代理模式和回调函数

package callback;
public interface CallBack {
    void execute();
}

package callback;
public class MyCallBack implements CallBack {
    @Override
    public void execute() {
        testMethod();
    }
    public   static   void  testMethod(){
        for (int  i= 0 ; i< 100000000 ; i++){

        }
    }
}

package callback;
// 代理类
public class Proxy implements CallBack {
    private MyCallBack callBack;
    public Proxy(MyCallBack callBack) {
        this.callBack = callBack;
    }

    @Override
    public void execute() {
        callBack.execute();
    }
}

package callback;

public class RunningTime {
    public static void testMethod(){
        for (int i = 0; i < 100000; ++i) {
            System.out.print("i:" + i);
        }
        System.out.println();
    }

    public void testTime() {
        long begin = System.currentTimeMillis();
        testMethod();
        long end = System.currentTimeMillis();
        System.out.println("cost time:" + (end - begin));
    }

    public static void main(String[] args) {
        RunningTime test = new RunningTime();
        test.testTime();
        System.out.println("ok");
    }
}

package callback;

public class Tools {

    public void testTime (CallBack callBack) {
        long start = System.currentTimeMillis();
        callBack.execute();
        long end = System.currentTimeMillis();
        System.out.println("cost time: " + (end - start));
    }

    public static void main(String[] args) throws InterruptedException {
        /**Tools tools = new Tools();
        tools.testTime(() -> RunningTime.testMethod()); // n=100执行时间9ms,时间长之后近似
        Thread.sleep(1000);
        tools.testTime(new CallBack() { // n=100 cost 2ms
            @Override
            public void execute() {
                RunningTime.testMethod();
            }
        });
        System.out.println("hhh, ok!");**/
        Tools tools = new Tools();
        // 代理类实现调用
        Proxy proxy = new Proxy(new MyCallBack());
        tools.testTime(proxy);
    }
}

区别：
1 代理模式需要创建接口实现类，并放入代理类中隔离性能好，扩展性好。
2 回调函数不需要创建接口实现类, 编写方便。

参考：
1 java 回调函数例子，及其原理，与代理模式的区别