[1301] Add support to create a JSON resource with the right scheme

Bug: #1301
Signed-off-by: Laurent Fasani <laurent.fasani@obeo.fr>

backend/sirius-components-emf/src/main/java/org/eclipse/sirius/components/emf/services/EditingContext.java

@@ -24,6 +24,12 @@
  */
 public class EditingContext implements IEditingContext {
 
+    /**
+     * This scheme should be used to create an URI of a resource that corresponds to a document added in the
+     * EditingContext ResourceSet.
+     */
+    public static final String RESOURCE_SCHEME = "sirius"; //$NON-NLS-1$
+
     private final String id;
 
     private final AdapterFactoryEditingDomain editingDomain;

backend/sirius-components-emf/src/main/java/org/eclipse/sirius/components/emf/services/JSONResourceFactoryImpl.java

@@ -37,4 +37,17 @@ public JsonResource createResource(URI uri) {
 
         return new JsonResourceImpl(uri, options);
     }
+
+    /**
+     * Create a resource which URI is made of a correct scheme and the given id as path.
+     *
+     * @param resourceId
+     *            the id of the resource
+     */
+    public JsonResource createResource(String resourceId) {
+        // There are three slashes because the URI authority is empty
+        URI uri = URI.createURI(EditingContext.RESOURCE_SCHEME + ":///" + resourceId); //$NON-NLS-1$
+
+        return this.createResource(uri);
+    }
 }