added convenience method for unique ID preparation

org.fortiss.tooling.kernel/trunk/src/org/fortiss/tooling/kernel/utils/ModelUtils.java

@@ -40,4 +40,16 @@ public class ModelUtils {
 		topLevel.runAsCommand(command);
 	}
 
+	/**
+	 * Assigns unique IDs to the given target model element.
+	 * 
+	 * @param context
+	 *            a model element already contained in a persisted model
+	 * @throws NullPointerException
+	 *             if the context is not contained in a persisted model
+	 */
+	public static void prepareUniqueID(EObject element, EObject context) {
+		IPersistencyService.INSTANCE.getTopLevelElementFor(context).prepareIDs(
+				element);
+	}
 }