设计模式_责任链模式

责任链模式的重点是在“链”上。由一条链去处理相似的请求在链中决定谁来处理这个请求，并返回对应的结果，其通用类图如图16-4所看到的。

最核心的东西★

<span style="font-family:Microsoft YaHei;">public abstract class Handler {
 public final static int FATHER=1;
 public final static int HUSBAND=2;
 public final static int SON=3;
 private int level=0;
 private Handler nextHandler;  //这是重点

 public Handler(int _level){
  this.level=_level;
 } 
 
 public final void HandlerMessage(IWomen women){
  if(women.getType()==this.level){	
   this.response(women);
  }else{
   if(this.nextHandler != null){
    this.nextHandler.HandlerMessage(women);
   }else{
    System.out.println("没有兴许。就是不允许");
   }
  }
 }
 
 public void setNext(Handler _nextHandler){
  this.nextHandler=_nextHandler;
  
 }
 
 protected abstract void response(IWomen women);
}</span>

<span style="font-family:Microsoft YaHei;font-size:12px;">public class Father extends Handler {

 public Father() {
  super(Handler.FATHER);
 }

 @Override
 protected void response(IWomen women) {
  System.out.println("女儿向父亲请示:"+women.getRequest());
  System.out.println("父亲答应");
 }
}</span>

<span style="font-family:Microsoft YaHei;font-size:12px;">public class Husband extends Handler{

 public Husband() {
  super(Handler.HUSBAND);
 }

 @Override
 protected void response(IWomen women) {
  System.out.println("妻子的请示:"+women.getRequest());
  System.out.println("丈夫准许了");
 }
}</span>

public class Son extends Handler {

 public Son() {
  super(Handler.SON);
 }

 @Override
 protected void response(IWomen women) {
  System.out.println("母亲的请示是"+women.getRequest());
  System.out.println("儿子准许了");
 }
}

<span style="font-family:Microsoft YaHei;font-size:12px;">public interface IWomen {

 public int getType();

 public String getRequest();

}</span>

<span style="font-family:Microsoft YaHei;font-size:12px;">public class Women implements IWomen {

 /* 0:未出嫁
  * 1:已出嫁
  * 2:丧夫
  */
 private int type=0;
 private String request="";
 
 public Women(int type,String request){
 
  this.type=type;
  this.request=request;
 }
 
 public String getRequest() {
  return this.request;
 }

 public int getType() {
  return this.type;
 }
}</span>

<span style="font-family:Microsoft YaHei;font-size:12px;">public class Client {

 public static void main(String[] args) {
  Random random=new  Random();
  ArrayList<IWomen> list=new ArrayList<IWomen>();
  for(int i=0;i<5;i++){
   list.add(new Women(random.nextInt(4),"我要出去逛街"));
  //产生随机的类型
  }
  Handler father=new Father();
  Handler husband=new Husband();
  Handler son=new Son();
  father.setNext(husband);
   //设置下一个
  husband.setNext(son);
      //设置下一个
  for(IWomen women:list){
          
   father.HandlerMessage(women);  //当然从最高開始
  }
 }
}
/**
 * 重要是"链"，由一条链去处理类似的请求在链中决定谁来处理这个请求
 */</span>

悟 

这个设计模式一个最大的特点就是setNext()方法。能够往后传递从而实现递归一样的循环，假设这个不行，那就给下一个。链式结构的遍历。 "链"，类似于if-else。显然这个设计的更高级，更工整。假设要说扩展性的话，那么还行吧。毕竟一个系统不可能有非常长的责任链吧。能够和其它模式联合使用，关键还是场景，需求的问题。

我是菜鸟，我在路上。