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//: interfaces/music5/Music5.java

// Interfaces.

package interfaces.music5;

import polymorphism.music.Note;

import static net.mindview.util.Print.*;

interface Instrument {

// Compile-time constant:

int VALUE = 5; // static & final

// Cannot have method definitions:

void play(Note n); // Automatically public

void adjust();

}

class Wind implements Instrument {

public void play(Note n) {

print(this + ".play() " + n);

}

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

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

}

class Percussion implements Instrument {

public void play(Note n) {

print(this + ".play() " + n);

}

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

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

}

class Stringed implements Instrument {

public void play(Note n) {

print(this + ".play() " + n);

}

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

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

}

class Brass extends Wind {

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

}

class Woodwind extends Wind {

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

}

public class Music5 {

// 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

*///:~