001/*
002 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 * 
016 * Contributors:
017 *     Nuxeo - initial API and implementation
018 *
019 * $Id$
020 */
021
022package org.nuxeo.common.utils;
023
024import java.io.Serializable;
025
026/**
027 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a>
028 */
029public final class Null implements Serializable {
030
031    public static final Null VALUE = new Null();
032
033    private static final long serialVersionUID = 1L;
034
035    private Null() {
036    }
037
038    /**
039     * Serialization handling.
040     */
041    private Object readResolve() {
042        return VALUE;
043    }
044
045    @Override
046    public String toString() {
047        return "Null";
048    }
049
050}