001 package org.apache.ojb.broker.query;
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 java.util.Collection;
019 import java.util.HashSet;
020 import java.util.Vector;
021
022 import org.apache.ojb.broker.metadata.ClassDescriptor;
023 import org.apache.ojb.broker.metadata.DescriptorRepository;
024 import org.apache.ojb.broker.metadata.FieldDescriptor;
025 import org.apache.ojb.broker.metadata.MetadataManager;
026
027 /**
028 * Insert the type's description here.
029 * @author <a href="mailto:thma@apache.org">Thomas Mahler<a>
030 * @version $Id: QueryFactory.java,v 1.1 2007-08-24 22:17:36 ewestfal Exp $
031 */
032 public final class QueryFactory
033 {
034 private static DescriptorRepository getRepository()
035 {
036 return MetadataManager.getInstance().getRepository();
037 }
038
039 /**
040 * create a new ReportQueryByCriteria
041 * @param classToSearchFrom
042 * @param criteria
043 * @param distinct
044 * @return ReportQueryByCriteria
045 */
046 public static ReportQueryByCriteria newReportQuery(Class classToSearchFrom, String[] columns, Criteria criteria, boolean distinct)
047 {
048 criteria = addCriteriaForOjbConcreteClasses(getRepository().getDescriptorFor(classToSearchFrom), criteria);
049 return new ReportQueryByCriteria(classToSearchFrom, columns, criteria, distinct);
050 }
051
052 /**
053 * create a new ReportQueryByCriteria
054 * @param classToSearchFrom
055 * @param criteria
056 * @param distinct
057 * @return ReportQueryByCriteria
058 */
059 public static ReportQueryByCriteria newReportQuery(Class classToSearchFrom, Criteria criteria, boolean distinct)
060 {
061 criteria = addCriteriaForOjbConcreteClasses(getRepository().getDescriptorFor(classToSearchFrom), criteria);
062 return newReportQuery(classToSearchFrom, null, criteria, distinct);
063 }
064
065 /**
066 * create a new ReportQueryByCriteria
067 * @param classToSearchFrom
068 * @param criteria
069 * @return ReportQueryByCriteria
070 */
071 public static ReportQueryByCriteria newReportQuery(Class classToSearchFrom, Criteria criteria)
072 {
073 return newReportQuery(classToSearchFrom, criteria, false);
074 }
075
076 /**
077 * Method declaration
078 * @param classToSearchFrom
079 * @param criteria
080 * @param distinct
081 * @return QueryByCriteria
082 */
083 public static QueryByCriteria newQuery(Class classToSearchFrom, Criteria criteria, boolean distinct)
084 {
085 criteria = addCriteriaForOjbConcreteClasses(getRepository().getDescriptorFor(classToSearchFrom), criteria);
086 return new QueryByCriteria(classToSearchFrom, criteria, distinct);
087 }
088
089 /**
090 * Method declaration
091 * @param classToSearchFrom
092 * @param criteria
093 * @return QueryByCriteria
094 */
095 public static QueryByCriteria newQuery(Class classToSearchFrom, Criteria criteria)
096 {
097 return newQuery(classToSearchFrom, criteria, false);
098 }
099
100 /**
101 * Return a QueryByIdentity for example_or_identity
102 * @param example_or_identity
103 * @return QueryByIdentity
104 */
105 public static QueryByIdentity newQuery(Object example_or_identity)
106 {
107 return newQueryByIdentity(example_or_identity);
108 }
109
110 /**
111 * Return a QueryByIdentity for example_or_identity
112 * @param example_or_identity
113 * @return QueryByIdentity
114 */
115 public static QueryByIdentity newQueryByIdentity(Object example_or_identity)
116 {
117 return new QueryByIdentity(example_or_identity);
118 }
119
120 /**
121 * Return a QueryByCriteria for example
122 * <br>Use with care because building of Query is not foolproof !!!
123 * @param example
124 * @return QueryByCriteria
125 */
126 public static QueryByCriteria newQueryByExample(Object example)
127 {
128 return new QueryByCriteria(example);
129 }
130
131 /**
132 * @param classToSearchFrom
133 * @param indirectionTable
134 * @param criteria
135 * @param distinct
136 * @return QueryByMtoNCriteria
137 */
138 public static QueryByMtoNCriteria newQuery(Class classToSearchFrom, String indirectionTable, Criteria criteria, boolean distinct)
139 {
140 criteria = addCriteriaForOjbConcreteClasses(getRepository().getDescriptorFor(classToSearchFrom), criteria);
141 return new QueryByMtoNCriteria(classToSearchFrom, indirectionTable, criteria, distinct);
142 }
143
144 /**
145 * @param classToSearchFrom
146 * @param indirectionTable
147 * @param criteria
148 * @return QueryByCriteria
149 */
150 public static QueryByCriteria newQuery(Class classToSearchFrom, String indirectionTable, Criteria criteria)
151 {
152 criteria = addCriteriaForOjbConcreteClasses(getRepository().getDescriptorFor(classToSearchFrom), criteria);
153 return new QueryByMtoNCriteria(classToSearchFrom, indirectionTable, criteria);
154 }
155
156 /**
157 * Factory method for QueryBySQL
158 * @param classToSearchFrom
159 * @param anSqlStatement
160 * @return QueryBySQL
161 */
162 public static QueryBySQL newQuery(Class classToSearchFrom, String anSqlStatement)
163 {
164 return new QueryBySQL(classToSearchFrom, anSqlStatement);
165 }
166
167 /**
168 * Searches the class descriptor for the ojbConcrete class attribute
169 * if it finds the concrete class attribute, append a where clause which
170 * specifies we can load all classes that are this type or extents of this type.
171 * @param cld
172 * @return the extent classes
173 */
174 private static Collection getExtentClasses(ClassDescriptor cld)
175 {
176 /**
177 * 1. check if this class has a ojbConcreteClass attribute
178 */
179 FieldDescriptor fd = cld.getFieldDescriptorByName(ClassDescriptor.OJB_CONCRETE_CLASS);
180 Collection classes = new HashSet(); // use same class only once
181 if (fd != null)
182 {
183 classes.add(cld.getClassOfObject().getName());
184 }
185
186 /**
187 * 2. if this class has extents/is an extent search for all extents
188 */
189 if (cld.isExtent())
190 {
191 Vector extentClasses = cld.getExtentClasses();
192
193 /**
194 * 3. get all extents for this class
195 */
196 for (int i = 0; i < extentClasses.size(); i++)
197 {
198 Class ec = (Class) extentClasses.get(i);
199 ClassDescriptor extCld = cld.getRepository().getDescriptorFor(ec);
200 classes.addAll(getExtentClasses(extCld));
201 }
202 }
203
204 return classes;
205 }
206
207 /**
208 * Searches the class descriptor for the ojbConcrete class attribute
209 * if it finds the concrete class attribute, append a where clause which
210 * specifies we can load all classes that are this type or extents of this type.
211 * @param cld
212 * @param crit
213 * @return the passed in Criteria object + optionally and'ed criteria with OR'd class
214 * type discriminators.
215 */
216 private static Criteria addCriteriaForOjbConcreteClasses(ClassDescriptor cld, Criteria crit)
217 {
218 /**
219 * 1. check if this class has a ojbConcreteClass attribute
220 */
221 Criteria concreteClassDiscriminator = null;
222 Collection classes = getExtentClasses(cld);
223
224 /**
225 * 1. create a new Criteria for objConcreteClass
226 */
227 if (!classes.isEmpty())
228 {
229 concreteClassDiscriminator = new Criteria();
230 if (classes.size() > 1)
231 {
232 concreteClassDiscriminator = new Criteria();
233 concreteClassDiscriminator.addIn(ClassDescriptor.OJB_CONCRETE_CLASS, classes);
234 }
235 else
236 {
237 concreteClassDiscriminator.addEqualTo(ClassDescriptor.OJB_CONCRETE_CLASS, classes.toArray()[0]);
238 }
239 }
240
241 /**
242 * 2. only add the AND (objConcreteClass = "some.class" OR....) if we've actually found concrete
243 * classes.
244 */
245 if (concreteClassDiscriminator != null)
246 {
247 /**
248 * it's possible there is no criteria attached to the query, and in this
249 * case we still have to add the IN/EqualTo criteria for the concrete class type
250 * so check if the crit is null and then create a blank one if needed.
251 */
252 if (crit == null)
253 {
254 crit = new Criteria();
255 }
256
257 crit.addAndCriteria(concreteClassDiscriminator);
258 }
259 /**
260 * will just return the passed in criteria if no OJB concrete class is attribute is found.
261 */
262 return crit;
263 }
264
265 }