001    /*
002      GRANITE DATA SERVICES
003      Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.
004    
005      This file is part of Granite Data Services.
006    
007      Granite Data Services is free software; you can redistribute it and/or modify
008      it under the terms of the GNU Library General Public License as published by
009      the Free Software Foundation; either version 2 of the License, or (at your
010      option) any later version.
011    
012      Granite Data Services is distributed in the hope that it will be useful, but
013      WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
014      FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
015      for more details.
016    
017      You should have received a copy of the GNU Library General Public License
018      along with this library; if not, see <http://www.gnu.org/licenses/>.
019    */
020    
021    package org.granite.clustering;
022    
023    import java.io.Serializable;
024    
025    /**
026     * This class holds a <tt>transient</tt> reference to the object given to its
027     * constructor. When this class is serialized, the reference to the object is
028     * lost.
029     * 
030     * @author Franck WOLFF
031     * 
032     * @see org.granite.messaging.webapp.HttpGraniteContext
033     * @see TransientReference
034     */
035    public final class TransientReferenceHolder implements Serializable {
036    
037            private static final long serialVersionUID = 1L;
038            
039            private final transient Object object;
040            
041            public TransientReferenceHolder(Object object) {
042                    this.object = object;
043            }
044    
045            public Object get() {
046                    return object;
047            }
048    
049            @Override
050            public boolean equals(Object obj) {
051                    if (this == obj)
052                            return true;
053                    if (!(obj instanceof TransientReferenceHolder))
054                            return false;
055                    Object reference = ((TransientReferenceHolder)obj).get();
056                    if (reference == object)
057                            return true;
058                    if (object == null)
059                            return false; 
060                    return object.equals(reference);
061            }
062    
063            @Override
064            public int hashCode() {
065                    if (object != null)
066                            return object.hashCode();
067                    return 0;
068            }
069    
070            @Override
071            public String toString() {
072                    return getClass().getName() + ": " + object;
073            }
074    }