001 package org.apache.ojb.broker.accesslayer;
002
003 /* Copyright 2002-2005 The Apache Software Foundation
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 import org.apache.ojb.broker.PersistenceBrokerException;
019 import org.apache.ojb.broker.core.PersistenceBrokerImpl;
020 import org.apache.ojb.broker.metadata.ClassDescriptor;
021 import org.apache.ojb.broker.metadata.CollectionDescriptor;
022 import org.apache.ojb.broker.metadata.ObjectReferenceDescriptor;
023
024 /**
025 * Factory for Relationship Prefetchers
026 *
027 * @author <a href="mailto:jbraeuchi@gmx.ch">Jakob Braeuchi</a>
028 * @version $Id: RelationshipPrefetcherFactory.java,v 1.1 2007-08-24 22:17:30 ewestfal Exp $
029 */
030 public class RelationshipPrefetcherFactory
031 {
032 private PersistenceBrokerImpl broker;
033
034 public RelationshipPrefetcherFactory(final PersistenceBrokerImpl broker)
035 {
036 this.broker = broker;
037 }
038
039 /**
040 * create either a CollectionPrefetcher or a ReferencePrefetcher
041 */
042 public RelationshipPrefetcher createRelationshipPrefetcher(ObjectReferenceDescriptor ord)
043 {
044 if (ord instanceof CollectionDescriptor)
045 {
046 CollectionDescriptor cds = (CollectionDescriptor)ord;
047 if (cds.isMtoNRelation())
048 {
049 return new MtoNCollectionPrefetcher(broker, cds);
050 }
051 else
052 {
053 return new CollectionPrefetcher(broker, cds);
054 }
055 }
056 else
057 {
058 return new ReferencePrefetcher(broker, ord);
059 }
060 }
061
062 /**
063 * create either a CollectionPrefetcher or a ReferencePrefetcher
064 */
065 public RelationshipPrefetcher createRelationshipPrefetcher(ClassDescriptor anOwnerCld, String aRelationshipName)
066 {
067 ObjectReferenceDescriptor ord;
068
069 ord = anOwnerCld.getCollectionDescriptorByName(aRelationshipName);
070 if (ord == null)
071 {
072 ord = anOwnerCld.getObjectReferenceDescriptorByName(aRelationshipName);
073 if (ord == null)
074 {
075 throw new PersistenceBrokerException("Relationship named '" + aRelationshipName
076 + "' not found in owner class " + (anOwnerCld != null ? anOwnerCld.getClassNameOfObject() : null));
077 }
078 }
079 return createRelationshipPrefetcher(ord);
080 }
081 }