1 /*
2 * Hibernate, Relational Persistence for Idiomatic Java
3 *
4 * Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
5 * indicated by the @author tags or express copyright attribution
6 * statements applied by the authors. All third-party contributions are
7 * distributed under license by Red Hat Middleware LLC.
8 *
9 * This copyrighted material is made available to anyone wishing to use, modify,
10 * copy, or redistribute it subject to the terms and conditions of the GNU
11 * Lesser General Public License, as published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
16 * for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public License
19 * along with this distribution; if not, write to:
20 * Free Software Foundation, Inc.
21 * 51 Franklin Street, Fifth Floor
22 * Boston, MA 02110-1301 USA
23 *
24 */
25 package org.hibernate.loader.entity;
26
27 import java.sql.ResultSet;
28 import java.sql.SQLException;
29 import java.util.List;
30 import java.util.Map;
31
32 import org.slf4j.Logger;
33 import org.slf4j.LoggerFactory;
34 import org.hibernate.HibernateException;
35 import org.hibernate.LockMode;
36 import org.hibernate.MappingException;
37 import org.hibernate.engine.SessionFactoryImplementor;
38 import org.hibernate.engine.SessionImplementor;
39 import org.hibernate.loader.JoinWalker;
40 import org.hibernate.loader.OuterJoinLoader;
41 import org.hibernate.persister.collection.QueryableCollection;
42 import org.hibernate.persister.entity.OuterJoinLoadable;
43 import org.hibernate.transform.ResultTransformer;
44 import org.hibernate.type.Type;
45 import org.hibernate.util.ArrayHelper;
46
47 /**
48 *
49 *
50 * @author Gavin King
51 */
52 public class CollectionElementLoader extends OuterJoinLoader {
53
54 private static final Logger log = LoggerFactory.getLogger(CollectionElementLoader.class);
55
56 private final OuterJoinLoadable persister;
57 private final Type keyType;
58 private final Type indexType;
59 private final String entityName;
60
61 public CollectionElementLoader(
62 QueryableCollection collectionPersister,
63 SessionFactoryImplementor factory,
64 Map enabledFilters)
65 throws MappingException {
66 super(factory, enabledFilters);
67
68 this.keyType = collectionPersister.getKeyType();
69 this.indexType = collectionPersister.getIndexType();
70 this.persister = (OuterJoinLoadable) collectionPersister.getElementPersister();
71 this.entityName = persister.getEntityName();
72
73 JoinWalker walker = new EntityJoinWalker(
74 persister,
75 ArrayHelper.join(
76 collectionPersister.getKeyColumnNames(),
77 collectionPersister.getIndexColumnNames()
78 ),
79 1,
80 LockMode.NONE,
81 factory,
82 enabledFilters
83 );
84 initFromWalker( walker );
85
86 postInstantiate();
87
88 log.debug( "Static select for entity " + entityName + ": " + getSQLString() );
89
90 }
91
92 public Object loadElement(SessionImplementor session, Object key, Object index)
93 throws HibernateException {
94
95 List list = loadEntity(
96 session,
97 key,
98 index,
99 keyType,
100 indexType,
101 persister
102 );
103
104 if ( list.size()==1 ) {
105 return list.get(0);
106 }
107 else if ( list.size()==0 ) {
108 return null;
109 }
110 else {
111 if ( getCollectionOwners()!=null ) {
112 return list.get(0);
113 }
114 else {
115 throw new HibernateException("More than one row was found");
116 }
117 }
118
119 }
120
121 protected Object getResultColumnOrRow(
122 Object[] row,
123 ResultTransformer transformer,
124 ResultSet rs, SessionImplementor session)
125 throws SQLException, HibernateException {
126 return row[row.length-1];
127 }
128
129 protected boolean isSingleRowLoader() {
130 return true;
131 }
132
133
134 }
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