| /* java.beans.PersistenceDelegate |
| Copyright (C) 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package java.beans; |
| |
| /** <p>A <code>PersistenceDelegate</code> describes how a another object |
| * has to constructed and transformed in order to create a complete |
| * replicate.</p> |
| * |
| * <p>For custom classes you will need to implement |
| * <code>PersistenceDelegate</code> in a way that is suitable for them. |
| * To make use of the implementation you have to register it with an |
| * {@link Encoder} using the {Encoder#setPersistenceDelegate} method.</p> |
| * |
| * @author Robert Schuster (robertschuster@fsfe.org) |
| * @since 1.4 |
| */ |
| public abstract class PersistenceDelegate |
| { |
| |
| protected void initialize(Class type, Object oldInstance, Object newInstance, |
| Encoder out) |
| { |
| if (type != Object.class) |
| { |
| type = type.getSuperclass(); |
| |
| PersistenceDelegate pd = out.getPersistenceDelegate(type); |
| |
| pd.initialize(type, oldInstance, newInstance, out); |
| } |
| } |
| |
| public void writeObject(Object oldInstance, Encoder out) |
| { |
| Object streamCandidate = out.get(oldInstance); |
| |
| if (mutatesTo(oldInstance, streamCandidate)) |
| { |
| initialize(oldInstance.getClass(), oldInstance, streamCandidate, out); |
| } |
| else |
| { |
| out.remove(oldInstance); |
| out.writeExpression(instantiate(oldInstance, out)); |
| } |
| } |
| |
| protected boolean mutatesTo(Object oldInstance, Object newInstance) |
| { |
| return (newInstance != null) |
| && oldInstance.getClass() == newInstance.getClass(); |
| } |
| |
| protected abstract Expression instantiate(Object oldInstance, Encoder out); |
| } |