watched.java

来自「《JAVA与模式》附书中源代码」· Java 代码 · 共 25 行

package com.javapatterns.observer.watching;

import java.util.Observable;

public class Watched extends Observable
{
    private String data = "";

    public String retrieveData()
    {
		return data;
    }

    public void changeData(String data)
    {
        if ( !this.data.equals( data) )
        {
            this.data = data;
            setChanged();
        }

        notifyObservers();
    }
}