defaultmodel.java

来自「Novocode的 SWT 控件框架 丰富了MDI功能」· Java 代码 · 共 60 行

/*******************************************************************************
 * Copyright (c) 2004 Stefan Zeiger 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.novocode.com/legal/epl-v10.html
 * 
 * Contributors:
 *     Stefan Zeiger ([e-mail]) - initial API and implementation
 *******************************************************************************/

package com.novocode.naf.model;

import java.util.*;

import com.novocode.naf.gui.event.*;


/**
 * Default implementation of the IModel interface.
 * 
 * @author Stefan Zeiger ([e-mail])
 * @since Jan 3, 2004
 */

public abstract class DefaultModel implements IModel
{
  private List<IChangeListener> listeners;
  private ChangeEvent changeEvent = new ChangeEvent(this);


  public final synchronized void addChangeListener(IChangeListener listener)
  {
    if(listeners == null) listeners = new ArrayList<IChangeListener>();
    listeners.add(listener);
  }


  public final synchronized void removeChangeListener(IChangeListener listener)
  {
    if(listeners == null) return;
    listeners.remove(listener);
  }
  
  
  protected final synchronized void notifyListeners()
  {
    notifyListeners(changeEvent);
  }
  
  
  protected final synchronized void notifyListeners(ChangeEvent event)
  {
    if(listeners == null) return;
    // Listeners list may be changed in a stateChanged() call, so we need to make a copy first
    IChangeListener[] copy = listeners.toArray(new IChangeListener[listeners.size()]);
    for(int i=0; i<copy.length; i++) copy[i].stateChanged(event);
  }
}