设计模式：责任链方式

设计模式：责任链模式

?2、实例代码

package com.leon.chain;public abstract class Chain {public static int One = 1;public static int Two = 2;public static int Three = 3;protected int threshold;protected Chain next;public void setNext(Chain chain) {this.next = chain;}public void message(String msg, int priority) {if (priority <= threshold) {writeMessage(msg);}if (this.next != null) {this.next.message(msg, priority);}}abstract void writeMessage(String msg);}

?

package com.leon.chain;public class Test {public static void main(String[] args) {Chain chain = createChain();chain.message("level 3", Chain.Three);chain.message("level 2", Chain.Two);chain.message("level 1", Chain.One);}public static Chain createChain() {Chain chain1 = new A(Chain.Three);Chain chain2 = new B(Chain.Two);chain1.setNext(chain2);Chain chain3 = new C(Chain.One);chain2.setNext(chain3);return chain1;}}class A extends Chain {public A(int threshold) {this.threshold = threshold;}@Overridevoid writeMessage(String msg) {// TODO Auto-generated method stubSystem.out.println("A:"+msg);}}class B extends Chain {public B(int threshold) {this.threshold = threshold;}@Overridevoid writeMessage(String msg) {// TODO Auto-generated method stubSystem.out.println("B:"+msg);}}class C extends Chain {public C(int threshold) {this.threshold = threshold;}@Overridevoid writeMessage(String msg) {// TODO Auto-generated method stubSystem.out.println("C:"+msg);}}

?在这个例子中，level 1的Message走过了链中所有的单元。

?原文链接：这里