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

  * Cewolf : Chart enabling Web Objects Framework

  * ================================================================

  *

  * Project Info:  http://cewolf.sourceforge.net

  * Project Lead:  Guido Laures (guido@laures.de);

  *

  * (C) Copyright 2002, by Guido Laures

  *

  * This library 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 library 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

  * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,

  * Boston, MA 02111-1307, USA.

  */

 package de.laures.cewolf.taglib.util;

 import java.io.IOException;

 import java.io.Serializable;

 import java.rmi.MarshalledObject;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 /**

  * @author  Guido Laures

  */

 public abstract class KeyGenerator {

     private static final Log log = LogFactory.getLog(KeyGenerator.class);

     private static class NoKeyException extends RuntimeException {

         public NoKeyException(String msg){

             super(msg);

         }

     }

     public static int generateKey(Serializable obj) {

         if (obj == null) {

             NoKeyException ex = new NoKeyException("assertion failed: can not generate key for null,");

             throw ex;

         }

         try {

             MarshalledObject mo = new MarshalledObject(obj);

             return mo.hashCode();

         } catch (IOException ioex) {

             log.error("IOException during key generation KeyGenerator.generateKey()", ioex);

             throw new NoKeyException(obj + " is not serializable.");

         }

     }

 }