责任链模式

Posted 2021-02-01 linbq1911

1.定义：为请求创建一个接收此次请求对象的链

2.类型：行为型

3.适用场景：一个请求的处理需要多个对象当中的一个或几个协作处理。

4.优点：请求的发送者和接收者(请求的处理)解耦；责任链可以动态组合。

5.缺点：责任链太长或者处理时间过长，影响性能；责任链有可能过多。

6.相关设计模式：状态模式。

7.实例目录package

8.实例UML类图

9.代码

 1 package com.geely.design.pattern.behavioral.chainofresponsibility;
 2 
 3 public class Course {
 4     private String name;
 5     private String article;
 6     private String video;
 7 
 8     public String getName() {
 9         return name;
10     }
11 
12     public void setName(String name) {
13         this.name = name;
14     }
15 
16     public String getArticle() {
17         return article;
18     }
19 
20     public void setArticle(String article) {
21         this.article = article;
22     }
23 
24     public String getVideo() {
25         return video;
26     }
27 
28     public void setVideo(String video) {
29         this.video = video;
30     }
31 
32     @Override
33     public String toString() {
34         return "Course{" +
35                 "name=‘" + name + ‘‘‘ +
36                 ", article=‘" + article + ‘‘‘ +
37                 ", video=‘" + video + ‘‘‘ +
38                 ‘}‘;
39     }
40 }

 1 package com.geely.design.pattern.behavioral.chainofresponsibility;
 2 
 3 public abstract class Approver {
 4     protected Approver approver;
 5 
 6     public void setNextApprover(Approver approver){
 7         this.approver = approver;
 8     }
 9     public abstract void deploy(Course course);
10 }

 1 package com.geely.design.pattern.behavioral.chainofresponsibility;
 2 
 3 import org.apache.commons.lang.StringUtils;
 4 
 5 public class VideoApprover extends Approver {
 6     @Override
 7     public void deploy(Course course) {
 8         if(StringUtils.isNotEmpty(course.getVideo())){
 9             System.out.println(course.getName() + "含有视频，批准");
10             if(approver != null){
11                 approver.deploy(course);
12             }
13         }else{
14             System.out.println(course.getName() + "不含有视频，不批准");
15             return;
16         }
17     }
18 }

 1 package com.geely.design.pattern.behavioral.chainofresponsibility;
 2 
 3 import org.apache.commons.lang.StringUtils;
 4 
 5 public class ArticleApprover extends Approver {
 6     @Override
 7     public void deploy(Course course) {
 8         if(StringUtils.isNotEmpty(course.getArticle())){
 9             System.out.println(course.getName() + "含有手记，批准");
10             if(approver != null){
11                 approver.deploy(course);
12             }
13         }else{
14             System.out.println(course.getName() + "不含有手记，不批准");
15             return;
16         }
17     }
18 }

 1 package com.geely.design.pattern.behavioral.chainofresponsibility;
 2 
 3 public class Test {
 4     public static void main(String[] args) {
 5         Approver articleApprover = new ArticleApprover();
 6         Approver videoApprover = new VideoApprover();
 7         Course course = new Course();
 8         course.setName("Java设计模式精讲 -- By Geely");
 9         course.setArticle("Java设计模式精讲的手记");
10         course.setVideo("Java设计模式精讲的视频");
11 
12         articleApprover.setNextApprover(videoApprover);
13         articleApprover.deploy(course);
14     }
15 }