简单工厂

/**
 * Description:
 * <br/>Copyright (C), 2001-2010, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [e-mail]
 * @version  1.0
 */
public class Computer
{
	private Output out;

	public Computer(Output out)
	{
		this.out = out;
	}
	//定义一个模拟获取字符串输入的方法
	public void keyIn(String msg)
	{
		out.getData(msg);
	}
	//定义一个模拟打印的方法
	public void print()
	{
		out.out();
	}
	public static void main(String[] args) 
	{
		//创建OutputFactory
		OutputFactory of = new OutputFactory();
		//将Output对象传入，创建Computer对象
		Computer c = new Computer(of.getOutput());
		c.keyIn("轻量级J2EE企业应用实战");
		c.keyIn("Struts2权威指南");
		c.print();
	}
}

/**
 * Description:
 * <br/>Copyright (C), 2001-2010, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [e-mail]
 * @version  1.0
 */
public interface Output
{
	//接口里定义的属性只能是常量
	int MAX_CACHE_LINE = 50;
	//接口里定义的只能是public的抽象实例方法
	void out();
	void getData(String msg);
}

/**
 * Description:
 * <br/>Copyright (C), 2001-2010, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [e-mail]
 * @version  1.0
 */
public class OutputFactory
{
	public Output getOutput()
	{
		//下面两行代码用于控制系统到底使用Output的哪个实现类。
		//return new Printer();
		return new BetterPrinter();
	}
}

/**
 * Description:
 * <br/>Copyright (C), 2001-2010, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [e-mail]
 * @version  1.0
 */

//让Printer类实现Output
public class Printer implements Output
{
	private String[] printData = new String[MAX_CACHE_LINE];
	//用以记录当前需打印的作业数
	private int dataNum = 0;
	public void out()
	{
		//只要还有作业，继续打印
		while(dataNum > 0)
		{
			System.out.println("打印机打印：" + printData[0]);
			//把作业队列整体前移一位，并将剩下的作业数减1
			System.arraycopy(printData , 1, printData, 0, --dataNum);
		}
	}
	public void getData(String msg)
	{
		if (dataNum >= MAX_CACHE_LINE)
		{
			System.out.println("输出队列已满，添加失败");
		}
		else
		{
			//把打印数据添加到队列里，已保存数据的数量加1。
			printData[dataNum++] = msg;
		}
	}
}

/**
 * Description:
 * <br/>Copyright (C), 2001-2010, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [e-mail]
 * @version  1.0
 */
public class BetterPrinter implements Output
{
	private String[] printData = new String[MAX_CACHE_LINE * 2];
	//用以记录当前需打印的作业数
	private int dataNum = 0;
	public void out()
	{
		//只要还有作业，继续打印
		while(dataNum > 0)
		{
			System.out.println("高速打印机正在打印：" + printData[0]);
			//把作业队列整体前移一位，并将剩下的作业数减1
			System.arraycopy(printData , 1, printData, 0, --dataNum);
		}
	}
	public void getData(String msg)
	{
		if (dataNum >= MAX_CACHE_LINE * 2)
		{
			System.out.println("输出队列已满，添加失败");
		}
		else
		{
			//把打印数据添加到队列里，已保存数据的数量加1。
			printData[dataNum++] = msg;
		}
	}
}