JNDIDependencyItem.java

/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2009, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.switchboard.mc.dependency;

import javax.naming.Binding;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NameNotFoundException;
import javax.naming.NamingException;
import javax.naming.event.EventContext;
import javax.naming.event.NamespaceChangeListener;
import javax.naming.event.NamingEvent;
import javax.naming.event.NamingExceptionEvent;

import org.jboss.dependency.plugins.AbstractDependencyItem;
import org.jboss.dependency.spi.Controller;
import org.jboss.dependency.spi.ControllerState;
import org.jboss.logging.Logger;
import org.jboss.reloaded.naming.CurrentComponent;
import org.jboss.reloaded.naming.spi.JavaEEComponent;
import org.jboss.switchboard.mc.SwitchBoardImpl;

/**
 * JNDIDependencyItem
 *
 * @author Jaikiran Pai
 * @version $Revision: $
 */
public class JNDIDependencyItem extends AbstractDependencyItem implements NamespaceChangeListener 
{

   private static Logger logger = Logger.getLogger(JNDIDependencyItem.class);
   
   private SwitchBoardImpl switchBoard;

   private String jndiName;
   
   private Context globalContext;
   
   public JNDIDependencyItem(SwitchBoardImpl switchBoard, String jndiName, ControllerState whenRequired, ControllerState dependentState)
   {
      this(switchBoard, jndiName, whenRequired, dependentState, false);
   }

   public JNDIDependencyItem(SwitchBoardImpl switchBoard, String jndiName, ControllerState whenRequired, ControllerState dependentState, boolean resolved)
   {
      super(jndiName, jndiName, whenRequired, dependentState);
      this.switchBoard = switchBoard;
      this.jndiName = jndiName;
      this.setResolved(resolved);
      
      //this.tryRegisterNamingListener();
   }

   
   @Override
   public boolean resolve(Controller controller)
   {
      if (this.isResolved())
      {
         return true;
      }
      JavaEEComponent javaeeComp = this.switchBoard.getJavaEEComponent();
      if (javaeeComp == null)
      {
         // mark as unresolved
         this.setResolved(false);
         return this.isResolved();
      }
      CurrentComponent.push(javaeeComp);
      // The call to dependency resolution happens from within MC and the 
      // TCCL (which the naming server uses for returning the proxies in case of 
      // call by value) won't be correct. So set the correct TCCL (== DU CL which can be
      // picked up from the switchboard) before doing the lookup
      ClassLoader oldTCCL = Thread.currentThread().getContextClassLoader();
      Thread.currentThread().setContextClassLoader(this.switchBoard.getClassLoader());
      try
      {
         this.getGlobalContext().lookup(jndiName);
         // mark as resolved
         this.setResolved(true);
         logger.debug("Resolved jndi-name dependency: " + this.jndiName + " based on jndi lookup for switchboard: " + this.switchBoard.getId());
      }
      catch (NameNotFoundException nnfe)
      {
         // mark as unresolved
         this.setResolved(false);
      }
      catch (NamingException ne)
      {
         throw new RuntimeException("Exception during resolving jndi dependency for jndi name: " + this.jndiName
               + " for JavaEEComponent " + javaeeComp.getName(), ne);
      }
      finally
      {
         CurrentComponent.pop();
         Thread.currentThread().setContextClassLoader(oldTCCL);
      }

      // return the resolution status
      return this.isResolved();
   }

   @Override
   public void objectAdded(NamingEvent namingEvent)
   {
      Binding binding = namingEvent.getNewBinding();
      String boundJNDIName = binding.getName();
      if (logger.isTraceEnabled())
      {
         logger.trace(this + " received OBJECT_ADDED event for jndi-name: " + boundJNDIName);
      }
      if (this.jndiName.equals(boundJNDIName))
      {
         this.setResolved(true);
         logger.debug("Resolved jndi-name dependency: " + this.jndiName + " based on naming event for switchboard: " + this.switchBoard.getId());
      }
   }

   @Override
   public void objectRemoved(NamingEvent namingEvent)
   {
      Binding binding = namingEvent.getNewBinding();
      String removedJNDIName = binding.getName();
      if (logger.isTraceEnabled())
      {
         logger.trace(this + " received OBJECT_REMOVED event for jndi-name: " + removedJNDIName);
      }
      if (this.jndiName.equals(removedJNDIName))
      {
         this.setResolved(false);
         logger.debug("Naming event received, jndi-name dependency: " + this.jndiName + " un-bound for switchboard: " + this.switchBoard.getId());
      }
   }

   @Override
   public void objectRenamed(NamingEvent evt)
   {
      // TODO Auto-generated method stub
      
   }

   @Override
   public void namingExceptionThrown(NamingExceptionEvent evt)
   {
      logger.error("NamingException thrown while listening for jndi binding events for jndi name: " + this.jndiName, evt.getException());
   }

   @Override
   public String toString()
   {
      StringBuilder sb = new StringBuilder();
      
      sb.append(this.getClass().getSimpleName());
      sb.append("[jndi-name:");
      sb.append(this.jndiName);
      sb.append("switchboard id:");
      sb.append(this.switchBoard.getId());
      sb.append("]");
      
      return sb.toString();
   }
   
   private Context getGlobalContext() throws NamingException
   {
      if (this.globalContext == null)
      {
         this.globalContext = new InitialContext();
      }
      return this.globalContext;
   }

   private void tryRegisterNamingListener()
   {
      try
      {
         Context globalCtx = this.getGlobalContext();
         Context ctx = (Context) globalCtx.lookup("");
         if (ctx instanceof EventContext)
         {
            EventContext eventCtx = (EventContext) ctx;
            eventCtx.addNamingListener(this.jndiName, EventContext.SUBTREE_SCOPE, this);
            logger.debug("Using naming event based dependency resolver for jndi-name: " + jndiName + " for switchboard: " + this.switchBoard.getId());
         }
      }
      catch (Throwable t)
      {
         // log and ignore
         if (logger.isTraceEnabled())
         {
            logger.trace("**** Exception stacktrace can be ignored **** Could not register naming listener for jndi-name: "
                        + this.jndiName + " for switchboard: " + this.switchBoard.getId(), t);
         }
      }
      
   }
}