23种设计模式之责任链模式

责任链模式（Chain Of Responsibility）：使多个对象都有机会处理请求，从而避免请求的发送者和接收者之间的耦合关系。将这个对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理它为止。

 

package designMode.chainOfResponsibility;

abstract class Handler {
    
    protected Handler successor;

    public void setSuccessor(Handler successor) {
        this.successor = successor;
    }
    
    public abstract void handleRequest(int request);
}

package designMode.chainOfResponsibility;

class ConcreteHandler1 extends Handler{

    @Override
    public void handleRequest(int request) {
        if(request>=0 && request<10)
            System.out.println("处理0到9的请求！");
        else if(successor != null)
            successor.handleRequest(request);
    }
}
class ConcreteHandler2 extends Handler{
    
    @Override
    public void handleRequest(int request) {
        if(request>=10 && request<20)
            System.out.println("处理10到19的请求！");
        else if(successor != null)
            successor.handleRequest(request);
    }
}
class ConcreteHandler3 extends Handler{
    
    @Override
    public void handleRequest(int request) {
        if(request>=20 && request<30)
            System.out.println("处理20到29的请求！");
        else if(successor != null)
            successor.handleRequest(request);
    }
}

package designMode.chainOfResponsibility;

class Test {
    public static void main(String[] args) {
        Handler h1 = new ConcreteHandler1();
        Handler h2 = new ConcreteHandler2();
        Handler h3 = new ConcreteHandler3();
        h1.setSuccessor(h2);
        h2.setSuccessor(h3);
        int[] requests = {2,5,14,22,18,3,27,20};
        for (int i : requests) {
            h1.handleRequest(i);
        }
    }
}