Java设计模式—责任链模式

public abstract class Handler {
    //下一个人
    private Handler handler;
    public Handler getHandler() {
        return handler;
    }
    public void setHandler(Handler handler) {
        this.handler = handler;
    }
    /**
     * 思路：先自己处理，自己处理不了交给下一个人
     */
    public void precess(){
        doMyWork();
        if(null!=handler){
            handler.precess();
        }
    }
    /**
     * 自己的处理的抽象方法
     */
    abstract void doMyWork();
}

public class Client {
    static class HandleA extends Handler{
        @Override
        void doMyWork() {
            System.out.println("---------A处理");
        }
    }
    static class HandleB extends Handler{
        @Override
        void doMyWork() {
            System.out.println("---------B处理");
        }
    }
    static class HandleC extends Handler{
        @Override
        void doMyWork() {
            System.out.println("---------C处理");
        }
    }
    public static void main(String[] args) {
        HandleA handleA = new HandleA();
        HandleB handleB = new HandleB();
        HandleC handleC = new HandleC();
        handleA.setHandler(handleB);
        handleB.setHandler(handleC);
        handleA.precess();
    }
}

public abstract class Handler {
    /**
     * 抽象公共方法
     */
    public void precess(Chain chain){
        //自己处理
        doMyWork();
        //链式调用
        chain.exec();
    }
    /**
     * 自己处理的抽象方法
     */
    abstract void doMyWork();
}

public class Chain{
    //责任链
    private List<Handler> handlerList;
    //责任链下标
    private int index=0;
    public List<Handler> getHandlerList() {
        return handlerList;
    }
    public void setHandlerList(List<Handler> handlerList) {
        this.handlerList = handlerList;
    }
    public void exec(){
        //如果所有人都不能解决问题则返回
        if(index>=handlerList.size()){
            return;
        }
        Handler handler = handlerList.get(index);
        index++;
        handler.precess(this);
    }
}

public class Client {
    static class HandleA extends Handler {
        @Override
        void doMyWork() {
            System.out.println("---------A处理");
        }
    }
    static class HandleB extends Handler {
        @Override
        void doMyWork() {
            System.out.println("---------B处理");
        }
    }
    static class HandleC extends Handler {
        @Override
        void doMyWork() {
            System.out.println("---------C处理");
        }
    }
    public static void main(String[] args) {
        List<Handler> handlerList = Arrays.asList(
                new HandleA(),
                new HandleB(),
                new HandleC());
        Chain handler = new Chain();
        handler.setHandlerList(handlerList);
        handler.exec();
    }
}