享元模式
享元模式（Flyweight Pattern）主要用于减少创建对象的数量，以减少内存占用和提高性能。
这种类型的设计模式属于结构型模式，它提供了减少对象数量从而改善应用所需的对象结构的方式。
享元模式尝试重用现有的同类对象，如果未找到匹配的对象，则创建新对象
实际案例
类信息概览：
| 类名 | 说明 |
|---|---|
| Main.java | 方法的总入口 |
| RectangleFactory.java | 工厂 |
| Rectangle.java | 长方形 |
定义
- RectangleFactory.java
package com.ryo.design.pattern.note.flyweight;
import java.util.HashMap;
import java.util.Map;
/**
* @author houbinbin
* @version 1.0
* @on 2017/8/12
* @since 1.7
*/
public class RectangleFactory {
private static Map<String, Rectangle> rectangleMap = new HashMap<>();
public static Rectangle getRectangle(String color) {
Rectangle rectangle = rectangleMap.get(color);
if(rectangle == null) {
rectangle = new Rectangle();
rectangle.setColor(color);
rectangleMap.put(color, rectangle);
}
return rectangle;
}
}
- Rectangle.java
package com.ryo.design.pattern.note.flyweight;
import lombok.Data;
/**
* @author houbinbin
* @version 1.0
* @on 2017/8/12
* @since 1.7
*/
@Data
public class Rectangle {
private int width;
private int weight;
private String color;
}
测试
- Main.java
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
* Copyright (c) 2012-2018. houbinbini Inc.
* design-pattern All rights reserved.
*/
package com.ryo.design.pattern.note.flyweight;
/**
* <p> </p>
*
* <pre> Created: 2018/5/17 下午8:41 </pre>
* <pre> Project: design-pattern </pre>
*
* @author houbinbin
* @version 1.0
* @since JDK 1.7
*/
public class Main {
public static void main(String[] args) {
Rectangle rectangle = RectangleFactory.getRectangle("RED");
rectangle.setWeight(11);
Rectangle rectangle2 = RectangleFactory.getRectangle("BLUE");
rectangle2.setWeight(12);
Rectangle rectangle3 = RectangleFactory.getRectangle("YELLOW");
rectangle3.setWeight(13);
Rectangle rectangle4 = RectangleFactory.getRectangle("RED");
rectangle4.setWeight(14);
Rectangle rectangle5 = RectangleFactory.getRectangle("BLUE");
rectangle5.setWeight(15);
System.out.println(rectangle);
System.out.println(rectangle2);
System.out.println(rectangle3);
System.out.println(rectangle4);
System.out.println(rectangle5);
}
}
- 测试结果
Rectangle(width=0, weight=14, color=RED)
Rectangle(width=0, weight=15, color=BLUE)
Rectangle(width=0, weight=13, color=YELLOW)
Rectangle(width=0, weight=14, color=RED)
Rectangle(width=0, weight=15, color=BLUE)
实现方式
UML & Code
UML
UML 图示如下
Code
代码地址
