001    /*
002      Copyright (C) 2001 Renaud Pawlak
003    
004      This program is free software; you can redistribute it and/or modify
005      it under the terms of the GNU Lesser General Public License as
006      published by the Free Software Foundation; either version 2 of the
007      License, or (at your option) any later version.
008    
009      This program is distributed in the hope that it will be useful,
010      but WITHOUT ANY WARRANTY; without even the implied warranty of
011      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
012      GNU Lesser General Public License for more details.
013    
014      You should have received a copy of the GNU Lesser General Public License
015      along with this program; if not, write to the Free Software
016      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
017    
018    package org.objectweb.jac.aspects.transaction;
019    
020    
021    
022    import java.util.Iterator;
023    import java.util.Vector;
024    import org.apache.log4j.Logger;
025    import org.objectweb.jac.core.Wrappee;
026    import org.objectweb.jac.core.rtti.ClassItem;
027    import org.objectweb.jac.core.rtti.ClassRepository;
028    import org.objectweb.jac.core.rtti.CollectionItem;
029    import org.objectweb.jac.core.rtti.FieldItem;
030    import org.objectweb.jac.util.Log;
031    
032    public class Merging {
033    
034        static Logger logger = Logger.getLogger("transaction");
035    
036        public static void merge(Wrappee receptor, 
037                                 Wrappee original, 
038                                 Wrappee modified) throws Exception {
039    
040            logger.debug("merging "+modified+" with "+receptor);
041          
042            Vector peerChangedFields = diffFields(receptor,original);
043          
044            Vector changedFields = diffFields(original,modified);
045    
046            Iterator it = changedFields.iterator();
047            while(it.hasNext()) {
048                FieldItem field = (FieldItem)it.next();
049                if( peerChangedFields.contains( field ) ) {
050                    throw new RuntimeException("concurrent modification during transaction on "
051                                               +field);
052                }
053                if( field instanceof CollectionItem ) {
054                    // merge the collections
055                } else {
056                    // we use the setter so that the other aspects are 
057                    // warned of the change
058                    field.setThroughWriter(receptor,field.get(modified));
059                }
060            }
061        }
062    
063        public static Vector diffFields(Wrappee o1, Wrappee o2) {
064          
065            Vector result = new Vector();
066            ClassItem cli = ClassRepository.get().getClass(o1.getClass());
067            FieldItem[] fields = cli.getPrimitiveFields();
068          
069            // diff the primitive fields
070            for( int i=0; i<fields.length; i++ ) {
071                if(!fields[i].get(o1)
072                   .equals(fields[i].get(o2))) {
073                    logger.debug(fields[i]+" differs after transaction");
074                    result.add(fields[i]);
075                }
076            }
077    
078            CollectionItem[] collections = cli.getCollections();
079    
080            // diff the collections (to be implemeted)
081            /*for( int i=0; i<collections.length; i++ ) {
082              if(!collections[i].getActualCollection(o1)
083              .equals(collections[i].getActualCollection(o2))) {
084              result.add(fields[i]);
085              }
086              }*/
087    
088            return result;
089         
090        }
091    
092    } 
093    
094