95 lines
2.0 KiB
Java
95 lines
2.0 KiB
Java
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//: interfaces/music4/Music4.java
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// <20>2015 MindView LLC: see Copyright.txt
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// Abstract classes and methods.
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package interfaces.music4;
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import polymorphism.music.Note;
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import static com.mindviewinc.util.Print.*;
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abstract class Instrument {
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private int i; // Storage allocated for each
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public abstract void play(Note n);
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public String what() { return "Instrument"; }
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public abstract void adjust();
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}
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class Wind extends Instrument {
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@Override
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public void play(Note n) {
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print("Wind.play() " + n);
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}
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@Override
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public String what() { return "Wind"; }
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@Override
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public void adjust() {}
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}
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class Percussion extends Instrument {
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@Override
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public void play(Note n) {
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print("Percussion.play() " + n);
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}
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@Override
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public String what() { return "Percussion"; }
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@Override
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public void adjust() {}
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}
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class Stringed extends Instrument {
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@Override
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public void play(Note n) {
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print("Stringed.play() " + n);
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}
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@Override
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public String what() { return "Stringed"; }
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@Override
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public void adjust() {}
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}
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class Brass extends Wind {
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@Override
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public void play(Note n) {
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print("Brass.play() " + n);
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}
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@Override
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public void adjust() { print("Brass.adjust()"); }
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}
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class Woodwind extends Wind {
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@Override
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public void play(Note n) {
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print("Woodwind.play() " + n);
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}
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@Override
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public String what() { return "Woodwind"; }
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}
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public class Music4 {
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// Doesn't care about type, so new types
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// added to the system still work right:
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static void tune(Instrument i) {
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// ...
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i.play(Note.MIDDLE_C);
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}
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static void tuneAll(Instrument[] e) {
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for(Instrument i : e)
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tune(i);
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}
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public static void main(String[] args) {
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// Upcasting during addition to the array:
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Instrument[] orchestra = {
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new Wind(),
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new Percussion(),
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new Stringed(),
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new Brass(),
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new Woodwind()
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};
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tuneAll(orchestra);
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}
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} /* Output:
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Wind.play() MIDDLE_C
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Percussion.play() MIDDLE_C
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Stringed.play() MIDDLE_C
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Brass.play() MIDDLE_C
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Woodwind.play() MIDDLE_C
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*///:~
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