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1: /* java.beans.PersistenceDelegate 2: Copyright (C) 2005 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: package java.beans; 39: 40: /** <p>A <code>PersistenceDelegate</code> describes how a another object 41: * has to constructed and transformed in order to create a complete 42: * replicate.</p> 43: * 44: * <p>For custom classes you will need to implement 45: * <code>PersistenceDelegate</code> in a way that is suitable for them. 46: * To make use of the implementation you have to register it with an 47: * {@link Encoder} using the {Encoder#setPersistenceDelegate} method.</p> 48: * 49: * @author Robert Schuster (robertschuster@fsfe.org) 50: * @since 1.4 51: */ 52: public abstract class PersistenceDelegate 53: { 54: 55: protected void initialize(Class type, Object oldInstance, Object newInstance, 56: Encoder out) 57: { 58: if (type != Object.class) 59: { 60: type = type.getSuperclass(); 61: 62: PersistenceDelegate pd = out.getPersistenceDelegate( 63: oldInstance.getClass().getSuperclass()); 64: 65: pd.initialize(type, oldInstance, newInstance, out); 66: } 67: } 68: 69: public void writeObject(Object oldInstance, Encoder out) 70: { 71: Object streamCandidate = out.get(oldInstance); 72: 73: if (mutatesTo(oldInstance, streamCandidate)) 74: { 75: initialize(oldInstance.getClass(), oldInstance, streamCandidate, out); 76: } 77: else 78: { 79: out.remove(oldInstance); 80: out.writeExpression(instantiate(oldInstance, out)); 81: } 82: } 83: 84: protected boolean mutatesTo(Object oldInstance, Object newInstance) 85: { 86: return (newInstance != null) 87: && oldInstance.getClass() == newInstance.getClass(); 88: } 89: 90: protected abstract Expression instantiate(Object oldInstance, Encoder out); 91: }
GNU Classpath (0.20) |