责任链模式--行为模式

适用场景如下:

springmvc中的拦截器就用了责任链模式

UML图如下:

其中最为关键位handle类

代码如下:

public abstract class Handle {

    protected String name;

    protected Handle nextHandle;

    public void setName(String name) {
        this.name = name;
    }

    public void setNextHandle(Handle nextHandle) {
        this.nextHandle = nextHandle;
    }

    protected abstract void  hand(HandRequest request);

    protected abstract boolean  isHand(HandRequest request);

    protected  void  handFun(HandRequest request){
        if(this.isHand(request)){
            this.hand(request);
        }else {
            System.out.println(this.name+"处理不了,让"+nextHandle.name+"处理");
            nextHandle.handFun(request);
        }
    }
}

AHandle类

public class AHandle extends Handle {

    @Override
    protected void hand(HandRequest request) {
        System.out.println("我是A,正在处理:"+request.getDay());
    }

    @Override
    protected boolean isHand(HandRequest request) {
        if(request.getDay()>10){
            return false;
        }
        return true;
    }
}

Client类调用

public static void main(String[] args) {
    Handle aHandle = new AHandle();
    aHandle.setName("a");
    Handle bHandle = new BHandle();
    bHandle.setName("b");
    Handle cHandle = new CHandle();
    cHandle.setName("c");

    //构件责任链
    aHandle.setNextHandle(bHandle);
    bHandle.setNextHandle(cHandle);

    //处理A
    HandRequest handRequestA = new HandRequest(1);
    aHandle.handFun(handRequestA);

    System.out.println("=========================");

    //处理B
    HandRequest handRequestB = new HandRequest(11);
    aHandle.handFun(handRequestB);

    System.out.println("=========================");
    //处理C
    HandRequest handRequestC = new HandRequest(111);
    aHandle.handFun(handRequestC);

结果效果如下: