责任链模式

简介：

责任链模式通俗点讲就是，打开层次箱子，最终发现真正的珠宝。

模式：

1.假设层层箱子分别为A、B、C、D，珠宝为X。

2.先将X放在D中，那么D认为X是珠宝；在把D放在C中，那么C认为D是珠宝；再把C放在B中，那么B认为C是珠宝；再把B放在A中，那么A认为B是珠宝。

3.执行A-B-C-D-X.

代码：

1.箱子抽象为接口

package com.bluejie.bluej.java.design.chain;

import com.bluejie.bluej.logUtil.LogUtil;
import org.slf4j.Logger;

/**
 * Created by bluej on 2018/2/1.
 */
public interface Handler {

    Logger log = LogUtil.instance(Handler.class);

    void doHandle(Executor executor);
}

  

2.各层箱子实现类

package com.bluejie.bluej.java.design.chain;

/**
 * Created by bluej on 2018/2/1.
 */
public class LogHandler implements Handler {
    @Override
    public void doHandle(Executor executor) {
        log.info("--LogHandler--");
        executor.doExecutor();
    }
}

package com.bluejie.bluej.java.design.chain;

/**
 * Created by bluej on 2018/2/1.
 */
public class ParamaterHandler implements Handler {
    @Override
    public void doHandle(Executor executor) {
        log.info("--ParamaterHandler--");
        executor.doExecutor();
    }
}

package com.bluejie.bluej.java.design.chain;

/**
 * Created by bluej on 2018/2/1.
 */
public class ServiceHandler implements Handler {
    @Override
    public void doHandle(Executor executor) {
        log.info("--ServiceHandler--");
        executor.doExecutor();
    }
}

3.珠宝抽象为接口

package com.bluejie.bluej.java.design.chain;

import com.bluejie.bluej.logUtil.LogUtil;
import org.slf4j.Logger;

/**
 * Created by bluej on 2018/2/1.
 */
public interface Executor {
    Logger log = LogUtil.instance(Executor.class);

    void doExecutor();
}

4.珠宝实现类

package com.bluejie.bluej.java.design.chain;

/**
 * Created by bluej on 2018/2/1.
 */
public class ExecutorService implements Executor {
    @Override
    public void doExecutor() {
        log.info("--ExecutorService--");
    }
}

5.执行demo

package com.bluejie.bluej.java.design.chain;


import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

/**
 * Created by bluej on 2018/2/1.
 */
public class ChainDemo {
    private static ChainDemo chainDemo =new ChainDemo();

    public static void main(String[] args) {
        chainDemo.execute().doExecutor();
    }

    private Executor execute(){

        Executor executor = new ExecutorService();
        List<Handler> handleList  = new ArrayList<>();
        handleList.add(new LogHandler());
        handleList.add(new ParamaterHandler());
        handleList.add(new ServiceHandler());
        Collections.reverse(handleList);

        for (int i = 0 ;i<handleList.size(); i++) {
            System.out.println(i);
            final  Handler handle = handleList.get(i);
            final Executor executorAgain = executor;
            executor = new Executor() {
                @Override
                public void doExecutor() {
                    handle.doHandle(executorAgain);
                }
            };
        }
        return executor;

    }

}

6.执行结果

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2018-02-02 00:33:29,270 [main] INFO  com.bluejie.bluej.java.design.chain.Handler.doHandle   - --LogHandler--
2018-02-02 00:33:29,276 [main] INFO  com.bluejie.bluej.java.design.chain.Handler.doHandle   - --ParamaterHandler--
2018-02-02 00:33:29,276 [main] INFO  com.bluejie.bluej.java.design.chain.Handler.doHandle   - --ServiceHandler--
2018-02-02 00:33:29,276 [main] INFO  com.bluejie.bluej.java.design.chain.Executor.doExecutor - --ExecutorService--