| /* ClassPersistenceDelegate.java - A PersistenceDelegate for the Class type. |
| 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 gnu.java.beans.encoder; |
| |
| import java.beans.Encoder; |
| import java.beans.Expression; |
| import java.beans.PersistenceDelegate; |
| |
| /** <p>The <code>ClassPersistenceDelegate</code> creates |
| * <code>Expression</code> instances which denote class resolutions.</p> |
| * |
| * <p>The class resolution is always the last step when serializing a tree |
| * of objects. Due to the recursive nature of the algorithm we need a way |
| * to end the recursion. This is achieved by the implementation of this |
| * {@link instantiate} method. Arbitrary classes are described with a call |
| * to <code>Class.forName</code>. However for the <code>Class</code> class |
| * we call <code>getClass()</code> on a <code>String.class</code> instance. |
| * This in turn lead to the resolution of the String class which is always |
| * encoded as <code>"".getClass()</code>. Finally the <code>Encoder</code> |
| * treats strings in a special way so that the recursion ends here. |
| * |
| * @author Robert Schuster (robertschuster@fsfe.org) |
| */ |
| public class ClassPersistenceDelegate extends PersistenceDelegate |
| { |
| |
| protected Expression instantiate(Object oldInstance, Encoder out) |
| { |
| Class oldClass = (Class) oldInstance; |
| |
| // Due to the special handling of String instances in the Encoder |
| // this Expression does not lead to further class resolutions. |
| if (oldClass == String.class) |
| return new Expression(oldClass, "", "getClass", null); |
| |
| // This Expression will lead to the class resolution of String.class. |
| if (oldClass == Class.class) |
| return new Expression(oldClass, String.class, "getClass", null); |
| |
| // This Expression will lead to the class resolution of Class.class. |
| return new Expression(oldClass, Class.class, "forName", |
| new Object[] { oldClass.getName() }); |
| } |
| |
| } |