//: interfaces/music4/Music4.java
// Abstract classes and methods.
package object;
import static net.mindview.util.Print.print;enum Note {MIDDLE_C,MIDDLE_E,MIDDLE_F,
}
abstract class Instrument {private int i; // Storage allocated for eachpublic abstract void play(Note n);public String what() { return "Instrument"; }public abstract void adjust();
}class Wind extends Instrument {public void play(Note n) {print("Wind.play() " + n);}public String what() { return "Wind"; }public void adjust() {}
}class Percussion extends Instrument {public void play(Note n) {print("Percussion.play() " + n);}public String what() { return "Percussion"; }public void adjust() {}
}class Stringed extends Instrument {public void play(Note n) {print("Stringed.play() " + n);}public String what() { return "Stringed"; }public void adjust() {}
}    class Brass extends Wind {public void play(Note n) {print("Brass.play() " + n);}public void adjust() { print("Brass.adjust()"); }
}class Woodwind extends Wind {public void play(Note n) {print("Woodwind.play() " + n);}public String what() { return "Woodwind"; }
}    public class Music4 {// Doesn't care about type, so new types// added to the system still work right:static void tune(Instrument i) {// ...
    i.play(Note.MIDDLE_C);}static void tuneAll(Instrument[] e) {for(Instrument i : e)tune(i);}    public static void main(String[] args) {// Upcasting during addition to the array:Instrument[] orchestra = {new Wind(),new Percussion(),new Stringed(),new Brass(),new Woodwind()};tuneAll(orchestra);}
} /* Output:
Wind.play() MIDDLE_C
Percussion.play() MIDDLE_C
Stringed.play() MIDDLE_C
Brass.play() MIDDLE_C
Woodwind.play() MIDDLE_C
*///:~