Demonstrates the use of instance comparisons : Class « Reflection « Java Tutorial

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/*
 *     file: InstanceOfDemo.java
 *  package: oreilly.hcj.reflection
 *
 * This software is granted under the terms of the Common Public License,
 * CPL, which may be found at the following URL:
 * http://www-124.ibm.com/developerworks/oss/CPLv1.0.htm
 *
 * Copyright(c) 2003-2005 by the authors indicated in the @author tags.
 * All Rights are Reserved by the various authors.
 *
 ########## DO NOT EDIT ABOVE THIS LINE ########## */

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import javax.swing.JPanel;

/**
 * Demonstrates the use of instance comparisons.
 * 
 * @author <a href=mailto:kraythe@arcor.de>Robert Simmons jr. (kraythe)</a>
 * @version $Revision: 1.3 $
 */
public class InstanceOfDemo {
  /** A set of demon objects. */
  public static final Set OBJECT_SET;

  static {
    Set objectSet = new HashSet();
    objectSet.add(new Integer(5));
    objectSet.add(new String("Hardcore Java"));
    objectSet.add(new Float(22.5f));
    objectSet.add(new JPanel());
    objectSet.add(new Character('x'));
    objectSet.add(new ArrayList());
    objectSet.add(new Double(354.5676));
    objectSet.add(null);
    OBJECT_SET = Collections.unmodifiableSet(objectSet);
  }

  /**
   * Demo method.
   * 
   * @param args
   *          Command Line arguments.
   */
  public static void main(final String[] args) {
    final Iterator iter = OBJECT_SET.iterator();
    Object obj = null;

    while (iter.hasNext()) {
      obj = iter.next();
      if (obj instanceof Number) {
        System.out.println(obj);
      }
    }
  }
}

/* ########## End of File ########## */