一个多态低耦合的设计

class Person
{
	String name;
}


class Father extends Person
{
	//String name;
	void da(Children c)
	{
		c.beiDa();
	}
	
}


abstract class Children extends Person
{
	//String name;
	abstract void beiDa();
}

class Son extends Children
{
	void beiDa()
	{
		pao();
	}
	void pao()
	{
		System.out.println("son pao");
	}
}

class Daughter extends Children
{
	void beiDa()
	{
		cry();
	}
	void cry()
	{
		System.out.println("dau cry");
	}
}

class Family2
{
	public static void main(String[] args)
	{
		Father f = new Father();
		Son s = new Son();
		f.da(s);
		f.da(new Daughter());

		f.da(f);
	}
}