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1   /*
2    * Copyright 2001,2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.apache.commons.scaffold.sql;
18  
19  
20  import java.sql.SQLException;
21  
22  import javax.servlet.http.HttpServlet;
23  import javax.sql.DataSource;
24  
25  
26  /**
27   * Connection adaptor for a connection pool that is exposed
28   * through the servlet context, like the Struts generic
29   * connection pool.
30   * <p>
31   * The ConnectionServlet will automatically set a reference
32   * to itself if an instance of this class is specified
33   * as the ConnectionAdaptor.
34   *
35   * @author Ted Husted
36   * @version $Revision: 155464 $ $Date: 2005-02-26 13:26:54 +0000 (Sat, 26 Feb 2005) $
37   */
38  public class ServletAdaptor extends ConnectionAdaptor {
39  
40  
41      /**
42       * Field to store a link to a servlet in the application.
43       */
44      private static HttpServlet servlet = null;
45  
46  
47      /**
48       * Set a reference to a servlet in the application
49       * to allow access to the servlet context.
50       */
51      public void setServlet(HttpServlet servlet) {
52          ServletAdaptor.servlet = servlet;
53      }
54  
55  
56     /**
57      * Return datasource from the servlet context using
58      * key as the attribute name.
59      *
60      * @param key The attribute name for the resource.
61      * If null is passed, null is returned.
62      * @returns null or the datasource object related to "key"
63      */
64      protected DataSource getDataSource(String key)
65              throws SQLException {
66  
67          if (null==key) return null;
68  
69          return (DataSource)
70              servlet.getServletContext().getAttribute(key);
71  
72      }
73  
74  
75       // Required
76      public ServletAdaptor() {
77  
78          if (null==pool) pool = this;
79  
80      }
81  
82  } // end ServletAdaptor
83