content: /*******************************************************************************
   * Copyright (c) 2000, 2007 IBM Corporation 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:
   *     IBM Corporation - initial API and implementation
   *******************************************************************************/
  package org.eclipse.wst.jsdt.internal.corext.refactoring.changes;
  
  import org.eclipse.core.resources.IResourceChangeEvent;
  import org.eclipse.core.resources.IResourceChangeListener;
  import org.eclipse.core.resources.ResourcesPlugin;
  import org.eclipse.core.runtime.ListenerList;
  
  
  public class WorkspaceTracker {
  
  	public final static WorkspaceTracker INSTANCE= new WorkspaceTracker();
  	
  	public interface Listener {
  		public void workspaceChanged();
  	}
  	
  	private ListenerList fListeners;
  	private ResourceListener fResourceListener;
  	
  	private WorkspaceTracker() {
  		fListeners= new ListenerList();
  	}
  
  	private class ResourceListener implements IResourceChangeListener {
  		public void resourceChanged(IResourceChangeEvent event) {
  			workspaceChanged();
  		}
  	}
  	
  	private void workspaceChanged() {
  		Object[] listeners= fListeners.getListeners();
  		for (int i= 0; i < listeners.length; i++) {
  			((Listener)listeners[i]).workspaceChanged();
  		}
  	}
  	
  	public void addListener(Listener l) {
  		fListeners.add(l);
  		if (fResourceListener == null) {
  			fResourceListener= new ResourceListener();
  			ResourcesPlugin.getWorkspace().addResourceChangeListener(fResourceListener);
  		}
  	}
  	
  	public void removeListener(Listener l) {
  		if (fListeners.size() == 0)
  			return;
  		fListeners.remove(l);
  		if (fListeners.size() == 0) {
  			ResourcesPlugin.getWorkspace().removeResourceChangeListener(fResourceListener);
  			fResourceListener= null;
  		}
  	}
  }
  