music.java

来自「《Java编程思想》第四版源代码」· Java 代码 · 共 17 行

//: polymorphism/music/Music.java
// Inheritance & upcasting.
package polymorphism.music;

public class Music {
  public static void tune(Instrument i) {
    // ...
    i.play(Note.MIDDLE_C);
  }
  public static void main(String[] args) {
    Wind flute = new Wind();
    tune(flute); // Upcasting
  }
} /* Output:
Wind.play() MIDDLE_C
*///:~