Source code: org/objectstyle/cayenne/access/EntityResolver.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;
57
58 import java.util.ArrayList;
59 import java.util.Collection;
60 import java.util.Collections;
61 import java.util.HashMap;
62 import java.util.Iterator;
63 import java.util.List;
64 import java.util.Map;
65
66 import org.objectstyle.cayenne.CayenneRuntimeException;
67 import org.objectstyle.cayenne.DataObject;
68 import org.objectstyle.cayenne.conf.Configuration;
69 import org.objectstyle.cayenne.map.DataMap;
70 import org.objectstyle.cayenne.map.DbEntity;
71 import org.objectstyle.cayenne.map.Entity;
72 import org.objectstyle.cayenne.map.ObjEntity;
73 import org.objectstyle.cayenne.map.Procedure;
74 import org.objectstyle.cayenne.query.Query;
75 import org.objectstyle.cayenne.query.SelectQuery;
76
77 /**
78 * EntityResolver encapsulates resolving between ObjEntities, DbEntities,
79 * DataObject Classes, and Entity names. An instance is typically obtained
80 * from a QueryEngine by getEntityResolver. EntityResolver is thread-safe.
81 *
82 * @author Craig Miskell
83 * @author Andrei Adamchik
84 */
85 public class EntityResolver {
86 protected Map dbEntityCache;
87 protected Map objEntityCache;
88 protected Map procedureCache;
89 protected List maps;
90 protected List mapsRef;
91
92 public EntityResolver() {
93 this.maps = new ArrayList();
94 this.mapsRef = Collections.unmodifiableList(maps);
95 this.dbEntityCache = new HashMap();
96 this.objEntityCache = new HashMap();
97 this.procedureCache = new HashMap();
98 }
99
100 /**
101 * Constructor for EntityResolver.
102 */
103 public EntityResolver(Collection dataMaps) {
104 this();
105 this.maps.addAll(dataMaps); //Take a copy
106 this.constructCache();
107 }
108
109 /**
110 * Adds a DataMap to the list handled by resolver.
111 */
112 public synchronized void addDataMap(DataMap map) {
113 if (!maps.contains(map)) {
114 maps.add(map);
115 clearCache();
116 }
117 }
118
119 public synchronized void removeDataMap(DataMap map) {
120 if (maps.remove(map)) {
121 clearCache();
122 }
123 }
124
125 /**
126 * Returns a DataMap matching the name.
127 */
128 public synchronized DataMap getDataMap(String mapName) {
129 if (mapName == null) {
130 return null;
131 }
132
133 Iterator it = maps.iterator();
134 while (it.hasNext()) {
135 DataMap map = (DataMap) it.next();
136 if (mapName.equals(map.getName())) {
137 return map;
138 }
139 }
140
141 return null;
142 }
143
144 public synchronized void setDataMaps(Collection maps) {
145 this.maps.clear();
146 this.maps.addAll(maps);
147 clearCache();
148 }
149
150 /**
151 * Returns an unmodifiable collection of DataMaps.
152 */
153 public Collection getDataMaps() {
154 return mapsRef;
155 }
156
157 /**
158 * Removes all entity mappings from the cache.
159 * Cache can be rebuilt either explicitly by calling
160 * <code>constructCache</code>, or on demand by calling any of the
161 * <code>lookup...</code> methods.
162 */
163 protected synchronized void clearCache() {
164 dbEntityCache.clear();
165 objEntityCache.clear();
166 procedureCache.clear();
167 }
168
169 /**
170 * Creates caches of DbEntities by ObjEntity,
171 * DataObject class, and ObjEntity name using internal
172 * list of maps.
173 */
174 protected synchronized void constructCache() {
175 clearCache();
176 Iterator mapIterator = maps.iterator();
177 while (mapIterator.hasNext()) {
178 DataMap thisMap = (DataMap) mapIterator.next();
179
180 // index entities
181 Iterator objEntities = thisMap.getObjEntities().iterator();
182 while (objEntities.hasNext()) {
183 ObjEntity oe = (ObjEntity) objEntities.next();
184 DbEntity de = oe.getDbEntity();
185 dbEntityCache.put(oe, de);
186 Class entityClass;
187 try {
188 entityClass =
189 Configuration.getResourceLoader().loadClass(
190 oe.getClassName());
191 } catch (ClassNotFoundException e) {
192 throw new CayenneRuntimeException(
193 "Cannot find class " + oe.getClassName());
194 }
195
196 if (objEntityCache.get(entityClass) != null) {
197 throw new CayenneRuntimeException(
198 getClass().getName()
199 + ": More than one ObjEntity ("
200 + oe.getName()
201 + " and "
202 + ((ObjEntity) objEntityCache.get(entityClass))
203 .getName()
204 + ") uses the class "
205 + entityClass.getName());
206 }
207
208 dbEntityCache.put(entityClass, de);
209 objEntityCache.put(entityClass, oe);
210 dbEntityCache.put(oe.getName(), de);
211 objEntityCache.put(oe.getName(), oe);
212 }
213
214 // index stored procedures
215 Iterator procedures = thisMap.getProcedures().iterator();
216 while (procedures.hasNext()) {
217 Procedure proc = (Procedure) procedures.next();
218 procedureCache.put(proc.getName(), proc);
219 }
220 }
221 }
222
223 /**
224 * Looks in the DataMap's that this object was created with for the DbEntity
225 * that services the specified class
226 * @return the required DbEntity, or null if none matches the specifier
227 */
228 public synchronized DbEntity lookupDbEntity(Class aClass) {
229 return this._lookupDbEntity(aClass);
230 }
231
232 /**
233 * Looks in the DataMap's that this object was created with for the DbEntity
234 * that services the specified objentity
235 * @return the required DbEntity, or null if none matches the specifier
236 */
237 public synchronized DbEntity lookupDbEntity(ObjEntity entity) {
238 return this._lookupDbEntity(entity);
239 }
240
241 /**
242 * Looks in the DataMap's that this object was created with for the DbEntity
243 * that services the class with the given name
244 * @return the required DbEntity, or null if none matches the specifier
245 */
246 public synchronized DbEntity lookupDbEntity(String entityName) {
247 return this._lookupDbEntity(entityName);
248 }
249
250 /**
251 * Looks in the DataMap's that this object was created with for the DbEntity
252 * that services the specified data Object
253 * @return the required DbEntity, or null if none matches the specifier
254 */
255 public synchronized DbEntity lookupDbEntity(DataObject dataObject) {
256 return this._lookupDbEntity(dataObject.getClass());
257 }
258
259 /**
260 * Internal usage only - provides the type-unsafe implementation which services
261 * the four typesafe public lookupDbEntity methods
262 * Looks in the DataMap's that this object was created with for the ObjEntity that maps to the
263 * specified object. Object may be a Entity name, ObjEntity, DataObject class
264 * (Class object for a class which implements the DataObject interface), or a DataObject
265 * instance itself
266 *
267 * @return the required DbEntity, or null if none matches the specifier
268 */
269 private synchronized DbEntity _lookupDbEntity(Object object) {
270 if (object instanceof DbEntity) {
271 return (DbEntity) object;
272 }
273
274 DbEntity result = (DbEntity) dbEntityCache.get(object);
275 if (result == null) {
276 // reconstruct cache just in case some of the datamaps
277 // have changed and now contain the required information
278 constructCache();
279 result = (DbEntity) dbEntityCache.get(object);
280 }
281 return result;
282 }
283
284 /**
285 * Looks up the DbEntity for the given query by using the query's getRoot method and passing to lookupDbEntity
286 * @return the root DbEntity of the query
287 */
288 public synchronized DbEntity lookupDbEntity(Query q) {
289 Object root = q.getRoot();
290 if (root instanceof DbEntity) {
291 return (DbEntity) root;
292 } else if (root instanceof Class) {
293 return this.lookupDbEntity((Class) root);
294 } else if (root instanceof ObjEntity) {
295 return this.lookupDbEntity((ObjEntity) root);
296 } else if (root instanceof String) {
297 return this.lookupDbEntity((String) root);
298 } else if (root instanceof DataObject) {
299 return this.lookupDbEntity((DataObject) root);
300 }
301 return null;
302 }
303
304 /**
305 * Looks in the DataMap's that this object was created with for the ObjEntity that maps to the
306 * services the specified class
307 * @return the required ObjEntity or null if there is none that matches the specifier
308 */
309 public synchronized ObjEntity lookupObjEntity(Class aClass) {
310 return this._lookupObjEntity(aClass);
311 }
312
313 /**
314 * Looks in the DataMap's that this object was created with for the ObjEntity that maps to the
315 * services the class with the given name
316 * @return the required ObjEntity or null if there is none that matches the specifier
317 */
318 public synchronized ObjEntity lookupObjEntity(String entityName) {
319 return this._lookupObjEntity(entityName);
320 }
321
322 /**
323 * Looks in the DataMap's that this object was created with for the ObjEntity
324 * that services the specified data Object
325 * @return the required ObjEntity, or null if none matches the specifier
326 */
327 public synchronized ObjEntity lookupObjEntity(DataObject dataObject) {
328 return this._lookupObjEntity(dataObject.getClass());
329 }
330
331 /**
332 * Internal usage only - provides the type-unsafe implementation which services
333 * the three typesafe public lookupObjEntity methods
334 * Looks in the DataMap's that this object was created with for the ObjEntity that maps to the
335 * specified object. Object may be a Entity name, DataObject instance or DataObject class
336 * (Class object for a class which implements the DataObject interface)
337 *
338 * @return the required ObjEntity or null if there is none that matches the specifier
339 */
340 private synchronized ObjEntity _lookupObjEntity(Object object) {
341 if (object instanceof ObjEntity) {
342 return (ObjEntity) object;
343 }
344
345 if (object instanceof DataObject) {
346 object = object.getClass();
347 }
348
349 ObjEntity result = (ObjEntity) objEntityCache.get(object);
350 if (result == null) {
351 // reconstruct cache just in case some of the datamaps
352 // have changed and now contain the required information
353 constructCache();
354 result = (ObjEntity) objEntityCache.get(object);
355 }
356 return result;
357 }
358
359 /**
360 * Looks up the ObjEntity for the given query by using the query's getRoot method and passing to lookupObjEntity
361 * @return the root ObjEntity of the query
362 * @throws CayenneRuntimeException if the root of the query is a DbEntity (it is not reliably possible to map
363 * from a DbEntity to an ObjEntity as a DbEntity may be the source for multiple ObjEntities. It is not safe
364 * to rely on such behaviour).
365 */
366 public synchronized ObjEntity lookupObjEntity(Query q) {
367
368 Object root = q.getRoot();
369 if (root instanceof DbEntity) {
370 throw new CayenneRuntimeException(
371 "Cannot safely resolve the ObjEntity for the query "
372 + q
373 + " because the root of the query is a DbEntity");
374 } else if (root instanceof ObjEntity) {
375 return (ObjEntity) root;
376 } else if (root instanceof Class) {
377 return this.lookupObjEntity((Class) root);
378 } else if (root instanceof String) {
379 return this.lookupObjEntity((String) root);
380 } else if (root instanceof DataObject) {
381 return this.lookupObjEntity((DataObject) root);
382 }
383 return null;
384 }
385
386 /**
387 * Searches for the named query associated with the ObjEntity corresponding
388 * to the Java class specified. Returns such query if found, null otherwise.
389 */
390 public SelectQuery lookupQuery(Class queryRoot, String queryName) {
391 Entity ent = lookupObjEntity(queryRoot);
392 return (ent != null) ? ent.getQuery(queryName) : null;
393 }
394
395 public Procedure lookupProcedure(Query q) {
396 Object root = q.getRoot();
397 if (root instanceof Procedure) {
398 return (Procedure) root;
399 } else if (root instanceof String) {
400 return this.lookupProcedure((String) root);
401 }
402 return null;
403 }
404
405 public Procedure lookupProcedure(String procedureName) {
406
407 Procedure result = (Procedure) procedureCache.get(procedureName);
408 if (result == null) {
409 // reconstruct cache just in case some of the datamaps
410 // have changed and now contain the required information
411 constructCache();
412 result = (Procedure) procedureCache.get(procedureName);
413 }
414
415 return result;
416 }
417 }