java 23 种设计模式-12-java 享元模式(Flyweight Pattern)

目录

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：

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

享元模式

系列导航

系列导航