//: c07:RTTI.java
// From Thinking in Java, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// Downcasting & Run-Time Type
// Identification (RTTI)
import java.util.*;

class Useful {
  public void f() {}
  public void g() {}
}

class MoreUseful extends Useful {
  public void f() {}
  public void g() {}
  public void u() {}
  public void v() {}
  public void w() {}
}

public class RTTI {
  public static void main(String[] args) {
    Useful[] x = {
      new Useful(),
      new MoreUseful()
    };
    x[0].f();
    x[1].g();
    // Compile-time: method not found in Useful:
    //! x[1].u();
    ((MoreUseful)x[1]).u(); // Downcast/RTTI
    ((MoreUseful)x[0]).u(); // Exception thrown
  }
} ///:~