itsukyuquotation.java

java与模式 一书的源码

package com.javapatterns.command.itsukyu;

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

class ItsukyuQuotation extends Panel implements ActionListener
{
    /**
     * @link aggregation 
     */
    private final Command undo ;

    /**
     * @link aggregation 
     */
    private final Command redo ;

    // Constructor
    public ItsukyuQuotation(UndoableTextArea text)
    {

        setLayout(new BorderLayout());

        // create a toolbar for buttons
        Panel toolbar = new Panel();

        // create undo and redo buttons
        // add listeners for buttons
        undo = new UndoCommand(text);
        redo = new RedoCommand(text);

        undo.addActionListener (this);
        
        redo.addActionListener (this);

        // add buttons to toolbar
        toolbar.add(undo);
        toolbar.add(redo);

        // add toolbar and text area to panel
        add(toolbar, "North");
        add(text, "Center");
    }
	 //-----------------------------------------
	public void actionPerformed(ActionEvent e)
	{
		Command cmd = (Command)e.getSource();
		cmd.execute();
	}

}