observablesupport.java

基于Eclipse RCP开发的管理工具

 /*  
  * Copyright 2006 Marcel Schoffelmeer 
  * 
  * Licensed under the Apache License, Version 2.0 (the "License"); 
  * you may not use this file except in compliance with the License. 
  * You may obtain a copy of the License at 
  * 
  *    http://www.apache.org/licenses/LICENSE-2.0 
  *    
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

package com.s10r.util;

import java.util.ArrayList;
import java.util.List;


/**
 * Utility class for model classes to add observable support through
 * containment. Having model classes inherit from this class is not advised as
 * the contained methods are generic (e.g. add/remove etc): Employee.add: it is
 * not clear that this involves adding an observer. Employee.addObserver through
 * containment is a better approach.
 * 
 * @author SCHOFFEM
 * 
 */
public class ObservableSupport
{
	protected List<Observer> observers = new ArrayList<Observer>();

	public ObservableSupport()
	{
		super();
	}

	public void add(Observer o)
	{
		if (!contains(o))
		{
		   observers.add(o);
		}
	}
	
	public boolean contains(Observer o)
	{
		return observers.contains(o);
	}
	
	public void remove(Observer o)
	{
		observers.remove(o);
	}

	public void clear()
	{
		observers.clear();
	}

	public void notify(UpdateEvent event)
	{
		for (Observer observer : observers)
		{
			observer.update(event);
		}
	}
	
	public void notifyEdit(Object obj)
	{
		notify(UpdateEvent.Type.EDIT, obj);
	}

	public void notify(UpdateEvent.Type type, Object obj)
	{
		notify(new UpdateEvent(type, obj));		
	}

}