Source code: org/objectstyle/cayenne/access/util/RelationshipFault.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
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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
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46 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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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.io.Serializable;
59 import java.util.List;
60
61 import org.objectstyle.cayenne.CayenneRuntimeException;
62 import org.objectstyle.cayenne.DataObject;
63 import org.objectstyle.cayenne.access.DataContext;
64 import org.objectstyle.cayenne.map.ObjEntity;
65 import org.objectstyle.cayenne.map.Relationship;
66 import org.objectstyle.cayenne.query.SelectQuery;
67
68 /**
69 * This class represents a placeholder for an unresolved relationship from a source object.
70 * RelationshipFault is used in cases when it is impossible to create a HOLLOW object using
71 * the information from the relationship source object. These cases include dependent to-one
72 * relationships and flattened to-one relationships.
73 *
74 * @since 1.0.1
75 * @author Andrei Adamchik
76 */
77 public class RelationshipFault implements Serializable {
78 protected String relationshipName;
79 protected DataObject sourceObject;
80
81 public RelationshipFault(DataObject sourceObject, String relationshipName) {
82 this.relationshipName = relationshipName;
83 this.sourceObject = sourceObject;
84 }
85
86 public String getRelationshipName() {
87 return relationshipName;
88 }
89
90 public DataObject getSourceObject() {
91 return sourceObject;
92 }
93
94 /**
95 * Resolves this fault to a DataObject.
96 */
97 public DataObject resolveToOne() {
98 DataContext context = sourceObject.getDataContext();
99 SelectQuery select =
100 QueryUtils.selectRelationshipObjects(context, sourceObject, relationshipName);
101 select.setFetchLimit(2);
102
103 List objects = context.performQuery(select);
104
105 if (objects.isEmpty()) {
106 return null;
107 }
108 else if (objects.size() == 1) {
109 return (DataObject) objects.get(0);
110 }
111 else {
112 ObjEntity entity = faultEntity();
113 String label = (entity != null) ? entity.getName() : "Unknown";
114 throw new CayenneRuntimeException(
115 "Error resolving to-one fault. "
116 + "More than one object found. "
117 + "Fault entity: "
118 + label);
119 }
120 }
121
122 /**
123 * Determines ObjEntity of this fault.
124 */
125 protected ObjEntity faultEntity() {
126 DataContext context = sourceObject.getDataContext();
127 ObjEntity srcEntity = context.getEntityResolver().lookupObjEntity(sourceObject);
128 Relationship relationship = srcEntity.getRelationship(relationshipName);
129
130 if (relationship == null) {
131 throw new IllegalStateException(
132 "Non-existent relationship: " + relationshipName);
133 }
134
135 return (ObjEntity) relationship.getTargetEntity();
136 }
137 }