设计模式的艺术 第十四章享元设计模式练习（开发一个多功能文档编辑器，在文本文档中可以插入图片、动画、视频等多媒体资料。为了节省系统资源，相同的图片、动画和视频在同一个文档中只需保存一份，但是可以多次重复出现，而且它们每次出现时位置和大小均可不同）

// 抽象多媒体享元类：抽象享元类public abstract class MultimediaFlyweight {    private String name;    protected String resource;
    public MultimediaFlyweight(String name, String resource) {        this.name = name;        this.resource = resource;    }
    public String getName() {        return name;    }
    public abstract String getResource();
    public void display(PosSize posSize) {        System.out.println("展示" + this.name + "，位置行数：" + posSize.getLineNumber() +                ", 大小：高" + posSize.getHeight() + "，宽" + posSize.getWidth());    }}

// 具体图片享元类：具体享元类public class ImageFlyweight extends MultimediaFlyweight{    public ImageFlyweight(String name, String resource) {        super(name, resource);    }
    @Override    public String getResource() {        return this.resource;    }}

// 具体动画享元类：具体享元类public class AnimationFlyweight extends MultimediaFlyweight{    public AnimationFlyweight(String name, String resource) {        super(name, resource);    }
    @Override    public String getResource() {        return this.resource;    }}

// 具体视频享元类：具体享元类public class VideoFlyweight extends MultimediaFlyweight{    public VideoFlyweight(String name, String resource) {        super(name, resource);    }
    @Override    public String getResource() {        return this.resource;    }}

// 多媒体享元工厂类：具体享元工厂类public class FlyweightFactory {    private Hashtable flyweights = new Hashtable();
    public MultimediaFlyweight getFlyweight(String key) {        if (flyweights.containsKey(key)) {            return (MultimediaFlyweight) flyweights.get(key);        }        return null;    }
    public void addFlyweight(String key, String resource, String type) {        if (!this.flyweights.containsKey(key)) {            MultimediaFlyweight flyweight = null;            if (type == "image") {                flyweight = new ImageFlyweight(key, resource);            }            if (type == "animation") {                flyweight = new AnimationFlyweight(key, resource);            }            if (type == "video") {                flyweight = new VideoFlyweight(key, resource);            }            this.flyweights.put(key, flyweight);        }    }}

// 具体位置大小类：外部状态类public class PosSize {    private Integer lineNumber;    private Integer height;    private Integer width;
    public Integer getLineNumber() {        return lineNumber;    }
    public Integer getHeight() {        return height;    }
    public Integer getWidth() {        return width;    }
    public void setLineNumber(Integer lineNumber) {        this.lineNumber = lineNumber;    }
    public void setHeight(Integer height) {        this.height = height;    }
    public void setWidth(Integer width) {        this.width = width;    }}

public class Client {    public static void main(String[] args) {        MultimediaFlyweight image, animation1, animation2, video;        PosSize posSize;        FlyweightFactory flyweightFactory = new FlyweightFactory();        flyweightFactory.addFlyweight("xiaolonglv.png", "图片内容", "image");        flyweightFactory.addFlyweight("张无忌.gif", "动片内容", "animation");        flyweightFactory.addFlyweight("段誉.rmvb", "视频内容", "video");
        image = flyweightFactory.getFlyweight("xiaolonglv.png");        animation1 = flyweightFactory.getFlyweight("张无忌.gif");        animation2 = flyweightFactory.getFlyweight("张无忌.gif");        video = flyweightFactory.getFlyweight("段誉.rmvb");
        posSize = new PosSize();        posSize.setLineNumber(100);        posSize.setHeight(500);        posSize.setWidth(800);        image.display(posSize);
        posSize.setLineNumber(200);        animation1.display(posSize);
        posSize.setLineNumber(300);        animation2.display(posSize);
        posSize.setLineNumber(400);        video.display(posSize);    }}

展示xiaolonglv.png，位置行数：100, 大小：高500，宽800展示张无忌.gif，位置行数：200, 大小：高500，宽800展示张无忌.gif，位置行数：300, 大小：高500，宽800展示段誉.rmvb，位置行数：400, 大小：高500，宽800