模擬Button監聽

package com.zhijun.test;

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

public class TestButton {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Button b = new Button();
		b.addActionListener(new MyActionListener());
		b.buttonPressed();
	}

}


class Button {
	private List<ActionListener> actionListeners = new ArrayList<ActionListener>();
	
	public void buttonPressed() {
		ActionEvent e = new ActionEvent();
		
		for(int i=0; i<actionListeners.size(); i++) {
			ActionListener l = actionListeners.get(i);
			l.actionPerformed(e);
		}
	}
	
	public void addActionListener(ActionListener l) {
		actionListeners.add(l);
	}
}

interface ActionListener {
	public void actionPerformed(ActionEvent e);
}

class MyActionListener implements ActionListener {

	@Override
	public void actionPerformed(ActionEvent e) {
		// TODO Auto-generated method stub
		System.out.println("button pressed!");
	}

	
}

class ActionEvent {
	public long getWhen() {
		return System.currentTimeMillis();
	}
}