ContainerPoolFactory


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19  
20  package org.apache.cayenne.conn;
21  
22  import java.util.Hashtable  ;
23  
24  import javax.naming.Context  ;
25  import javax.naming.Name  ;
26  import javax.naming.RefAddr  ;
27  import javax.naming.Reference  ;
28  import javax.naming.spi.ObjectFactory  ;
29  
30  
31  /**
32   * <p>Basic JNDI object factory that creates an instance of
33   * <code>PoolManager</code> that has been configured based on the
34   * <code>RefAddr</code> values of the specified <code>Reference</code>.</p>
35   *
36   * <p>Here is a sample Tomcat 4.x configuration that sets this class
37   * as a default factory for javax.sql.DataSource objects:</p>
38  <code><pre>
39  &lt;ResourceParams name="jdbc/mydb"&gt;
40      &lt;parameter&gt;
41          &lt;name&gt;factory&lt;/name&gt;
42          &lt;value>org.apache.cayenne.conn.ContainerPoolFactory&lt;/value&gt;
43      &lt;/parameter&gt;
44  
45      &lt;parameter>
46          &lt;name>username&lt;/name>
47          &lt;value>andrei&lt;/value>
48      &lt;/parameter>
49              
50      &lt;parameter>
51          &lt;name>password&lt;/name>
52          &lt;value>bla-bla&lt;/value>
53      &lt;/parameter>
54                  
55      &lt;parameter>
56          &lt;name>driver&lt;/name>
57          &lt;value>org.gjt.mm.mysql.Driver&lt;/value>
58      &lt;/parameter>
59              
60      &lt;parameter>
61          &lt;name>url&lt;/name>
62          &lt;value>jdbc:mysql://noise/cayenne&lt;/value>
63      &lt;/parameter>
64              
65      &lt;parameter>
66          &lt;name>min&lt;/name>
67          &lt;value>1&lt;/value>
68      &lt;/parameter>
69              
70      &lt;parameter>
71          &lt;name>max&lt;/name>
72          &lt;value>3&lt;/value>
73      &lt;/parameter>
74  &lt;/ResourceParams>
75  </pre></code>
76   *
77   * <p>After ContainerPoolFactory was configured to be used within the container 
78   * (see above for Tomcat example), you can reference your "jdbc/mydb" DataSource in
79   * web application deployment descriptor like that (per Servlet Specification): </p>
80   *<code><pre>
81  &lt;resource-ref>
82      &lt;es-ref-name>jdbc/mydb&lt;/res-ref-name>
83      &lt;res-type>javax.sql.DataSource&lt;/res-type>
84      &lt;res-auth>Container&lt;/res-auth>
85  &lt;/resource-ref>
86  </pre></code> 
87   *
88   * @author Andrus Adamchik
89   */
90  public class ContainerPoolFactory implements ObjectFactory   {
91  
92      /**
93       * <p>Creates and returns a new <code>PoolManager</code> instance.  If no
94       * instance can be created, returns <code>null</code> instead.</p>
95       *
96       * @param obj The possibly null object containing location or
97       *  reference information that can be used in creating an object
98       * @param name The name of this object relative to <code>nameCtx</code>
99       * @param nameCtx The context relative to which the <code>name</code>
100      *  parameter is specified, or <code>null</code> if <code>name</code>
101      *  is relative to the default initial context
102      * @param environment The possibly null environment that is used in
103      *  creating this object
104      *
105      * @exception Exception if an exception occurs creating the instance
106      */
107     public Object   getObjectInstance(Object   obj, Name   name, Context   nameCtx,
108                                     Hashtable   environment)
109     throws Exception   {
110         // We only know how to deal with <code>javax.naming.Reference</code>s
111         // that specify a class name of "javax.sql.DataSource"
112         if ((obj == null) || !(obj instanceof Reference  )) {
113             return null;
114         }
115 
116         Reference   ref = (Reference  ) obj;
117         if (!"javax.sql.DataSource".equals(ref.getClassName())) {
118             return null;
119         }
120 
121         // Create and configure a PoolManager instance based on the
122         // RefAddr values associated with this Reference
123         RefAddr   ra = null;
124         String   driver = null;
125         String   url = null;
126         int min = 1;
127         int max = 1;
128         String   username = null;
129         String   password = null;
130         
131         ra = ref.get("min");
132         if (ra != null) {
133             min = Integer.parseInt(ra.getContent().toString());
134         }
135         
136         ra = ref.get("max");
137         if (ra != null) {
138             max = Integer.parseInt(ra.getContent().toString());
139         }
140 
141 
142         ra = ref.get("driver");
143         if (ra != null) {
144             driver = ra.getContent().toString();
145         }
146 
147 
148         ra = ref.get("password");
149         if (ra != null) {
150             password = ra.getContent().toString();
151         }
152 
153         ra = ref.get("url");
154         if (ra != null) {
155             url = ra.getContent().toString();
156         }
157 
158         ra = ref.get("username");
159         if (ra != null) {
160             username = ra.getContent().toString();
161         }
162 
163         return new PoolManager(driver, url, min, max, username, password);
164     }
165 }
166 
167
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