//: c07:Music4.java
// From Thinking in Java, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// Abstract classes and methods
import java.util.*;

abstract class Instrument4 {
  int i; // storage allocated for each
  public abstract void play();
  public String what() {
    return "Instrument4";
  }
  public abstract void adjust();
}

class Wind4 extends Instrument4 {
  public void play() {
    System.out.println("Wind4.play()");
  }
  public String what() { return "Wind4"; }
  public void adjust() {}
}

class Percussion4 extends Instrument4 {
  public void play() {
    System.out.println("Percussion4.play()");
  }
  public String what() { return "Percussion4"; }
  public void adjust() {}
}

class Stringed4 extends Instrument4 {
  public void play() {
    System.out.println("Stringed4.play()");
  }
  public String what() { return "Stringed4"; }
  public void adjust() {}
}

class Brass4 extends Wind4 {
  public void play() {
    System.out.println("Brass4.play()");
  }
  public void adjust() { 
    System.out.println("Brass4.adjust()");
  }
}

class Woodwind4 extends Wind4 {
  public void play() {
    System.out.println("Woodwind4.play()");
  }
  public String what() { return "Woodwind4"; }
}

public class Music4 {
  // Doesn't care about type, so new types
  // added to the system still work right:
  static void tune(Instrument4 i) {
    // ...
    i.play();
  }
  static void tuneAll(Instrument4[] e) {
    for(int i = 0; i < e.length; i++)
      tune(e[i]);
  }
  public static void main(String[] args) {
    Instrument4[] orchestra = new Instrument4[5];
    int i = 0;
    // Upcasting during addition to the array:
    orchestra[i++] = new Wind4();
    orchestra[i++] = new Percussion4();
    orchestra[i++] = new Stringed4();
    orchestra[i++] = new Brass4();
    orchestra[i++] = new Woodwind4();
    tuneAll(orchestra);
  }
} ///:~