java--多态的主板实例

/*
需求：
电脑运行实例
电脑运行基于主板
*/
interface PCI               //接口
{
	public void open();
	public void close();
}

class MainBoard             //主板
{
	public void run()
	{
		System.out.println("mainboard run");
	}
	public void usePCI(PCI p)     
	{
		if(p!=null)
		{
			p.open();
			p.close();
		}
	}
}

class NetCard implements PCI         //实现PCI接口的网卡
{
	public void open()
	{
		System.out.println("netcard open");
	}
	public void close()
	{
		System.out.println("netcard close");
	}
}

class SoundCard implements PCI        ////实现PCI接口的声卡
{
	public void open()
	{
		System.out.println("soundcard open");
	}
	public void close()
	{
		System.out.println("soundcard close");
	}

}


class duotaiDemo2 
{
	public static void main(String[] args) 
	{
		MainBoard mb = new MainBoard();
		mb.run();
		mb.usePCI(new NetCard());
		mb.usePCI(new SoundCard());
		System.out.println("Hello World!");
	}
}