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1   /***
2    * SQLExceptionHandlerFactory.java
3    *
4    * This file is part of the creme library.
5    * The creme library intends to ease the development effort of large
6    * applications by providing easy to use support classes.
7    *
8    * Copyright (C) 2004 Denis Bregeon
9    *
10   * This library is free software; you can redistribute it and/or
11   * modify it under the terms of the GNU Lesser General Public
12   * License as published by the Free Software Foundation; either
13   * version 2.1 of the License, or (at your option) any later version.
14   *
15   * This library is distributed in the hope that it will be useful,
16   * but WITHOUT ANY WARRANTY; without even the implied warranty of
17   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18   * Lesser General Public License for more details.
19   *
20   * You should have received a copy of the GNU Lesser General Public
21   * License along with this library; if not, write to the Free Software
22   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
23   *
24   * contact information: dbregeon@sourceforge.net
25   */
26  package org.jcreme.sql;
27  
28  import java.util.Hashtable;
29  
30  /***
31   * This class enables to build a SQLExceptionHandler when needed from the name
32   * of the vendor.
33   * 
34   * @author $Author: dbregeon $
35   * @version $Revision: 1.1 $
36   */
37  public class SQLExceptionHandlerFactory {
38      /***
39       * The unique instance of this class.
40       */
41      private static SQLExceptionHandlerFactory instance = null;
42  
43      /***
44       * Keys are the vendor names, values are the SQLExceptionHandler classes.
45       */
46      private final Hashtable handlerClasses = new Hashtable();
47  
48      /***
49       * Give access to the unique instance of the class.
50       * 
51       * @return the unique instance of the class.
52       */
53      public static SQLExceptionHandlerFactory getInstance() {
54          if (instance == null) {
55              instance = new SQLExceptionHandlerFactory();
56          }
57          return instance;
58      }
59  
60      /***
61       * Enables to associate a SQLExceptionHandler class to a product name. It
62       * silently ignores null and invalid values.
63       * 
64       * @param productName
65       *            the name of the product as returned from the DatabaseMetaData.
66       * @param handlerClass
67       *            the class which instances can handle errors from the product.
68       */
69      public void registerSQLExceptionHandlerClass(String productName,
70              Class handlerClass) {
71          if ((productName != null) && (handlerClass != null)
72                  && (SQLExceptionHandler.class.isAssignableFrom(handlerClass))) {
73              this.handlerClasses.put(productName, handlerClass);
74          }
75      }
76  
77      /***
78       * Builds a new instance of the SQLExceptionHandler class associated to the
79       * product name. If no such class exists, an instance of
80       * DefaultSQLExceptionHandler is returned.
81       * 
82       * @param productName
83       *            the name of the product as returned from the DatabaseMetaData.
84       * @return an instance of a SQLExceptionHandler implementation.
85       */
86      public SQLExceptionHandler buildSQLExceptionHandler(String productName) {
87          SQLExceptionHandler result = null;
88          if (productName != null) {
89              Class clazz = (Class) this.handlerClasses.get(productName);
90              if (clazz != null) {
91                  try {
92                      result = (SQLExceptionHandler) clazz.newInstance();
93                  } catch (InstantiationException e) {
94                      e.printStackTrace();
95                  } catch (IllegalAccessException e) {
96                      e.printStackTrace();
97                  }
98              }
99          }
100         if (result == null) {
101             result = new DefaultSQLExceptionHandler();
102         }
103         return result;
104     }
105 
106 }