finalarguments.java

来自「thinking in Java书中 的源代码」· Java 代码 · 共 26 行

//: c06:FinalArguments.java
// From 'Thinking in Java, 2nd ed.' by Bruce Eckel
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
// Using "final" with method arguments.

class Gizmo {
  public void spin() {}
}

public class FinalArguments {
  void with(final Gizmo g) {
    //! g = new Gizmo(); // Illegal -- g is final
  }
  void without(Gizmo g) {
    g = new Gizmo(); // OK -- g not final
    g.spin();
  }
  // void f(final int i) { i++; } // Can't change
  // You can only read from a final primitive:
  int g(final int i) { return i + 1; }
  public static void main(String[] args) {
    FinalArguments bf = new FinalArguments();
    bf.without(null);
    bf.with(null);
  }
} ///:~