client.java

设计模式描述设计模式描述设计模式描述设计模式描述

/*
 * Created on 2005-5-11
 *
 意图 运用共享技术有效地支持大量细粒度的对象。 
 适用性 一个应用程序使用了大量的对象。 
 完全由于使用大量的对象，造成很大的存储开销。 
 对象的大多数状态都可变为外部状态。 
 如果删除对象的外部状态，那么可以用相对较少的共享对象取代很多组对象。 
 应用程序不依赖于对象标识。由于F l y w e i g h t 对象可以被共享，对于概念上明显有别的对象，标识测试将返回真值。 
 */
package com.test.pattern.struct.flyweight;

import java.util.ArrayList;

/**
 * @author Administrator
 * 
 * TODO To change the template for this generated type comment go to Window -
 * Preferences - Java - Code Style - Code Templates
 */
class FlyweightFactory {
	private ArrayList pool = new ArrayList();

	// the flyweightfactory can crete all entries in the pool at startup
	// (if the pool is small, and it is likely all will be used), or as
	// needed, if the pool si large and it is likely some will never be used
	public FlyweightFactory() {
		pool.add(new ConcreteEvenFlyweight());
		pool.add(new ConcreteUnevenFlyweight());
	}

	public Flyweight GetFlyweight(int key) {
		// here we would determine if the flyweight identified by key
		// exists, and if so return it. If not, we would create it.
		// As in this demo we have implementation all the possible
		// flyweights we wish to use, we retrun the suitable one.
		int i = key % 2;
		return ((Flyweight) pool.get(i));
	}
}

abstract class Flyweight {
	abstract public void DoOperation(int extrinsicState);
}

class UnsharedConcreteFlyweight extends Flyweight {
	public void DoOperation(int extrinsicState) {

	}
}

class ConcreteEvenFlyweight extends Flyweight {
	public void DoOperation(int extrinsicState) {
		System.out.println("In ConcreteEvenFlyweight.DoOperation: "
				+ extrinsicState);
	}
}

class ConcreteUnevenFlyweight extends Flyweight {
	public void DoOperation(int extrinsicState) {
		System.out.println("In ConcreteUnevenFlyweight.DoOperation: "
				+ extrinsicState);
	}
}

/// <summary>
/// Summary description for Client.
/// </summary>

public class Client {
	public static void main(String[] args) {
		int[] data = { 1, 2, 3, 4, 5, 6, 7, 8 };

		FlyweightFactory f = new FlyweightFactory();

		int extrinsicState = 3;
		for (int i = 0; i < data.length; i++) {
			Flyweight flyweight = f.GetFlyweight(i);
			flyweight.DoOperation(extrinsicState);
		}

	}
}