/*
* JBoss, Home of Professional Open Source.
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file 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 java.util.HashSet;
import java.util.Set;
import javax.ejb.EJBException;
import org.jboss.ejb.plugins.cmp.jdbc.bridge.JDBCCMRFieldBridge;
/**
* This class holds data about one relationship. It maintains a lists of
* which relations have been added and removed. When the transaction is
* committed these list are retrieved and used to update the relation table.
*
* @author <a href="mailto:dain@daingroup.com">Dain Sundstrom</a>
* @version $Revision: 81030 $
*/
public final class RelationData
{
private final JDBCCMRFieldBridge leftCMRField;
private final JDBCCMRFieldBridge rightCMRField;
public final Set addedRelations = new HashSet();
public final Set removedRelations = new HashSet();
public final Set notRelatedPairs = new HashSet();
public RelationData(JDBCCMRFieldBridge leftCMRField, JDBCCMRFieldBridge rightCMRField)
{
this.leftCMRField = leftCMRField;
this.rightCMRField = rightCMRField;
}
public JDBCCMRFieldBridge getLeftCMRField()
{
return leftCMRField;
}
public JDBCCMRFieldBridge getRightCMRField()
{
return rightCMRField;
}
public void addRelation(JDBCCMRFieldBridge leftCMRField,
Object leftId,
JDBCCMRFieldBridge rightCMRField,
Object rightId)
{
// only need to bother if neither side has a foreign key
if(!leftCMRField.hasForeignKey() && !rightCMRField.hasForeignKey())
{
RelationPair pair = createRelationPair(leftCMRField, leftId, rightCMRField, rightId);
if(removedRelations.contains(pair))
{
// we were going to remove this relation
// and now we are adding it. Just
// remove it from the remove set and we are ok.
removedRelations.remove(pair);
}
else
{
addedRelations.add(pair);
// if pair was specifically marked as
// not related, remove it to the not
// related set. See below.
if(notRelatedPairs.contains(pair))
{
notRelatedPairs.remove(pair);
}
}
}
}
public void removeRelation(JDBCCMRFieldBridge leftCMRField,
Object leftId,
JDBCCMRFieldBridge rightCMRField,
Object rightId)
{
// only need to bother if neither side has a foreign key
if(!leftCMRField.hasForeignKey() && !rightCMRField.hasForeignKey())
{
RelationPair pair = createRelationPair(leftCMRField, leftId, rightCMRField, rightId);
if(addedRelations.contains(pair))
{
// we were going to add this relation
// and now we are removing it. Just
// remove it from the add set and we are ok.
addedRelations.remove(pair);
// add it to the set of not related pairs
// so if remove is called again it is not
// added to the remove list. This avoids
// an extra 'DELETE FROM...' query.
// This happend when a object is moved from
// one relation to another. See
// JDBCCMRFieldBridge.createRelationLinks
notRelatedPairs.add(pair);
}
else
{
// if pair is related (not not related)
// add it to the remove set. See above.
if(!notRelatedPairs.contains(pair))
{
removedRelations.add(pair);
}
}
}
}
public boolean isDirty()
{
return addedRelations.size() > 0 || removedRelations.size() > 0;
}
private RelationPair createRelationPair(JDBCCMRFieldBridge leftCMRField,
Object leftId,
JDBCCMRFieldBridge rightCMRField,
Object rightId)
{
if(this.leftCMRField == leftCMRField && this.rightCMRField == rightCMRField)
{
return new RelationPair(leftCMRField, leftId, rightCMRField, rightId);
}
if(this.leftCMRField == rightCMRField && this.rightCMRField == leftCMRField)
{
return new RelationPair(rightCMRField, rightId, leftCMRField, leftId);
}
throw new EJBException("Error: cmrFields are of wrong type");
}
}