二十三种设计模式之蝇量模式(享元模式)

来源：互联网发布：新疆大学教务网络系统编辑：程序博客网时间：2024/04/30 15:58

蝇量模式(享元模式):通过共享方式高效支持大量细粒度对象. 将一个对象抽象出内部属性作为蝇量对象抽象出外部属性作为管理外部状态

特点:减少运行时对象实例的个数,节省开销和内存

public class Tree {    private int xCoord,yCoord,age;    public Tree(int xCoord, int yCoord, int age) {        this.xCoord = xCoord;        this.yCoord = yCoord;        this.age = age;    }    public void display(){    }}

public class TreeTest {    private int length=10000000;    private Tree[] treelst = new Tree[length];    public TreeTest() {        for (int i=0 ;i<length;i++){            treelst[i] = new Tree((int)(Math.random()*length),                        (int)(Math.random()*length),(int)(Math.random()*length)%5);        }    }    public void display(){        for(int i=0;i<treelst.length;i++){            treelst[i].display();        }    }}

public class MainTest {    public static void main(String[] args) {//        showInfo();//        TreeTest treeTest;//        treeTest = new TreeTest();////        showInfo();//        treeTest.display();//        showInfo();//        showInfo();////        TreeManager treeManager;//        treeManager = new TreeManager();////        showInfo();//        treeManager.displayTrees();//        showInfo();        showInfo();        PlantManager plantManager;        plantManager = new PlantManager();        showInfo();        plantManager.display();        showInfo();    }    public static void showInfo(){        //最大内存        long max = Runtime.getRuntime().maxMemory();        //分配内存        long total = Runtime.getRuntime().totalMemory();        //空闲内存        long freeMemory = Runtime.getRuntime().freeMemory();        //已使用内存        long used = total -freeMemory;        System.out.println("max="+max);        System.out.println("total="+total);        System.out.println("freeMemory="+freeMemory);        System.out.println("used="+used);        System.out.println("时间="+System.currentTimeMillis());        System.out.println("=========================================");    }}

public class TreeFlyWeight {    public TreeFlyWeight() {    }    public void display(int xCoord,int yCoord,int age){//        System.out.println('x');    }}

public class TreeManager {    private int length = 10000000;    int[] xArray = new int[length],yArray = new int[length],AgeArray = new int[length];    private TreeFlyWeight treeFlyWeight;    public TreeManager() {        treeFlyWeight = new TreeFlyWeight();        for(int i=0;i<length;i++){            xArray[i] = (int)(Math.random()*length);            yArray[i] = (int)(Math.random()*length);            AgeArray[i] = (int)(Math.random()*length)%5;        }    }    public void displayTrees(){        for (int i=0;i<length;i++){            treeFlyWeight.display(xArray[i],yArray[i],AgeArray[i]);        }    }}

public abstract class Plant {    public Plant(){}    public abstract void display(int xCoord,int yCoord,int age);}

public class Tree2 extends Plant {    @Override    public void display(int xCoord, int yCoord, int age) {        //        System.out.println("Tree2 x");    }}

public class Grass extends Plant {    @Override    public void display(int xCoord, int yCoord, int age) {//        System.out.println("Grass x");    }}

public class PlantFactory {    private HashMap<Integer,Plant> plantHashMap = new HashMap<Integer,Plant>();    public PlantFactory() {    }    public Plant getPlant(int type){        if(!plantHashMap.containsKey(type)){            switch (type){                case 0:                    plantHashMap.put(0,new Tree2());                    break;                case 1:                    plantHashMap.put(1,new Grass());                    break;            }        }        return plantHashMap.get(type);    }}

public class PlantManager {    private int length = 10000000;    private int[] xArray = new int[length],yArray = new int[length],    AgeArray = new int[length],typeArray = new int[length];    private PlantFactory plantFactory;    public PlantManager(){        plantFactory = new PlantFactory();        for(int i=0;i<length;i++){            xArray[i] = (int)(Math.random()*length);            yArray[i] = (int)(Math.random()*length);            AgeArray[i] = (int)(Math.random()*length)%5;            typeArray[i] =  (int)(Math.random()*length)%2;        }    }    public void display(){        for(int i=0;i<length;i++){            plantFactory.getPlant(typeArray[i]).display(xArray[i],yArray[i],AgeArray[i]);        }    }}

*******************************传统方式实现**************************************max=859832320total=58720256freeMemory=56509424used=2210832时间=1502804524796=========================================max=859832320total=350224384freeMemory=69184288used=281 040 096时间=1502804532526=========================================max=859832320total=350224384freeMemory=69184288used=281040096时间=1502804532542=========================================*******************************蝇量实现**************************************max=859832320total=58720256freeMemory=56509424used=2210832时间=1502805198436=========================================max=859832320total=139460608freeMemory=17249728used=12 2210 880时间=1502805199977=========================================max=859832320total=139460608freeMemory=17249728used=12 2210 880时间=1502805199992=========================================*******************************增加草**************************************max=859832320total=58720256freeMemory=56509424used=2210832时间=1502806741592=========================================max=859832320total=179830784freeMemory=17619888used=16 2210 896时间=1502806743749=========================================max=859832320total=179830784freeMemory=17619888used=162210896时间=1502806744340=========================================

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