mirror of git://gcc.gnu.org/git/gcc.git
81 lines
3.5 KiB
Java
81 lines
3.5 KiB
Java
/* ClassPersistenceDelegate.java - A PersistenceDelegate for the Class type.
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Copyright (C) 2005 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package gnu.java.beans.encoder;
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import java.beans.Encoder;
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import java.beans.Expression;
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import java.beans.PersistenceDelegate;
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/** <p>The <code>ClassPersistenceDelegate</code> creates
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* <code>Expression</code> instances which denote class resolutions.</p>
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*
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* <p>The class resolution is always the last step when serializing a tree
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* of objects. Due to the recursive nature of the algorithm we need a way
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* to end the recursion. This is achieved by the implementation of this
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* {@link instantiate} method. Arbitrary classes are described with a call
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* to <code>Class.forName</code>. However for the <code>Class</code> class
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* we call <code>getClass()</code> on a <code>String.class</code> instance.
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* This in turn lead to the resolution of the String class which is always
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* encoded as <code>"".getClass()</code>. Finally the <code>Encoder</code>
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* treats strings in a special way so that the recursion ends here.
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*
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* @author Robert Schuster (robertschuster@fsfe.org)
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*/
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public class ClassPersistenceDelegate extends PersistenceDelegate
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{
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protected Expression instantiate(Object oldInstance, Encoder out)
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{
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Class oldClass = (Class) oldInstance;
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// Due to the special handling of String instances in the Encoder
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// this Expression does not lead to further class resolutions.
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if (oldClass == String.class)
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return new Expression(oldClass, "", "getClass", null);
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// This Expression will lead to the class resolution of String.class.
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if (oldClass == Class.class)
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return new Expression(oldClass, String.class, "getClass", null);
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// This Expression will lead to the class resolution of Class.class.
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return new Expression(oldClass, Class.class, "forName",
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new Object[] { oldClass.getName() });
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}
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}
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