/**
 * Thrown when an attempt is made to add an item to a priority queue
 * the key of which has a type different from the keys expected.
 * 
 * @version     1.1   June 30, 2000
 * @author      Franck van Breugel
 */
public class InvalidKeyException extends RuntimeException 
{
    /** 
     * Constructs an InvalidKeyException without error message.
     */
    public InvalidKeyException() 
    {
        super();
    }

    /** 
     * Constructs an InvalidKeyException with the specified error message.
     *
     * @param errorMessage Error message.
     */
    public InvalidKeyException(String errorMessage) 
    {
        super(errorMessage);
    }
}