// Copyright(c) 1996,1997 ObjectSpace, Inc.

import java.util.Enumeration;
import COM.objectspace.jgl.*;

/**
 * Construction, enumeration, pushing, popping.
 *
 * @see COM.objectspace.jgl.PriorityQueue
 * @version 2.0.2
 * @author ObjectSpace, Inc.
 */

public class PriorityQueue1
  {
  public static void main( String[] args )
    {
    // Use a HashComparator for comparing elements. Since the hash value of an
    // Integer is its int value, this will order Integers in descending order.
    PriorityQueue queue = new PriorityQueue();
    queue.push( new Integer( 5 ) );
    queue.push( new Integer( -2 ) );
    queue.push( new Integer( 10 ) );
    queue.push( new Integer( 6 ) );
    queue.push( new Integer( 20 ) );
    queue.push( new Integer( -10 ) );

    // Note that although a PriorityQueue always pops objects in the order determined
    // by the comparator, this *does not* mean that the objects are stored in order
    // within the internal data structure. The internal data structure is organized as
    // a heap.
    System.out.println( "Print the PriorityQueue." );
    System.out.println( queue );
    System.out.println();

    System.out.println( "Non-destructively enumerate the PriorityQueue." );
    Enumeration e = queue.elements();
    while ( e.hasMoreElements() )
      System.out.println( e.nextElement() );
    System.out.println();

    System.out.println( "Pop and print each element." );
    while ( !queue.isEmpty() )
      System.out.println( queue.pop() );
    }
  }