/*
  * JBoss, Home of Professional Open Source
  * Copyright 2005, JBoss Inc., and individual contributors as indicated
  * by the @authors tag. See the copyright.txt in the distribution for a
  * full listing of individual contributors.
  *
  * This is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as
  * published by the Free Software Foundation; either version 2.1 of
  * the License, or (at your option) any later version.
  *
  * This software is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this software; if not, write to the Free
  * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
  */
package org.jboss.messaging.util;

/**
 * A SimpleIDGenerator
 * 
 * @author <a href="mailto:tim.fox@jboss.com">Tim Fox</a>
 *
 */
public class SimpleIDGenerator implements IDGenerator
{
   private long idSequence;

   private boolean wrapped;

   public SimpleIDGenerator(final long startID)
   {
      idSequence = startID;
   }

   public synchronized long generateID()
   {
      long id = idSequence++;

      if (idSequence == Long.MIN_VALUE)
      {
         wrapped = true;
      }

      if (wrapped)
      {
         // Wrap - Very unlikely to happen
         throw new IllegalStateException("Exhausted ids to use!");
      }

      return id;
   }

   public synchronized long getCurrentID()
   {
      return idSequence;
   }
}