001 /* 002 Copyright (C) 2001-2004 Laurent Martelli <laurent@aopsys.com> 003 004 This program is free software; you can redistribute it and/or modify 005 it under the terms of the GNU Lesser General Public License as 006 published by the Free Software Foundation; either version 2 of the 007 License, or (at your option) any later version. 008 009 This program is distributed in the hope that it will be useful, 010 but WITHOUT ANY WARRANTY; without even the implied warranty of 011 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 012 GNU Lesser General Public License for more details. 013 014 You should have received a copy of the GNU Lesser General Public License 015 along with this program; if not, write to the Free Software 016 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ 017 018 package org.objectweb.jac.aspects.persistence; 019 020 import org.apache.log4j.Logger; 021 022 023 024 /** 025 * Abstract class that defines an object identifier. It should be 026 * subclassed by <code>Storage</code> implementors. 027 * 028 * <strong>Note that you should also define the <code>hashCode</code> 029 * method.</em> 030 */ 031 public abstract class OID implements java.io.Serializable { 032 033 static final Logger logger = Logger.getLogger("persistence"); 034 035 /** 036 * Test if two OIDs are equal. 037 * @param obj the OID to test 038 * @return true if obj equals this OID 039 */ 040 public abstract boolean equals(Object obj); 041 public abstract int hashCode(); 042 043 public OID(Storage storage) { 044 this.storage = storage; 045 if (storage==null) 046 logger.error("Storage is null",new Exception()); 047 } 048 049 /** The storage that defines the OID */ 050 protected Storage storage; 051 public final Storage getStorage() { 052 return storage; 053 } 054 055 public abstract String localId(); 056 }