/* ======================================================================
The Bodington System Software License, Version 1.0
  
Copyright (c) 2001 The University of Leeds.  All rights reserved.
  
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

1.  Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.

2.  Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

3.  The end-user documentation included with the redistribution, if any,
must include the following acknowledgement:  "This product includes
software developed by the University of Leeds
(http://www.bodington.org/)."  Alternately, this acknowledgement may
appear in the software itself, if and wherever such third-party
acknowledgements normally appear.

4.  The names "Bodington", "Nathan Bodington", "Bodington System",
"Bodington Open Source Project", and "The University of Leeds" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
d.gardner@leeds.ac.uk.

5.  The name "Bodington" may not appear in the name of products derived
from this software without prior written permission of the University of
Leeds.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO,  TITLE,  THE IMPLIED WARRANTIES 
OF QUALITY  AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO 
EVENT SHALL THE UNIVERSITY OF LEEDS OR ITS CONTRIBUTORS BE LIABLE FOR 
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
POSSIBILITY OF SUCH DAMAGE.
=========================================================

This software was originally created by the University of Leeds and may contain voluntary 
contributions from others.  For more information on the Bodington Open Source Project, please 
see http://bodington.org/

====================================================================== */

package org.bodington.database;

/**
 * A class similar to Integer used to represent a primary key for a java object.
 * 
 * @author Jon Maber
 * @version 1
 */

public class PrimaryKey extends java.lang.Number
	{

	/**
	 * The actual int value that will be used for storage of this key.
	 * The storage system will have to use a 4 byte integer for the
	 * key.
	 */
	private int myint;

	/**
	 * PrimaryKey can be constructed with an int.
	 * 
	 * @param i The number used to represent this key in storage.
	 */
	
	public PrimaryKey( int i )
		{
		myint=i;
		}

	/**
	 * Outputs the int value as a string.
	 * @return A string created with Integer.toString()
	 */
	
	public String toString()
		{
		return Integer.toString( myint );
		}

	/**
	 * Retrieves the int value.
	 * @return The underlying int value.
	 */
		
	public int intValue()
		{
		return myint;
		}

	/**
	 * Retrieves the int value cast to a long.
	 * @return The int padded out to a long.
	 */
		
	public long longValue()
		{
		return myint;
		}

	/**
	 * Retrieves the int value cast to a double.
	 * @return A double.
	 */
	
	public double doubleValue()
		{
		return myint;
		}

	/**
	 * Retrieves the int value cast to a float.
	 * @return A float value.
	 */
	
	public float floatValue()
		{
		return myint;
		}

    /**
     * Returns a hashcode for this PrimaryKey.
     *
     * @return  A hash code value for this object. (Actually the int value.)
     */
    public int hashCode()
    	{
		return myint;
    	}

    /**
     * Compares this object to the specified object.
     * If this method wasn't included the PrimaryKeys
     * would be compared by reference instead and two
     * instances of the same PrimaryKey would be
     * considered unequal.  This is important for storing
     * PersistentOjbects in Hashtables etc.
     *
     * @param   obj   the object to compare with.
     * @return  <code>true</code> if the objects are the same;
     *          <code>false</code> otherwise.
     */
    public boolean equals(Object obj)
    	{
		if ((obj != null) && (obj instanceof PrimaryKey))
			{
	    	return myint == ((PrimaryKey)obj).intValue();
			}
		return false;
    	}
	}