1 package com.cnblogs.vicentzh.strategymodel;
  2 
  3 import java.util.ArrayList;
  4 import java.util.Collections;
  5 import java.util.Comparator;
  6 import java.util.Iterator;
  7 import java.util.List;
  8 
  9 public class StrategyModel
 10 {
 11     /**
 12      * @Describe 客户端程序
 13      * @param args
 14      */
 15     public static void main(String[] args)
 16     {
 17         Student p1 = new Student("Tom",1,20);
 18         Student p2 = new Student("Tonny",2,50);
 19         Student p3 = new Student("Tom",5,30);
 20         Student p4 = new Student("John",8,10);
 21         Student p5 = new Student("Susan",9,15);
 22 
 23         List<Student> students = new ArrayList<Student>();
 24         students.add(p1);
 25         students.add(p2);
 26         students.add(p3);
 27         students.add(p4);
 28         students.add(p5);
 29 
 30         Context env = new Context();
 31 
 32         //正序排列
 33         UpNameSort uns = new UpNameSort();
 34         env.setSortStrategy(uns);
 35         env.sort(students);
 36 
 37         for (Iterator<Student> iter=students.iterator(); iter.hasNext();)
 38         {
 39             Student student = iter.next();
 40             System.out.println("id: " + student.getId() + ", name: " + student.getName()
 41                     + ", age:" + student.getAge());
 42         }
 43         System.out.println("-----------------------");
 44         
 45         //倒序排列
 46         DownNameSort dns = new DownNameSort();
 47         env.setSortStrategy(dns);
 48         env.sort(students);
 49 
 50         for (Iterator<Student> iter=students.iterator(); iter.hasNext();)
 51         {
 52             Student student = iter.next();
 53             System.out.println("id: " + student.getId() + ", name: " + student.getName()
 54                     + ", age:" + student.getAge());
 55         }
 56 
 57     }    
 58 }
 59 
 60 
 61 //需要用到的具体实例类
 62 class Student
 63 {
 64     private String name;
 65     private int age;
 66     private int id;
 67     
 68     public Student(String name, int age, int id)
 69     {
 70         this.name = name;
 71         this.age = age;
 72         this.id = id;
 73     }
 74     
 75     public String getName()
 76     {
 77         return name;
 78     }
 79     public int getAge()
 80     {
 81         return age;
 82     }
 83     public int getId()
 84     {
 85         return id;
 86     }    
 87 }
 88 
 89 
 90 //抽象策略类(Strategy)，即策略接口
 91 interface SortStrategy
 92 {
 93     public void sortStudent(List<Student> students);
 94 }
 95 
 96 
 97 //具体策略类(ConcreteStrategy),即具体正序算法实现类
 98 class UpNameSort implements SortStrategy,Comparator<Student>
 99 {
100     @Override
101     public void sortStudent(List<Student> students)
102     {
103         Collections.sort(students, this);
104     }
105     
106     @Override
107     public int compare(Student o1, Student o2)
108     {
109         int result = o1.getName().compareTo(o2.getName());
110         if(0==result)
111         {
112             return o1.getId() - o2.getId();
113         }
114         return result;
115     }
116 }
117 
118 //具体策略类(ConcreteStrategy),即具体倒序算法实现类
119 class DownNameSort implements SortStrategy, Comparator<Student>
120 {
121     @Override
122     public void sortStudent(List<Student> students)
123     {
124         Collections.sort(students, this);
125         
126     }
127     
128     @Override
129     public int compare(Student o1, Student o2)
130     {
131         int result = o2.getName().compareTo(o1.getName());
132         if(0==result)
133         {
134             return o1.getId() - o2.getId();
135         }
136         return result;
137     }
138 }
139 
140 //使用环境类(Context)
141 //环境类根据接收到客户端具体的策略来对对象进行使用，同样也能用setSortStrategy方法
142 //随时根据客户端的需求去改变策略算法，并且不影响对象。
143 class Context
144 {
145     private SortStrategy concreteStrategy; //使用策略配置环境类
146     
147     public Context(SortStrategy conSortStrategy)
148     {
149         this.concreteStrategy = conSortStrategy;
150     }
151     
152     public Context()
153     {
154         
155     }
156     
157     //可随意定制化具体策略
158     public void setSortStrategy(SortStrategy conSortStrategy)
159     {
160         this.concreteStrategy = conSortStrategy;
161     }
162     
163     //使用具体的策略(concreteStrategy)对对象进行操作
164     public void sort(List<Student> students)
165     {
166         concreteStrategy.sortStudent(students);
167     }
168 }