speedmeter.java

疯狂Java讲义_源码(含Java设计模式CHM

/**
 * Description:
 * <br/>Copyright (C), 2005-2008, 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 abstract class SpeedMeter
{
	//转速
	private double turnRate;
	public SpeedMeter()
	{
	}
	//把返回车轮半径的方法定义成抽象方法
	public abstract double getRadius();
	public void setTurnRate(double turnRate)
	{
		this.turnRate = turnRate;
	}
	//定义计算速度的通用算法
	public double getSpeed()
	{
		//速度等于 车轮半径 * 2 * PI * 转速
		return java.lang.Math.PI * 2 * getRadius() * turnRate;
	}
}