carfield.com.hk

Button.java

2004-03-24T16:00:00Z

package examples.chainOfResponsibility.java;

/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This file is part of the design patterns project at UBC
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * either http://www.mozilla.org/MPL/ or http://aspectj.org/MPL/.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is ca.ubc.cs.spl.patterns.
 *
 * Contributor(s): 
 */
 
import javax.swing.*;
import java.awt.event.*;

/** 
 * GUI element at the start of the responsibility chain. A click on the 
 * button starts a request. The <code>Button</code> will not handle the
 * request, but pass it on to its successor. 
 *
 * @author Jan Hannemann
 * @author Gregor Kiczales
 * @version 1.0, 05/13/02
 *
 */

public class Button extends JButton implements Handler { 
	
 /**
 * the successor in the chain of responsibility
 */

	protected Handler successor;

 /** 
 * Creates a <code>Button</code> with a given label and successor. 
 *
 * @param s The button label
 * @param successor The successor in the chain of responsibility
 */	 
 
 public Button(String s, Handler successor) {
		super(s);
		this.successor = successor; 
		this.addActionListener( new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				System.out.println("\nStarting new request...");
				handleRequest();
			}
		});
	} 
	
 /** 
 * Implements the method to handle requests as defined by the
 * <code>Handler</code> interface. The request is not handled here.
 * 
 * @see Handler
 */	 
 
	public void handleRequest() {
		System.out.println("Request received by: Button (unhandled: forwarded)");
		successor.handleRequest();
	}
}

Frame.java

2004-03-24T16:00:00Z

Handler.java

2004-03-24T16:00:00Z

Main.java

2004-03-24T16:00:00Z

package examples.chainOfResponsibility.java;

/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This file is part of the design patterns project at UBC
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * either http://www.mozilla.org/MPL/ or http://aspectj.org/MPL/.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is ca.ubc.cs.spl.patterns.
 *
 * Contributor(s): 
 */
 

/**
 * Implements a GUI-motivated example for the Chain Of Rspsonsibility design
 * pattern. 
 *
 * Intent: Avoid coupling the sender of a request to its receiver by giving
 * more than one object a chance to handle the request. Chain the receiving 
 * objects and pass the request along the chain until an object handles it.
 * 
 *
 * Participatng objects are a <code>Frame</code>, a <code>Panel</code>, and 
 * <code>Button</code>
 *
 * A click on the button triggers an event (request) that gets passed along
 * the widget hierarchy (button -> panel -> frame).
 *
 * The <code>Handler</code> interface defines the <code>handleRequest()</code>
 * method for asking an object if it is willing to handle the request. 
 *
 * This is the Java version. 
 *
 * In this version, the event not handled by button and panel. Only frame 
 * handles the event.
 *
 * @author Jan Hannemann
 * @author Gregor Kiczales
 * @version 1.0, 05/13/02
 * 
 * @see Button
 * @see Panel
 * @see Frame
 * @see Handler
 */

public class Main {
	
 /**
 * Implements the driver for the chain of responisbility example. 
 * It creates a simple GUI consisting of a <code>Button</code> in a 
 * <code>Panel</code> in a <code>Frame</code>. 
 *
 * Clicking the button will start a request, that gets passed on
 * along the following chain: button, panel, frame. the frame handles 
 * the event. 
 *
 * The following messages should be observed on a buttonclick: <OL>
 * <LI> An Indication that the request was started
 * <LI> Request received by: Button (unhandled: forwarded)
 * <LI> Request received by: Panel (unhandled: forwarded)
 * <LI> Request received by: Frame (handled)
 * </UL>
 */ 

	public static void main(String[] args) { 
	 
		Frame frame = new Frame("Chain of Responsibility");
		Panel panel = new Panel(frame);
		Button button = new Button("Click me to see the Chain Of Responsibility pattern in action!", panel);
		
		frame.getContentPane().add(panel);
		panel.add(button);
		
		frame.pack();
		frame.setVisible(true);
	}
}

MyChain.java

2004-03-24T16:00:00Z

package examples.chainOfResponsibility.aspectj;



/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This file is part of the design patterns project at UBC
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * either http://www.mozilla.org/MPL/ or http://aspectj.org/MPL/.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is ca.ubc.cs.spl.patterns.
 *
 * Contributor(s):   
 */

import java.awt.event.ActionEvent; 
import ca.ubc.cs.spl.pattern.library.ChainOfResponsibilityProtocol;

/**
 * Implements an instance of the abstracted ChainOfResponsibility design
 * pattern. Here, the a click on the button triggers an event (request) 
 * that gets passed along the widget hierarchy (button -> panel -> frame). 
 * 
 * In this implementation, the request is handled by the panel if the 
 * CTRL mask is active (i.e., if the CTRL key was pressed while the button 
 * was clicked). If the SHIFT mask is active, the frame handles the request.
 * Otherwise, the request is unhandled.
 *
 * @author  Jan Hannemann
 * @author  Gregor Kiczales
 * @version 1.0, 05/13/02
 *
 */
  
public aspect MyChain extends ChainOfResponsibilityProtocol {

    /**
     * Frame, Panel and Button are all Handlers
     */

	declare parents: Frame       implements Handler;
	declare parents: Panel       implements Handler;
	declare parents: Button      implements Handler; 

    // declare parents: ActionEvent implements Object; // this would be nice! doesn't work on classes where AJ does not control the source
 
    protected pointcut eventTrigger(Handler handler, Object event): call(void Button.doClick(ActionEvent)) && target(handler) && args(event);
 

    public boolean Frame.acceptRequest(Object event) {
        if (event instanceof ActionEvent) {
            ActionEvent ae = (ActionEvent) event;
            return ((ae.getModifiers() & ActionEvent.SHIFT_MASK) != 0 );
        } 
        return false;
    } 
    
    public void Frame.handleRequest(Object event) {
		MyChain.aspectOf().note("Class "+this.getClass().getName() + " is handling the event");
    }
    
    
    public boolean Panel.acceptRequest(Object event) { 
        if (event instanceof ActionEvent) {
            ActionEvent ae = (ActionEvent) event;
            return ((ae.getModifiers() & ActionEvent.CTRL_MASK) != 0 );
        } 
        return false;
    } 
    
    public void Panel.handleRequest(Object event) {
		MyChain.aspectOf().note("Class "+this.getClass().getName() + " is handling the event");
    }


}

Panel.java

2004-03-24T16:00:00Z

files.lst

2004-03-24T16:00:00Z