享元模式

Author: mirsfang

README.md

@@ -28,7 +28,7 @@
 * 观察者模式
 * 责任链模式
 * 原型模式
-
+* 享元模式
 
 
 
@@ -39,4 +39,7 @@
 ## 一些模式的截图
 ![Markdown](http://p1.bqimg.com/1949/f20c478905397ed2.png)
 ![Markdown](http://p1.bqimg.com/1949/0121ae17beee2397.png)
+
+
+
 交流群：38240957

src/structure/flyweight/ConcreateFlyweight_1.java

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+package structure.flyweight;/**
+ * Created by MirsFang on 2017/3/9.
+ */
+
+import structure.flyweight.flyweightAbs.Flyweight;
+
+import java.util.Random;
+
+/***
+ *作者：MirsFang    
+ *模式：享元模式
+ *时间：2017/03/09/下午12:35  
+ *备注  具体享元对象
+ ***/
+
+public class ConcreateFlyweight_1 extends Flyweight{
+
+    //接受外部状态
+    public ConcreateFlyweight_1(String extrinsic) {
+        super(extrinsic);
+    }
+
+    //根据外部状态进行逻辑处理
+    @Override
+    public void operate() {
+        System.out.println(Extrinsic+"订单,订单编号"+new Random().nextInt(99999));
+    }
+}

src/structure/flyweight/FlyweightFactory.java

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+package structure.flyweight;/**
+ * Created by MirsFang on 2017/3/9.
+ */
+
+import structure.flyweight.flyweightAbs.Flyweight;
+
+import java.util.HashMap;
+
+/***
+ *作者：MirsFang    
+ *模式：享元模式
+ *时间：2017/03/09/下午12:38  
+ *备注  享元工厂
+ ***/
+
+public class FlyweightFactory {
+    //定义一个池容器
+    private static HashMap<String,Flyweight> pool=new HashMap<>();
+
+    public static Flyweight getFlyweight(String Extrinsic){
+        //需要返回的对象
+        Flyweight flyweight=null;
+        if(pool.containsKey(Extrinsic)){
+            flyweight=pool.get(Extrinsic);
+        }else {
+            flyweight=new ConcreateFlyweight_1(Extrinsic);
+            pool.put(Extrinsic,flyweight);
+        }
+        return flyweight;
+    }
+
+
+    //获取池的大小
+    public static  int getPoolSize(){
+        return pool.size();
+    }
+}

src/structure/flyweight/FlyweightMain.java

@@ -0,0 +1,47 @@
+package structure.flyweight;/**
+ * Created by MirsFang on 2017/3/9.
+ */
+
+import structure.flyweight.flyweightAbs.Flyweight;
+
+/***
+ *作者：MirsFang    
+ *模式：享元模式
+ *时间：2017/03/09/下午12:44  
+ *备注  享元模式执行类
+ ***/
+
+public class FlyweightMain {
+
+
+    public static void main(String[] args) {
+        Flyweight fly1;
+        Flyweight fly2;
+        Flyweight fly3;
+        Flyweight fly4;
+        Flyweight fly5;
+        Flyweight fly6;
+
+        //根据类型创建订单对象
+        fly1 = FlyweightFactory.getFlyweight("图书");
+        fly2 = FlyweightFactory.getFlyweight("图书");
+        fly3 = FlyweightFactory.getFlyweight("图书");
+        fly4 = FlyweightFactory.getFlyweight("图书");
+        fly5 = FlyweightFactory.getFlyweight("你懂得");
+        fly6 = FlyweightFactory.getFlyweight("女神娃娃");
+
+        //调用
+        fly1.operate();
+        fly2.operate();
+        fly3.operate();
+        fly4.operate();
+        fly5.operate();
+        fly6.operate();
+
+        //查看池中对象的数量
+        System.out.print("pool 中对象的大小 = "+FlyweightFactory.getPoolSize());
+
+    }
+
+
+}

src/structure/flyweight/flyweight.md

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+# 享元模式（Flyweight Pattern）
+
+享元模式是池技术的实现方式。
+
+> 使共享对象可有效地支持大量细粒度的对象
+
+说白了就是通过共享对象去支持大量的不同对象
+
+我们都知道new一个对象是需要成本的，CPU成本和内存成本，当你需要new出大量的对象的时候（尤其是在服务端，比如说商品抢购，瞬间订单量指数增加），特别容易造成内存溢出导致宕机。
+
+这里需要用两个概念
+
+* 内部状态
+  * 对象可共享出来的信息，存储在对象内部不会随环境改变而改变
+* 外部状态
+  * 外部状态是对象得以依赖的一个标记，是随环境改变而改变，不可共享的状态
+
+
+
+| 类名                   | 描述      |
+| -------------------- | ------- |
+| Flyweight            | 抽象享元对象  |
+| ConcreateFlyweight_1 | 具体享元对象  |
+| FlyweightFactory     | 享元工厂    |
+| FlyweightMain        | 享元模式执行类 |
+
+
+

src/structure/flyweight/flyweightAbs/Flyweight.java

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+package structure.flyweight.flyweightAbs;/**
+ * Created by MirsFang on 2017/3/9.
+ */
+
+/***             
+ *作者：MirsFang    
+ *模式：享元模式
+ *时间：2017/03/09/下午12:32  
+ *备注  抽象享元对象
+ ***/
+
+public abstract class Flyweight {
+    //内部状态
+    private String intrinsic;
+    //外部状态
+    protected final String Extrinsic;
+    //要求享元角色必须接受外部状态
+    public Flyweight(String extrinsic) {
+        Extrinsic = extrinsic;
+    }
+    //定义业务操作
+    public abstract void operate();
+    //内部状态的get和set
+    public String getIntrinsic() {
+        return intrinsic;
+    }
+
+    public void setIntrinsic(String intrinsic) {
+        this.intrinsic = intrinsic;
+    }
+}