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Java > Open Source Codes > org > apache > ojb > broker > accesslayer > sql > SqlSelectByPkStatement


1 package org.apache.ojb.broker.accesslayer.sql;
2
3 /* Copyright 2002-2005 The Apache Software Foundation
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17
18 import org.apache.ojb.broker.metadata.ClassDescriptor;
19 import org.apache.ojb.broker.metadata.FieldDescriptor;
20 import org.apache.ojb.broker.platforms.Platform;
21 import org.apache.ojb.broker.query.Criteria;
22 import org.apache.ojb.broker.query.Query;
23 import org.apache.ojb.broker.query.QueryByCriteria;
24 import org.apache.ojb.broker.util.logging.Logger;
25
26 /**
27  * Model a SELECT Statement by Primary Key
28  *
29  * @author <a HREF="mailto:jbraeuchi@gmx.ch">Jakob Braeuchi</a>
30  * @version $Id: SqlSelectByPkStatement.java,v 1.8.2.4 2005/12/22 18:25:51 brj Exp $
31  */
32
33 public class SqlSelectByPkStatement extends SqlSelectStatement
34 {
35     /**
36      * Constructor for SqlSelectByPkStatement.
37      *
38      * @param cld
39      * @param logger
40      */
41     public SqlSelectByPkStatement(Platform pf, ClassDescriptor cld, Logger logger)
42     {
43         super(pf, cld, buildQuery(cld), logger);
44     }
45
46     /**
47      * Build a Pk-Query base on the ClassDescriptor.
48      *
49      * @param cld
50      * @return a select by PK query
51      */
52     private static Query buildQuery(ClassDescriptor cld)
53     {
54         FieldDescriptor[] pkFields = cld.getPkFields();
55         Criteria crit = new Criteria();
56
57         for(int i = 0; i < pkFields.length; i++)
58         {
59             crit.addEqualTo(pkFields[i].getAttributeName(), null);
60         }
61         return new QueryByCriteria(cld.getClassOfObject(), crit);
62     }
63 }
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