/*
* Copyright (C) 2010 eXo Platform SAS.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.exoplatform.portal.pom.config.cache;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamException;
import java.io.Serializable;
/**
* A serializable object that is a private marker representing a null value.
*
* @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
* @version $Revision$
*/
public class NullObject implements Serializable {
/** VM singleton. */
private static final NullObject instance = new NullObject();
public static NullObject get() {
return instance;
}
private Object readResolve() throws ObjectStreamException {
return instance;
}
private void writeObject(ObjectOutputStream out) throws IOException {
// Nothing to do
}
private void readObject(ObjectInputStream in) throws IOException {
// Nothing to do
}
@Override
public String toString() {
return "NullObject[]";
}
}