Note.java 一个枚举类

package Lesson8Polymorphism.music;

public enum Note
{
	MIDDLE_C, C_SHARP, B_FLAT;
}

music5.java

/**
* 书本:《Thinking In Java》
* 功能:接口
* 文件:Music.java
* 时间:2015年4月2日16:50:48
* 作者:cutter_point
*/
package Lesson9Interfaces.music5;

import java.util.Scanner;

import Lesson8Polymorphism.music.Note;
import static net.mindview.util.Print.*;

interface Instrument
{
	int VALUES = 5; 	//默认是static和final的
	void paly(Note n);	//这里不能对方法进行实现
	void adjust();
}

class Wind implements Instrument	//必须实现接口的所有方法
{

	@Override
	public void paly(Note n)
	{
		print(this + ".play() " + n);
	}

	@Override
	public void adjust()
	{
		print(this + ".adjust()");
	}

	public String toString()
	{
		return "Wind()";
	}

}

class Percussion implements Instrument
{

	@Override
	public void paly(Note n)
	{
		print(this + ".play() " + n);
	}

	@Override
	public void adjust()
	{
		print(this + ".adjust()");
	}

	public String toString()
	{
		return "Percussion()";
	}

}

class Stringed implements Instrument
{
	@Override
	public void paly(Note n)
	{
		print(this + ".play() " + n);
	}

	@Override
	public void adjust()
	{
		print(this + ".adjust()");
	}

	public String toString()
	{
		return "Stringed()";
	}

}

class Brass extends Wind
{
	public String toString()
	{
		return "Brass";
	}
}

class Woodwind extends Wind
{
	public String toString()
	{
		return "Woodwind";
	}
}

public class Music5
{
	static void tune(Instrument i)
	{
		i.paly(Note.MIDDLE_C); 			//MIDDLE_C, C_SHARP, B_FLAT;
	}

	static void tuneAll(Instrument[] e)
	{
		//一个个取出来调用tune函数
		for(Instrument i : e)
		{
			tune(i);
		}
	}

	public static void main(String [] args)
	{
//		Scanner s = new Scanner(System.in);
//		System.out.println(s.next());

		Instrument[] orchestra =
			{
				new Wind(),
				new Percussion(),
				new Stringed(),
				new Brass(),
				new Woodwind()
			};

		tuneAll(orchestra);
	}
}

输出结果：

Wind().play() MIDDLE_C  obj1

Percussion().play() MIDDLE_C  obj1

Stringed().play() MIDDLE_C  obj1

Brass.play() MIDDLE_C  obj1

Woodwind.play() MIDDLE_C  obj1