Java回调机制的实现方式

Java回调机制的实现方式
http://blog.chinaunix.net/uid-26727976-id-3130486.html
一、回调机制在java中应用非常广泛，下面用一个demo简单的实现回调机制
1.Time.java
package com.test;
public class Time {
    private OnTimeChange mOnTimeChange;
    private int time;
/*接口*/
    public interface OnTimeChange{
        public void timChange();
    }
/*监听事件*/
    public void setOnTimeChangeListener(OnTimeChange change){
        mOnTimeChange=change;
    }
    public void setTime(int value){
         time=value;
        mOnTimeChange.timChange();
    }
}
2.Caller.java
public class Caller extends Activity implements OnTimeChange {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Time time=new Time();
        time.setOnTimeChangeListener(this);//监听事件
        time.setTime(1);
/*匿名内部类实现接口*/   
time.setOnTimeChangeListener(new OnTimeChange() {
            
            @Override
            public void timChange() {
                // TODO Auto-generated method stub
                Log.i("debug", "time has changed");
            }
        });
    }
    @Override
    public void timChange() {
        // TODO Auto-generated method stub
        Log.i("debug", "Time has changed");
    }
}


二、
public class Test{
   public static void main(String[] args){
     FooBar foo=new FooBar();
     foo.setCallBack(new ICallBack(){
        public void postExec(){System.out.println("method executed.");}
     });
   }
}


aaaaaa
public interface ICallBack(){
  void postExec();
}


bbbbbb
public class FooBar..{
  private ICallBack callBack;
  public void setCallBack(ICallBack callBack){
    this.callBack=callBack;
  }
  public void doSth(){
     ....
     callBack.postExec();
  }
  ..
}

JAVA的CALLBACK通过接口来实现。  
  例：  
  1.class   A,class   B  
  2.class   A实现接口ICallBack  
  3.class   B拥有一个参数为ICallBack接口类型的函数setCallBack(ICallBack   o)  
  4.class   A运行时调用class   B中setCallBack函数,以自身传入参数  
  5.class   B已取得A，就可以随时回调A所实现的ICallBack接口中的方法