CachingServiceLocator


1   /*
2    * CachingServiceLocator.java
3    *
4    * Created on March 9, 2005, 1:43 PM
5    */
6   package league.ejb;
7   
8   import java.util.HashMap  ;
9   import java.util.Map  ;
10  import java.util.Collections  ;
11  import java.net.URL  ;
12  
13  import javax.ejb.EJBHome  ;
14  import javax.ejb.EJBLocalHome  ;
15  import javax.jms.ConnectionFactory  ;
16  import javax.jms.Destination  ;
17  import javax.naming.InitialContext  ;
18  import javax.naming.NamingException  ;
19  import javax.rmi.PortableRemoteObject  ;
20  import javax.sql.DataSource  ;
21  
22  /**
23   *
24   * @author honza
25   * @version
26   */
27  public class CachingServiceLocator {
28      
29      private InitialContext   ic;
30      private Map   cache;
31      
32      private static CachingServiceLocator me;
33      
34      static {
35          try {
36              me = new CachingServiceLocator();
37          } catch(NamingException   se) {
38              throw new RuntimeException  (se);
39          }
40      }
41      
42      private CachingServiceLocator() throws NamingException    {
43          ic = new InitialContext  ();
44          cache = Collections.synchronizedMap(new HashMap  ());
45      }
46      
47      public static CachingServiceLocator getInstance() {
48          return me;
49      }
50      
51      private Object   lookup(String   jndiName) throws NamingException   {
52          Object   cachedObj = cache.get(jndiName);
53          if (cachedObj == null) {
54              cachedObj = ic.lookup(jndiName);
55              cache.put(jndiName, cachedObj);
56          }
57          return cachedObj;
58      }
59      
60      /**
61       * will get the ejb Local home factory. If this ejb home factory has already been
62       * clients need to cast to the type of EJBHome they desire
63       *
64       * @return the EJB Home corresponding to the homeName
65       */
66      public EJBLocalHome   getLocalHome(String   jndiHomeName) throws NamingException   {
67          return (EJBLocalHome  ) lookup(jndiHomeName);
68      }
69      
70      /**
71       * will get the ejb Remote home factory. If this ejb home factory has already been
72       * clients need to cast to the type of EJBHome they desire
73       *
74       * @return the EJB Home corresponding to the homeName
75       */
76      public EJBHome   getRemoteHome(String   jndiHomeName, Class   className) throws NamingException   {
77          Object   objref = lookup(jndiHomeName);
78          return (EJBHome  ) PortableRemoteObject.narrow(objref, className);
79      }
80      
81      /**
82       * This method helps in obtaining the topic factory
83       * @return the factory for the factory to get topic connections from
84       */
85      public ConnectionFactory   getConnectionFactory(String   connFactoryName) throws NamingException   {
86          return (ConnectionFactory  ) lookup(connFactoryName);
87      }
88      
89      /**
90       * This method obtains the topc itself for a caller
91       * @return the Topic Destination to send messages to
92       */
93      public Destination   getDestination(String   destName) throws NamingException   {
94          return (Destination  ) lookup(destName);
95      }
96      
97      /**
98       * This method obtains the datasource
99       * @return the DataSource corresponding to the name parameter
100      */
101     public DataSource   getDataSource(String   dataSourceName) throws NamingException   {
102         return (DataSource  ) lookup(dataSourceName);
103     }
104     
105     /**
106      * @return the URL value corresponding
107      * to the env entry name.
108      */
109     public URL   getUrl(String   envName) throws NamingException   {
110         return (URL  ) lookup(envName);
111     }
112     
113     /**
114      * @return the boolean value corresponding
115      * to the env entry such as SEND_CONFIRMATION_MAIL property.
116      */
117     public boolean getBoolean(String   envName) throws NamingException   {
118         Boolean   bool = (Boolean  ) lookup(envName);
119         return bool.booleanValue();
120     }
121     
122     /**
123      * @return the String value corresponding
124      * to the env entry name.
125      */
126     public String   getString(String   envName) throws NamingException   {
127         return (String  ) lookup(envName);
128     }
129 }
130 
131
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