/*
 * JBoss, Home of Professional Open Source
 * Copyright 2005, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * 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.jboss.ejb.plugins.cmp.jdbc;

import org.jboss.ejb.plugins.cmp.jdbc.bridge.JDBCCMRFieldBridge;

/**
 * This class represents one pair of entities in a relation.
 *
 * @author <a href="mailto:dain@daingroup.com">Dain Sundstrom</a>
 * @version $Revision: 1.3.4.2 $
 */
public final class RelationPair {
   private final JDBCCMRFieldBridge leftCMRField;
   private final JDBCCMRFieldBridge rightCMRField;

   private final Object leftId;
   private final Object rightId;
   
   public RelationPair(
         JDBCCMRFieldBridge leftCMRField, Object leftId, 
         JDBCCMRFieldBridge rightCMRField, Object rightId) {

      this.leftCMRField = leftCMRField;
      this.leftId = leftId;
      
      this.rightCMRField = rightCMRField;
      this.rightId = rightId;
   }

   public Object getLeftId() {
      return leftId;
   }
   
   public Object getRightId() {
      return rightId;
   }
   
   public boolean equals(Object obj) {
      if(obj instanceof RelationPair) {
         RelationPair pair = (RelationPair) obj;
         
         // check left==left and right==right
         if(leftCMRField == pair.leftCMRField && 
               rightCMRField == pair.rightCMRField &&
               leftId.equals(pair.leftId) && 
               rightId.equals(pair.rightId)) {
            return true;
         }
         
         // check left==right and right==left
         if(leftCMRField == pair.rightCMRField && 
               rightCMRField == pair.leftCMRField &&
               leftId.equals(pair.rightId) && 
               rightId.equals(pair.leftId)) {
            return true;
         }
      }
      return false;
   }
   
   public int hashCode() {
      return leftId.hashCode() ^ rightId.hashCode();
   }
}   

