wind.java

来自「think in java TIJ-3rd-edition-code.zip」· Java 代码 · 共 25 行

//: c06:Wind.java
// Inheritance & upcasting.
import com.bruceeckel.simpletest.*;
import java.util.*;

class Instrument {
  public void play() {}
  static void tune(Instrument i) {
    // ...
    i.play();
  }
}

// Wind objects are instruments
// because they have the same interface:
public class Wind extends Instrument {
  public static void main(String[] args) {
    SimpleTest monitor =
      new SimpleTest("Wind");
    Wind flute = new Wind();
    Instrument.tune(flute); // Upcasting
    monitor.expect(new String[] {
    });
  }
} ///:~