/**
	 * Loads the diagram (typically delegating on the diagram provider), 
	 * If the loading is successfull, the listeners will be registered
	 * and the object will be ready for use.
	 * In case of error an exception will be thrown - and this object should be
	 * discarded by the caller.
         * The domain should be used if not null, elsewhere a new domain should be created.
	 * The editor will call this method only at initialization (init)
	 * but the object might call it internally for diagram reloading, if supported.
	 */
	public abstract void loadDiagram(IEditorInput input, TransactionalEditingDomain domain);

	/**
	 * This is for implementing {@link IEditorPart} and simply saves the model file.
	 * 
	 * @param progressMonitor
	 *            The {@link IProgressMonitor} progress monitor
	 */
	public abstract void doSave(IProgressMonitor progressMonitor);

	/**
	 * Unregisters listeners and dispose domain (if it should)
	 * The object should not be usable after this is called. 
	 */
	public void dispose();

	/**
	 * Returns null only if the diagram is still not loaded or if it's disposed
	 */
	public Diagram getDiagram();

	public TransactionalEditingDomain getEditingDomain();