undoablejcheckbox.java

来自「《java事件处理指南》一书的代码,好东西」· Java 代码 · 共 51 行

import javax.swing.*;
import java.awt.event.*;
import javax.swing.event.*;
import javax.swing.undo.*;

public class UndoableJCheckBox extends JCheckBox
{
/*  The UndoableJCheckBox class uses an UndoableEditSupport object  */
/*  to provide an undoable capability to a JCheckBox.               */

   private UndoableEditSupport undoSupport;

/*  The constructor calls the JCheckBox constructor and then       */
/*  initializes the UndoableEditSupport object.  The event source  */
/*  is set to be the UndoableJCheckBox object.                     */

   public UndoableJCheckBox(String title) 
   {
      super(title);
      undoSupport = new UndoableEditSupport(this);
   }

/*  The UndoableEditSupport object is used to implement the methods       */
/*  to add or remove an UndoableEditListener from the UndoableJCheckBox.  */

   public void addUndoableEditListener(UndoableEditListener listener)
   {
      undoSupport.addUndoableEditListener(listener);
   }

   public void removeUndoableEditListener(UndoableEditListener listener)
   {
      undoSupport.removeUndoableEditListener(listener);
   }

/*  The fireActionPerformed() method is overridden so that when the mouse  */
/*  is pressed over the UndoableJCheckBox, an UndoableJCheckBoxEdit object */
/*  is created and sent to any registered UndoableEditListeners.           */

   protected void fireActionPerformed(ActionEvent event)
   {
      super.fireActionPerformed(event);

      undoSupport.postEdit(new UndoableJCheckBoxEdit(this));
   }

}