001    /**
002     *   GRANITE DATA SERVICES
003     *   Copyright (C) 2006-2013 GRANITE DATA SERVICES S.A.S.
004     *
005     *   This file is part of the Granite Data Services Platform.
006     *
007     *   Granite Data Services is free software; you can redistribute it and/or
008     *   modify it under the terms of the GNU Lesser General Public
009     *   License as published by the Free Software Foundation; either
010     *   version 2.1 of the License, or (at your option) any later version.
011     *
012     *   Granite Data Services is distributed in the hope that it will be useful,
013     *   but WITHOUT ANY WARRANTY; without even the implied warranty of
014     *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
015     *   General Public License for more details.
016     *
017     *   You should have received a copy of the GNU Lesser General Public
018     *   License along with this library; if not, write to the Free Software
019     *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
020     *   USA, or see <http://www.gnu.org/licenses/>.
021     */
022    package org.granite.clustering;
023    
024    import java.io.Serializable;
025    
026    /**
027     * This class holds a <tt>transient</tt> reference to the object given to its
028     * constructor. When this class is serialized, the reference to the object is
029     * lost.
030     * 
031     * @author Franck WOLFF
032     * 
033     * @see org.granite.messaging.webapp.ServletGraniteContext
034     * @see TransientReference
035     */
036    public final class TransientReferenceHolder implements Serializable {
037    
038            private static final long serialVersionUID = 1L;
039            
040            private final transient Object object;
041            
042            public TransientReferenceHolder(Object object) {
043                    this.object = object;
044            }
045    
046            public Object get() {
047                    return object;
048            }
049    
050            @Override
051            public boolean equals(Object obj) {
052                    if (this == obj)
053                            return true;
054                    if (!(obj instanceof TransientReferenceHolder))
055                            return false;
056                    Object reference = ((TransientReferenceHolder)obj).get();
057                    if (reference == object)
058                            return true;
059                    if (object == null)
060                            return false; 
061                    return object.equals(reference);
062            }
063    
064            @Override
065            public int hashCode() {
066                    if (object != null)
067                            return object.hashCode();
068                    return 0;
069            }
070    
071            @Override
072            public String toString() {
073                    return getClass().getName() + ": " + object;
074            }
075    }