Source code: org/objectstyle/cayenne/access/util/ContextSelectObserver.java
1 /* ====================================================================
2 *
3 * The ObjectStyle Group Software License, Version 1.0
4 *
5 * Copyright (c) 2002-2003 The ObjectStyle Group
6 * and individual authors of the software. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. The end-user documentation included with the redistribution, if
21 * any, must include the following acknowlegement:
22 * "This product includes software developed by the
23 * ObjectStyle Group (http://objectstyle.org/)."
24 * Alternately, this acknowlegement may appear in the software itself,
25 * if and wherever such third-party acknowlegements normally appear.
26 *
27 * 4. The names "ObjectStyle Group" and "Cayenne"
28 * must not be used to endorse or promote products derived
29 * from this software without prior written permission. For written
30 * permission, please contact andrus@objectstyle.org.
31 *
32 * 5. Products derived from this software may not be called "ObjectStyle"
33 * nor may "ObjectStyle" appear in their names without prior written
34 * permission of the ObjectStyle Group.
35 *
36 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
37 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
38 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
39 * DISCLAIMED. IN NO EVENT SHALL THE OBJECTSTYLE GROUP OR
40 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
42 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
43 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
44 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
45 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
46 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47 * SUCH DAMAGE.
48 * ====================================================================
49 *
50 * This software consists of voluntary contributions made by many
51 * individuals on behalf of the ObjectStyle Group. For more
52 * information on the ObjectStyle Group, please see
53 * <http://objectstyle.org/>.
54 *
55 */
56 package org.objectstyle.cayenne.access.util;
57
58 import java.util.ArrayList;
59 import java.util.Iterator;
60 import java.util.List;
61 import java.util.Map;
62
63 import org.apache.log4j.Level;
64 import org.objectstyle.cayenne.CayenneRuntimeException;
65 import org.objectstyle.cayenne.access.DataContext;
66 import org.objectstyle.cayenne.map.DbEntity;
67 import org.objectstyle.cayenne.map.ObjEntity;
68 import org.objectstyle.cayenne.map.ObjRelationship;
69 import org.objectstyle.cayenne.query.PrefetchSelectQuery;
70 import org.objectstyle.cayenne.query.Query;
71
72 /**
73 * ContextSelectObserver is a SelectObserver that would
74 * convert fetched data rows into objects of an associated
75 * DataContext.
76 */
77 public class ContextSelectObserver extends SelectObserver {
78 protected DataContext context;
79
80 /**
81 * Constructor for ContextSelectObserver.
82 * @param logLevel
83 */
84 public ContextSelectObserver(DataContext context, Level logLevel) {
85 super(logLevel);
86 this.context = context;
87 }
88
89 /**
90 * Overrides superclass behavior to convert each data row to a real
91 * object. Registers objects with parent DataContext.
92 */
93 public void nextDataRows(Query query, List dataRows) {
94 List result = new ArrayList();
95 if (dataRows != null && dataRows.size() > 0) {
96 ObjEntity ent = context.getEntityResolver().lookupObjEntity(query);
97
98 // do a sanity check on ObjEntity... if it's DbEntity has no PK defined,
99 // we can't build a valid ObjectId
100 DbEntity dbEntity = ent.getDbEntity();
101 if(dbEntity == null) {
102 throw new CayenneRuntimeException("ObjEntity '" + ent.getName() + "' has no DbEntity.");
103 }
104
105 if(dbEntity.getPrimaryKey().size() == 0) {
106 throw new CayenneRuntimeException("Can't create ObjectId for '"
107 + ent.getName()
108 + "'. Reason: DbEntity '"
109 + dbEntity.getName()
110 + "' has no Primary Key defined.");
111 }
112
113 Iterator it = dataRows.iterator();
114 while (it.hasNext()) {
115 result.add(
116 context.objectFromDataRow(ent, (Map) it.next(), true));
117 }
118 }
119
120 if (query instanceof PrefetchSelectQuery) {
121 PrefetchSelectQuery prefetchQuery = (PrefetchSelectQuery) query;
122 ObjRelationship theRelationship =
123 prefetchQuery.getSingleStepToManyRelationship();
124 if (theRelationship!= null) {
125 //The root query should have already executed, so we can get it's
126 // results
127 List rootQueryResults =
128 this.getResults(prefetchQuery.getRootQuery());
129 if (rootQueryResults == null) {
130 throw new CayenneRuntimeException(
131 "Prefetch query for path "
132 + prefetchQuery.getPrefetchPath()
133 + " executed before it's root query "
134 + prefetchQuery.getRootQuery());
135 }
136 this
137 .context
138 .getSnapshotManager()
139 .mergePrefetchResultsRelationships(
140 rootQueryResults, theRelationship, result);
141 }
142 }
143
144 super.nextDataRows(query, result);
145 }
146 }