franta-hg@1: /* ================================================================
franta-hg@1:  * Cewolf : Chart enabling Web Objects Framework
franta-hg@1:  * ================================================================
franta-hg@1:  *
franta-hg@1:  * Project Info:  http://cewolf.sourceforge.net
franta-hg@1:  * Project Lead:  Guido Laures (guido@laures.de);
franta-hg@1:  *
franta-hg@1:  * (C) Copyright 2002, by Guido Laures
franta-hg@1:  *
franta-hg@1:  * This library is free software; you can redistribute it and/or modify it under the terms
franta-hg@1:  * of the GNU Lesser General Public License as published by the Free Software Foundation;
franta-hg@1:  * either version 2.1 of the License, or (at your option) any later version.
franta-hg@1:  *
franta-hg@1:  * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
franta-hg@1:  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
franta-hg@1:  * See the GNU Lesser General Public License for more details.
franta-hg@1:  *
franta-hg@1:  * You should have received a copy of the GNU Lesser General Public License along with this
franta-hg@1:  * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
franta-hg@1:  * Boston, MA 02111-1307, USA.
franta-hg@1:  */
franta-hg@1: 
franta-hg@1: package de.laures.cewolf.taglib.util;
franta-hg@1: 
franta-hg@1: import java.io.IOException;
franta-hg@1: import java.io.Serializable;
franta-hg@1: import java.rmi.MarshalledObject;
franta-hg@1: 
franta-hg@1: import org.apache.commons.logging.Log;
franta-hg@1: import org.apache.commons.logging.LogFactory;
franta-hg@1: 
franta-hg@1: /**
franta-hg@1:  * @author  Guido Laures
franta-hg@1:  */
franta-hg@1: public abstract class KeyGenerator {
franta-hg@1:     
franta-hg@1:     private static final Log log = LogFactory.getLog(KeyGenerator.class);
franta-hg@1: 
franta-hg@1:     private static class NoKeyException extends RuntimeException {
franta-hg@1:         public NoKeyException(String msg){
franta-hg@1:             super(msg);
franta-hg@1:         }
franta-hg@1:     }
franta-hg@1: 
franta-hg@1:     public static int generateKey(Serializable obj) {
franta-hg@1:         if (obj == null) {
franta-hg@1:             NoKeyException ex = new NoKeyException("assertion failed: can not generate key for null,");
franta-hg@1:             throw ex;
franta-hg@1:         }
franta-hg@1:         try {
franta-hg@1:             MarshalledObject mo = new MarshalledObject(obj);
franta-hg@1:             return mo.hashCode();
franta-hg@1:         } catch (IOException ioex) {
franta-hg@1:             log.error("IOException during key generation KeyGenerator.generateKey()", ioex);
franta-hg@1:             throw new NoKeyException(obj + " is not serializable.");
franta-hg@1:         }
franta-hg@1:     }
franta-hg@1: }