
+        srmFileSegments.remove(srmFileSegments.size() - 1);
+        srmFileSegments.add(SiriusUtil.REPRESENTATIONS_FOLDER_NAME);
+        srmFileSegments.add(repName + "." + SiriusUtil.REPRESENTATION_FILE_EXTENSION); //$NON-NLS-1$
+
+        // return the URI
+        return URI.createHierarchicalURI(airdURI.scheme(), airdURI.authority(), airdURI.device(), srmFileSegments.toArray(new String[srmFileSegments.size()]), airdURI.query(), airdURI.fragment());
+    }
+
+    @Override
+    public Boolean isARepresentationFileExtension(String fileExtension) {
+        return SiriusUtil.REPRESENTATION_FILE_EXTENSION.equals(fileExtension);
+    }
+
+}
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepresentationLocationManager.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepresentationLocationManager.java
new file mode 100644
index 0000000000..f89cfbe503
--- /dev/null
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepresentationLocationManager.java
@@ -0,0 +1,65 @@
+/*******************************************************************************
+ * Copyright (c) 2017 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
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.sirius.business.internal.representation;
+
+import java.util.Optional;
+
+import org.eclipse.emf.common.util.URI;
+import org.eclipse.emf.ecore.resource.Resource;
+import org.eclipse.emf.ecore.resource.ResourceSet;
+import org.eclipse.sirius.business.api.session.danalysis.DRepresentationLocationRule;
+import org.eclipse.sirius.viewpoint.DRepresentation;
+
+/**
+ * This manager is responsible to retrieve or create the {@link Resource} of a {@link DRepresentation}.
+ * 
+ * @author fbarbin
+ *
+ */
+public class DRepresentationLocationManager {
+
+    /**
+     * Get or creates (if it does not exist) the corresponding {@link Resource} for the given representation.
+     * 
+     * @param representation
+     *            the current representation.
+     * @param airdResource
+     *            the aird resource from which the representation will be referenced.
+     * @return the representation resource.
+     */
+    public Resource getOrCreateRepresentationResource(DRepresentation representation, Resource airdResource) {
+        Resource resource = null;
+        ResourceSet resourceSet = airdResource != null ? airdResource.getResourceSet() : null;
+        if (resourceSet != null) {
+            // Get the fragment of the URI
+            resource = getURIFromExtensionPoint(representation, airdResource).map(repResourceURI -> {
+                // get or create resource
+                Resource res = resourceSet.getResource(repResourceURI, false);
+                if (res == null) {
+                    if (resourceSet.getURIConverter().exists(repResourceURI, null)) {
+                        // load the resource in case the representation have to be added in a non loaded resource
+                        res = resourceSet.getResource(repResourceURI, true);
+                    } else {
+                        res = resourceSet.createResource(repResourceURI);
+                    }
+                }
+                return res;
+            }).orElse(null);
+        }
+        return resource;
+    }
+
+    private Optional<URI> getURIFromExtensionPoint(DRepresentation representation, Resource airdResource) {
+        Optional<DRepresentationLocationRule> representationLocationRule = DRepresentationLocationRuleRegistry.getInstance().getRepresentationLocationRule(representation, airdResource);
+
+        return representationLocationRule.map(r -> r.getResourceURI(representation, airdResource));
+    }
+}
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepresentationLocationRuleRegistry.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepresentationLocationRuleRegistry.java
new file mode 100644
index 0000000000..92ee05f833
--- /dev/null
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepresentationLocationRuleRegistry.java
@@ -0,0 +1,125 @@
+/*******************************************************************************
+ * Copyright (c) 2017 THALES GLOBAL SERVICES.
+ * 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.internal.representation;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+
+import org.eclipse.emf.ecore.resource.Resource;
+import org.eclipse.sirius.business.api.resource.strategy.ResourceStrategy;
+import org.eclipse.sirius.business.api.session.danalysis.DRepresentationLocationRule;
+import org.eclipse.sirius.viewpoint.DRepresentation;
+
+/**
+ * Manage the available {@link ResourceStrategy}.
+ * 
+ * @author <a href="mailto:laurent.fasani@obeo.fr">Laurent Fasani</a>
+ */
+public final class DRepresentationLocationRuleRegistry {
+
+    /**
+     * The singleton instance of the ResourceStrategyRegistry.
+     */
+    private static final DRepresentationLocationRuleRegistry INSTANCE = new DRepresentationLocationRuleRegistry();
+
+    private Map<DRepresentationLocationRule, Priority> repLocationRules = new HashMap<>();
+
+    private DRepresentationLocationRuleRegistry() {
+    }
+
+    public static DRepresentationLocationRuleRegistry getInstance() {
+        return INSTANCE;
+    }
+
+    /**
+     * Priority used to choose the right extension.
+     * 
+     * @author lfasani
+     *
+     */
+    public enum Priority {
+        /**
+         * Core priority. Clients should not use that priority.
+         */
+        CORE(0),
+        /**
+         * Normal priority.
+         */
+        NORMAL(1),
+        /**
+         * High priority.
+         */
+        HIGH(2);
+
+        private int priority;
+
+        Priority(int priority) {
+            this.priority = priority;
+        }
+
+        public int getPriority() {
+            return priority;
+        }
+    }
+
+    /**
+     * Add a DRepresentationLocationRule to the registry.
+     * 
+     * @param repLocationRule
+     *            the DRepresentationLocationRule
+     * @param priority
+     *            the priority
+     */
+    public void addRepLocationRule(DRepresentationLocationRule repLocationRule, Priority priority) {
+        repLocationRules.put(repLocationRule, priority);
+    }
+
+    /**
+     * Remove a DRepresentationLocationRule to the registry.
+     * 
+     * @param repLocationRule
+     *            the repLocationRule
+     */
+    public void removeRepLocationRule(DRepresentationLocationRule repLocationRule) {
+        repLocationRules.remove(repLocationRule);
+    }
+
+    public Set<DRepresentationLocationRule> getRepLocationRules() {
+        return repLocationRules.keySet();
+    }
+
+    /**
+     * Removes all extensions from the registry. This will be called at plugin stopping.
+     */
+    public void dispose() {
+        repLocationRules.clear();
+    }
+
+    /**
+     * Get the compatible {@link DRepresentationLocationRule} that is one which provides and with highest priority.
+     * </br>
+     * If several are found, the first is returned.
+     * 
+     * @param representation
+     *            the current representation.
+     * @param airdResource
+     *            the aird resource from which the representation will be referenced.
+     * @return the corresponding {@link ResourceStrategy}
+     */
+    public Optional<DRepresentationLocationRule> getRepresentationLocationRule(DRepresentation representation, Resource airdResource) {
+        Optional<DRepresentationLocationRule> repLocRule = repLocationRules.keySet().stream().filter(locRule -> locRule.providesURI(representation, airdResource)).sorted((locRule1, locRule2) -> {
+            return repLocationRules.get(locRule2).getPriority() - repLocationRules.get(locRule1).getPriority();
+        }).findFirst();
+        return repLocRule;
+    }
+}
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepresentationLocationRuleRegistryListener.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepresentationLocationRuleRegistryListener.java
new file mode 100644
index 0000000000..d2c6f4e5dc
--- /dev/null
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/representation/DRepresentationLocationRuleRegistryListener.java
@@ -0,0 +1,134 @@
+/*******************************************************************************
+ * Copyright (c) 2017 THALES GLOBAL SERVICES.
+ * 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.internal.representation;
+
+import java.util.Collection;
+
+import org.eclipse.core.runtime.CoreException;
+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.core.runtime.Platform;
+import org.eclipse.core.runtime.Status;
+import org.eclipse.sirius.business.api.session.danalysis.DRepresentationLocationRule;
+import org.eclipse.sirius.business.internal.representation.DRepresentationLocationRuleRegistry.Priority;
+import org.eclipse.sirius.viewpoint.Messages;
+import org.eclipse.sirius.viewpoint.SiriusPlugin;
+
+/**
+ * This listener will allow to be aware of contribution changes against the dRepresentationLocationRule extension point.
+ * 
+ * @author <a href="mailto:laurent.fasani@obeo.fr">Laurent Fasani</a>
+ */
+public class DRepresentationLocationRuleRegistryListener implements IRegistryEventListener {
+
+    /** Name of the extension point to parse for extensions. */
+    public static final String REP_LOCATION_RULE_EXTENSION_POINT = SiriusPlugin.ID + ".dRepresentationLocationRule"; //$NON-NLS-1$
+
+    /** Name of the extension point's "dRepresentationLocationRule" tag. */
+    private static final String REP_LOCATION_RULE_TAG_EXTENSION = "dRepresentationLocationRule"; //$NON-NLS-1$
+
+    /** Name of the dRepresentationLocationRule extension point's tag "class" attribute. */
+    private static final String REP_LOCATION_RULE_CLASS_ATTRIBUTE = "class"; //$NON-NLS-1$
+
+    /** Name of the dRepresentationLocationRule extension point's tag "priority" attribute. */
+    private static final String REP_LOCATION_RULE_CLASS_PRIORITY = "priority"; //$NON-NLS-1$
+
+    /**
+     * Register this listener and parse initial contributions.
+     */
+    public void init() {
+        IExtensionRegistry registry = Platform.getExtensionRegistry();
+        registry.addListener(this, REP_LOCATION_RULE_EXTENSION_POINT);
+        parseInitialContributions();
+    }
+
+    @Override
+    public void added(IExtension[] extensions) {
+        for (IExtension extension : extensions) {
+            parseExtension(extension);
+        }
+    }
+
+    @Override
+    public void added(IExtensionPoint[] extensionPoints) {
+        // no need to listen to this event
+    }
+
+    @Override
+    public void removed(IExtension[] extensions) {
+        for (IExtension extension : extensions) {
+            final IConfigurationElement[] configElements = extension.getConfigurationElements();
+            for (IConfigurationElement elem : configElements) {
+                if (REP_LOCATION_RULE_TAG_EXTENSION.equals(elem.getName())) {
+                    final String extensionClassName = elem.getAttribute(REP_LOCATION_RULE_CLASS_ATTRIBUTE);
+                    Collection<DRepresentationLocationRule> repLocationRules = DRepresentationLocationRuleRegistry.getInstance().getRepLocationRules();
+                    for (DRepresentationLocationRule repLocationRule : repLocationRules) {
+                        if (extensionClassName.equals(repLocationRule.getClass())) {
+                            DRepresentationLocationRuleRegistry.getInstance().removeRepLocationRule(repLocationRule);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    @Override
+    public void removed(IExtensionPoint[] extensionPoints) {
+        // no need to listen to this event
+    }
+
+    /**
+     * Though this listener reacts to the extension point changes, there could have been contributions before it's been
+     * registered. This will parse these initial contributions.
+     */
+    public void parseInitialContributions() {
+        final IExtensionRegistry registry = Platform.getExtensionRegistry();
+
+        for (IExtension extension : registry.getExtensionPoint(REP_LOCATION_RULE_EXTENSION_POINT).getExtensions()) {
+            parseExtension(extension);
+        }
+    }
+
+    /**
+     * Parses a single extension contribution.
+     * 
+     * @param extension
+     *            Parses the given extension and adds its contribution to the registry.
+     */
+    private void parseExtension(IExtension extension) {
+        final IConfigurationElement[] configElements = extension.getConfigurationElements();
+        for (IConfigurationElement elem : configElements) {
+            try {
+                Object contribution = elem.createExecutableExtension(REP_LOCATION_RULE_CLASS_ATTRIBUTE); // $NON-NLS-1$
+                if (contribution instanceof DRepresentationLocationRule) {
+                    String priorityStr = elem.getAttribute(REP_LOCATION_RULE_CLASS_PRIORITY);
+                    Priority priority = DRepresentationLocationRuleRegistry.Priority.valueOf(priorityStr.toUpperCase());
+                    DRepresentationLocationRuleRegistry.getInstance().addRepLocationRule((DRepresentationLocationRule) contribution, priority);
+                }
+            } catch (CoreException | IllegalArgumentException | NullPointerException e) {
+                SiriusPlugin.getDefault().getLog().log(new Status(Status.WARNING, SiriusPlugin.ID, Messages.AbstractSiriusMigrationService_contributionInstantiationErrorMsg, e));
+            }
+        }
+    }
+
+    /**
+     * Remove this listener and flush the associated registry.
+     */
+    public void dispose() {
+        IExtensionRegistry registry = Platform.getExtensionRegistry();
+        registry.removeListener(this);
+        DRepresentationLocationRuleRegistry.getInstance().dispose();
+    }
+
+}
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/session/danalysis/DAnalysisSessionServicesImpl.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/session/danalysis/DAnalysisSessionServicesImpl.java
index e1ba3e9678..d1cab7b3b4 100644
--- a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/session/danalysis/DAnalysisSessionServicesImpl.java
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/session/danalysis/DAnalysisSessionServicesImpl.java
@@ -34,6 +34,7 @@ import org.eclipse.sirius.business.api.session.danalysis.DAnalysisSelector;
 import org.eclipse.sirius.business.api.session.danalysis.DAnalysisSessionHelper;
 import org.eclipse.sirius.business.api.session.danalysis.DAnalysisSessionService;
 import org.eclipse.sirius.business.internal.query.DRepresentationDescriptorInternalHelper;
+import org.eclipse.sirius.business.internal.representation.DRepresentationLocationManager;
 import org.eclipse.sirius.common.tools.api.util.EqualityHelper;
 import org.eclipse.sirius.viewpoint.DAnalysis;
 import org.eclipse.sirius.viewpoint.DAnalysisCustomData;
@@ -359,13 +360,7 @@ public class DAnalysisSessionServicesImpl implements SessionService, DAnalysisSe
             analysis.getOwnedViews().add(dView);
         }
 
-        Resource resourceforRepresentation = null;
-        if (Boolean.getBoolean("createRepresentationInSeparateResource")) { //$NON-NLS-1$
-            resourceforRepresentation = representationLocationManager.getOrCreateRepresentationResource(representation, dView.eResource());
-        }
-        if (resourceforRepresentation == null) {
-            resourceforRepresentation = dView.eResource();
-        }
+        Resource resourceforRepresentation = representationLocationManager.getOrCreateRepresentationResource(representation, dView.eResource());
         if (resourceforRepresentation != null) {
             session.registerResourceInCrossReferencer(resourceforRepresentation);
             resourceforRepresentation.getContents().add(representation);
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/session/danalysis/DRepresentationLocationManager.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/session/danalysis/DRepresentationLocationManager.java
deleted file mode 100644
index 8924ae1928..0000000000
--- a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/business/internal/session/danalysis/DRepresentationLocationManager.java
+++ /dev/null
@@ -1,105 +0,0 @@
-/*******************************************************************************
- * Copyright (c) 2017 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
- * http://www.eclipse.org/legal/epl-v10.html
- *
- * Contributors:
- *    Obeo - initial API and implementation
- *******************************************************************************/
-package org.eclipse.sirius.business.internal.session.danalysis;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Optional;
-
-import org.eclipse.emf.common.util.URI;
-import org.eclipse.emf.ecore.resource.Resource;
-import org.eclipse.emf.ecore.resource.ResourceSet;
-import org.eclipse.sirius.business.api.helper.SiriusUtil;
-import org.eclipse.sirius.business.api.session.danalysis.DRepresentationLocationRule;
-import org.eclipse.sirius.common.tools.api.util.EclipseUtil;
-import org.eclipse.sirius.viewpoint.DRepresentation;
-
-import com.google.common.collect.Lists;
-
-/**
- * This manager is responsible to retrieve or create the {@link Resource} of a {@link DRepresentation}.
- * 
- * @author fbarbin
- *
- */
-public class DRepresentationLocationManager {
-
-    /**
-     * Get or creates (if it does not exist) the corresponding {@link Resource} for the given representation.
-     * 
-     * @param representation
-     *            the current representation.
-     * @param aird
-     *            the aird resource from which the representation will be referenced.
-     * @return the representation resource.
-     */
-    public Resource getOrCreateRepresentationResource(DRepresentation representation, Resource aird) {
-        Resource resource = null;
-        ResourceSet resourceSet = aird != null ? aird.getResourceSet() : null;
-        if (resourceSet != null) {
-            // Get the fragment of the URI
-            URI repResourceURI = getURIFromExtensionPoint(representation, aird);
-            if (repResourceURI == null) {
-                repResourceURI = getRepURI(representation, aird, resourceSet);
-            }
-
-            // get or create resource
-            resource = resourceSet.getResource(repResourceURI, false);
-            if (resource == null) {
-                resource = resourceSet.createResource(repResourceURI);
-            }
-        }
-        return resource;
-    }
-
-    private URI getRepURI(DRepresentation representation, Resource aird, ResourceSet resourceSet) {
-        int count = 0;
-        URI repUri = createRepURI(aird, representation, count++);
-        while (resourceSet.getResource(repUri, false) != null) {
-            repUri = createRepURI(aird, representation, count++);
-        }
-        return repUri;
-
-    }
-
-    private URI getURIFromExtensionPoint(DRepresentation representation, Resource dViewResource) {
-        List<DRepresentationLocationRule> extensionPointRules = Lists.newArrayList();
-        extensionPointRules.addAll(EclipseUtil.getExtensionPlugins(DRepresentationLocationRule.class, DRepresentationLocationRule.ID, DRepresentationLocationRule.CLASS_ATTRIBUTE));
-
-        Optional<DRepresentationLocationRule> locationRule = extensionPointRules.stream().filter(rule -> rule.provides(representation, dViewResource)).findFirst();
-        return locationRule.isPresent() ? locationRule.get().getResourceURI(representation, dViewResource) : null;
-    }
-
-    /**
-     * Create the representation URI based on the aird resource URI. Only the last part of the segment is changed.
-     * 
-     * @param aird
-     * @param representation
-     * @param count
-     * @return
-     */
-    private URI createRepURI(Resource aird, DRepresentation representation, int count) {
-        // get the representation URI fragment
-        String repName = representation.getName().replace(' ', '_');
-        if (count > 0) {
-            repName += String.valueOf(count);
-        }
-        URI airdURI = aird.getURI();
-
-        List<String> srmFileSegments = new ArrayList<>(airdURI.segmentsList());
-        srmFileSegments.remove(srmFileSegments.size() - 1);
-        srmFileSegments.add(airdURI.lastSegment().replace("." + SiriusUtil.SESSION_RESOURCE_EXTENSION, "_aird")); //$NON-NLS-1$ //$NON-NLS-2$
-        srmFileSegments.add(repName + "." + SiriusUtil.REPRESENTATION_FILE_EXTENSION); //$NON-NLS-1$
-
-        // return the URI
-        return URI.createHierarchicalURI(airdURI.scheme(), airdURI.authority(), airdURI.device(), srmFileSegments.toArray(new String[srmFileSegments.size()]), airdURI.query(), airdURI.fragment());
-    }
-}
diff --git a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/viewpoint/SiriusPlugin.java b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/viewpoint/SiriusPlugin.java
index dbeb521e3f..7fa3e6499c 100644
--- a/plugins/org.eclipse.sirius/src/org/eclipse/sirius/viewpoint/SiriusPlugin.java
+++ b/plugins/org.eclipse.sirius/src/org/eclipse/sirius/viewpoint/SiriusPlugin.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2016 THALES GLOBAL SERVICES and others.
+ * Copyright (c) 2007, 2017 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
@@ -26,6 +26,7 @@ import org.eclipse.sirius.business.api.dialect.description.MultiLanguagesValidat
 import org.eclipse.sirius.business.internal.dialect.description.InterpretedExpressionQueryProviderRegistry;
 import org.eclipse.sirius.business.internal.helper.delete.DeleteHookDescriptorRegistryListener;
 import org.eclipse.sirius.business.internal.helper.task.ModelOperationManagerRegistryListener;
+import org.eclipse.sirius.business.internal.representation.DRepresentationLocationRuleRegistryListener;
 import org.eclipse.sirius.business.internal.resource.strategy.ResourceStrategyRegistryListener;
 import org.eclipse.sirius.business.internal.session.factory.SessionFactoryRegistryListener;
 import org.eclipse.sirius.ecore.extender.business.api.accessor.ModelAccessorsRegistry;
@@ -69,8 +70,7 @@ public final class SiriusPlugin extends EMFPlugin {
     private static Implementation plugin;
 
     /**
-     * create at the initialization to avoid synchronization cost in
-     * ExtendedPackageRegistry
+     * create at the initialization to avoid synchronization cost in ExtendedPackageRegistry
      */
     private static final ModelAccessorsRegistry REGISTRY = new ModelAccessorsRegistry();
 
@@ -110,32 +110,35 @@ public final class SiriusPlugin extends EMFPlugin {
         private InterpreterRegistry interRegistry;
 
         /**
-         * The registry listener that will be used to listen to sessionFactory
-         * extension changes.
+         * The registry listener that will be used to listen to sessionFactory extension changes.
          */
         private SessionFactoryRegistryListener sessionFactoryRegistryListener;
 
         /**
-         * 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 DeleteHookDescriptorRegistryListener deleteHookDescriptorRegistryListener;
 
         /**
-         * The registry listener that will be used to listen to contribution
-         * changes against the external java action extension point.
+         * The registry listener that will be used to listen to contribution changes against the external java action
+         * extension point.
          */
         private ExternalJavaActionRegistryListener javaActionRegistryListener;
 
         /**
-         * The registry listener that will be used to listen to contribution
-         * changes against the external resource strategy extension point.
+         * The registry listener that will be used to listen to contribution changes against the external resource
+         * strategy extension point.
          */
         private ResourceStrategyRegistryListener resourceStrategyRegistryListener;
 
         /**
-         * The registry listener that will be used to listen to contribution
-         * changes.
+         * The registry listener that will be used to listen to contribution changes against the external
+         * dRepresentationLocationRule extension point.
+         */
+        private DRepresentationLocationRuleRegistryListener repLocationRuleRegistryListener;
+
+        /**
+         * The registry listener that will be used to listen to contribution changes.
          */
         private ModelOperationManagerRegistryListener modelOperationManagerRegistryListener;
 
@@ -175,6 +178,8 @@ public final class SiriusPlugin extends EMFPlugin {
             javaActionRegistryListener.init();
             resourceStrategyRegistryListener = new ResourceStrategyRegistryListener();
             resourceStrategyRegistryListener.init();
+            repLocationRuleRegistryListener = new DRepresentationLocationRuleRegistryListener();
+            repLocationRuleRegistryListener.init();
             modelOperationManagerRegistryListener = new ModelOperationManagerRegistryListener();
             modelOperationManagerRegistryListener.init();
             expressionQueryProviderRegistry = new InterpretedExpressionQueryProviderRegistry(Platform.getExtensionRegistry(), this);
@@ -202,6 +207,8 @@ public final class SiriusPlugin extends EMFPlugin {
             javaActionRegistryListener = null;
             resourceStrategyRegistryListener.dispose();
             resourceStrategyRegistryListener = null;
+            repLocationRuleRegistryListener.dispose();
+            repLocationRuleRegistryListener = null;
             modelOperationManagerRegistryListener.dispose();
             modelOperationManagerRegistryListener = null;
             expressionQueryProviderRegistry.dispose();