SqlUpdateStatement


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.util.logging.Logger;
21  
22  /**
23   * Model an UPDATE Statement
24   *
25   * @author <a HREF="mailto:jbraeuchi@hotmail.com">Jakob Braeuchi</a>
26   * @version $Id: SqlUpdateStatement.java,v 1.6.2.2 2005/12/21 22:23:44 tomdz Exp $
27   */
28  public class SqlUpdateStatement extends SqlPkStatement
29  {
30      protected String   sql;
31  
32      /**
33       * Constructor for SqlUpdateStatement.
34       *
35       * @param cld
36       * @param logger
37       */
38      public SqlUpdateStatement(ClassDescriptor cld, Logger logger)
39      {
40          super(cld, logger);
41      }
42  
43      /**
44       * generates a SET-phrase for a prepared update statement.
45       *
46       * @param stmt the StringBuffer
47       */
48      private void appendSetClause(ClassDescriptor cld, StringBuffer   stmt)
49      {
50          FieldDescriptor[] fields = cld.getNonPkRwFields();
51  
52          if(fields.length == 0)
53          {
54              return;
55          }
56  
57          stmt.append(" SET ");
58          for(int i = 0; i < fields.length; i++)
59          {
60              stmt.append(fields[i].getColumnName());
61              stmt.append("=?");
62              if(i < fields.length - 1)
63              {
64                  stmt.append(",");
65              }
66          }
67      }
68  
69      /**
70       * @see SqlStatement#getStatement()
71       */
72      public String   getStatement()
73      {
74          if(sql == null)
75          {
76              StringBuffer   stmt = new StringBuffer  (1024);
77              ClassDescriptor cld = getClassDescriptor();
78  
79              stmt.append("UPDATE ");
80              appendTable(cld, stmt);
81              appendSetClause(cld, stmt);
82              appendWhereClause(cld, true, stmt); //use Locking
83  
84              sql = stmt.toString();
85          }
86          return sql;
87      }
88  
89  }
90
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