testabstract.java

关于隐藏域抽象域的例子

public class TestAbstract
{
	public static void main(String args[])
	{
		PhoneCard200 my200=new PhoneCard200(50.0);
		IC_Card myIC=new IC_Card(50.0);
		System.out.println("200卡可以拨打"+my200.TimeLeft()+"次电话。");
		System.out.println("IC卡可以拨打"+myIC.TimeLeft()+"次电话。");
	}
}
abstract class PhoneCard
{
	double balance;
	abstract void performDial();
	double TimeLeft()
	{
		double current=balance;
		int times=0;
		do
		{
			performDial();
			times++;
		}while(balance>=0);
		balance=current;
		return times-1;
	}
}
class PhoneCard200 extends PhoneCard
{
	static long nextCardNumber;
	static final String connectNumber="200";
	static double additoryFee;
	long cardNumber;
	int password;
	boolean connected;
	
	static
	{
		nextCardNumber=2001800001;
		additoryFee=0.1;
	}
	PhoneCard200(double ib)
	{
		cardNumber=nextCardNumber++;
		balance=ib;
	}
	void performDial()
	{
		balance-=0.5+additoryFee;
	}
}
class IC_Card extends PhoneCard
{
	IC_Card(double ib)
	{
		balance=ib;
	}
	void performDial()
	{
		balance-=0.9;
	}
}