职责链模式 Chain of Responsibility

package chainofres;

public abstract class Handler {
protected Handler successor;

public abstract void action(int request);

public void setSuccessor(Handler successor) {
this.successor = successor;
}
}

package chainofres;

public class ConcurrentHandler1 extends Handler {
@Override
public void action(int request) {
if (request < 100)
System.out.println("Handler1 handle this");
else if (this.successor != null)
this.successor.action(request);
}
}

package chainofres;

public class ConcurrentHandler2 extends Handler {
@Override
public void action(int request) {
if (request >= 100 && request < 1000)
System.out.println("Handler2 handle this");
else if (this.successor != null)
this.successor.action(request);
}
}

package chainofres;

public class ConcurrentHandler3 extends Handler {
@Override
public void action(int request) {
if (request >= 1000)
System.out.println("Handler3 handle this");
else if (this.successor != null)
this.successor.action(request);
}
}

package chainofres;

public class Client {
public static void main(String[] args) {
Handler h1 = new ConcurrentHandler1();
Handler h2 = new ConcurrentHandler2();
Handler h3 = new ConcurrentHandler3();
h1.setSuccessor(h2);
h2.setSuccessor(h3);

int request = 50;
h1.action(request);
request = 200;
h1.action(request);
request = 1500;
h1.action(request);
}
}