FileDocCategorySizeDatePackage
Music3.javaAPI DocExample4171Mon Apr 06 18:10:24 BST 1998None

Music3.java

//: Music3.java
//////////////////////////////////////////////////
// Copyright (c) Bruce Eckel, 1998
// Source code file from the book "Thinking in Java"
// All rights reserved EXCEPT as allowed by the
// following statements: You can freely use this file
// for your own work (personal or commercial),
// including modifications and distribution in
// executable form only. Permission is granted to use
// this file in classroom situations, including its
// use in presentation materials, as long as the book
// "Thinking in Java" is cited as the source. 
// Except in classroom situations, you cannot copy
// and distribute this code; instead, the sole
// distribution point is http://www.BruceEckel.com 
// (and official mirror sites) where it is
// freely available. You cannot remove this
// copyright and notice. You cannot distribute
// modified versions of the source code in this
// package. You cannot use this file in printed
// media without the express permission of the
// author. Bruce Eckel makes no representation about
// the suitability of this software for any purpose.
// It is provided "as is" without express or implied
// warranty of any kind, including any implied
// warranty of merchantability, fitness for a
// particular purpose or non-infringement. The entire
// risk as to the quality and performance of the
// software is with you. Bruce Eckel and the
// publisher shall not be liable for any damages
// suffered by you or any third party as a result of
// using or distributing software. In no event will
// Bruce Eckel or the publisher be liable for any
// lost revenue, profit, or data, or for direct,
// indirect, special, consequential, incidental, or
// punitive damages, however caused and regardless of
// the theory of liability, arising out of the use of
// or inability to use software, even if Bruce Eckel
// and the publisher have been advised of the
// possibility of such damages. Should the software
// prove defective, you assume the cost of all
// necessary servicing, repair, or correction. If you
// think you've found an error, please email all
// modified files with clearly commented changes to:
// Bruce@EckelObjects.com. (Please use the same
// address for non-code errors found in the book.)
/////////////////////////////////////////////////

// An extensible program
import java.util.*;

class Instrument3 {
  public void play() {
    System.out.println("Instrument3.play()");
  }
  public String what() {
    return "Instrument3";
  }
  public void adjust() {}
}

class Wind3 extends Instrument3 {
  public void play() {
    System.out.println("Wind3.play()");
  }
  public String what() { return "Wind3"; }
  public void adjust() {}
}

class Percussion3 extends Instrument3 {
  public void play() {
    System.out.println("Percussion3.play()");
  }
  public String what() { return "Percussion3"; }
  public void adjust() {}
}

class Stringed3 extends Instrument3 {
  public void play() {
    System.out.println("Stringed3.play()");
  }
  public String what() { return "Stringed3"; }
  public void adjust() {}
}

class Brass3 extends Wind3 {
  public void play() {
    System.out.println("Brass3.play()");
  }
  public void adjust() {
    System.out.println("Brass3.adjust()");
  }
}

class Woodwind3 extends Wind3 {
  public void play() {
    System.out.println("Woodwind3.play()");
  }
  public String what() { return "Woodwind3"; }
}

public class Music3 {
  // Doesn't care about type, so new types
  // added to the system still work right:
  static void tune(Instrument3 i) {
    // ...
    i.play();
  }
  static void tuneAll(Instrument3[] e) {
    for(int i = 0; i < e.length; i++)
      tune(e[i]);
  }
  public static void main(String[] args) {
    Instrument3[] orchestra = new Instrument3[5];
    int i = 0;
    // Upcasting during addition to the array:
    orchestra[i++] = new Wind3();
    orchestra[i++] = new Percussion3();
    orchestra[i++] = new Stringed3();
    orchestra[i++] = new Brass3();
    orchestra[i++] = new Woodwind3();
    tuneAll(orchestra);
  }
} ///:~