package org.apache.ojb.broker.core;

 /* Copyright 2003-2005 The Apache Software Foundation

  *

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  *     http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 import java.util.Properties;

 import javax.naming.Context;

 import javax.naming.InitialContext;

 import javax.naming.NamingException;

 import org.apache.ojb.broker.OJBRuntimeException;

 import org.apache.ojb.broker.util.logging.Logger;

 import org.apache.ojb.broker.util.logging.LoggerFactory;

 /**

  * Encapsulates a reference to the JNDI Naming context.

  *

  * @author <a href="mailto:thma@apache.org">Thomas Mahler<a>

  * @version $Id: NamingLocator.java,v 1.1 2007-08-24 22:17:35 ewestfal Exp $

  */

 public class NamingLocator

 {

     private static Logger log = LoggerFactory.getLogger(NamingLocator.class);

     private static Context ctx = null;

     private static Properties prop;

     /**

      * Returns the naming context.

      */

     public static Context getContext()

     {

         if (ctx == null)

         {

             try

             {

                 setContext(null);

             }

             catch (Exception e)

             {

                 log.error("Cannot instantiate the InitialContext", e);

                 throw new OJBRuntimeException(e);

             }

         }

         return ctx;

     }

     /**

      * Lookup an object instance from JNDI context.

      *

      * @param jndiName JNDI lookup name

      * @return Matching object or <em>null</em> if none found.

      */

     public static Object lookup(String jndiName)

     {

         if(log.isDebugEnabled()) log.debug("lookup("+jndiName+") was called");

         try

         {

             return getContext().lookup(jndiName);

         }

         catch (NamingException e)

         {

             throw new OJBRuntimeException("Lookup failed for: " + jndiName, e);

         }

         catch(OJBRuntimeException e)

         {

             throw e;

         }

     }

     /**

      * Refresh the used {@link InitialContext} instance.

      */

     public static void refresh()

     {

         try

         {

             setContext(prop);

         }

         catch (NamingException e)

         {

             log.error("Unable to refresh the naming context");

             throw new OJBRuntimeException("Refresh of context failed, used properties: "

                     + (prop != null ? prop.toString() : "none"), e);

         }

     }

     /**

      * Set the used {@link InitialContext}. If properties argument is <em>null</em>, the default

      * initial context was used.

      *

      * @param properties The properties used for context instantiation - the properties are:

      *  {@link Context#INITIAL_CONTEXT_FACTORY}, {@link Context#PROVIDER_URL}, {@link Context#URL_PKG_PREFIXES}

      * @throws NamingException

      */

     public static synchronized void setContext(Properties properties) throws NamingException

     {

         log.info("Instantiate naming context, properties: " + properties);

         if(properties != null)

         {

             ctx = new InitialContext(properties);

         }

         else

         {

             ctx = new InitialContext();

         }

         prop = properties;

     }

 }