java双重委派

package com.djk.design.action.shuangchong;

public interface A 
{
	void doSome(B b);
	
	void say();
}

package com.djk.design.action.shuangchong;

public interface B 
{
	void doB(A a);
}

package com.djk.design.action.shuangchong;

public class AImpl implements A
{

	@Override
	public void doSome(B b) {
		b.doB(this);
	}

	@Override
	public void say() 
	{
		System.out.println("我被回调了啊");
	}

}

package com.djk.design.action.shuangchong;

public class BImpl implements B 
{
	@Override
	public void doB(A a) 
	{
		System.out.println("我完成了 准备回调");
		a.say();
	}
}

package com.djk.design.action.shuangchong;

public class Client
{
	public static void main(String[] args) 
	{
		A a = new AImpl();
		B b = new  BImpl();
		
		a.doSome(b);
	}
}