org.hornetq.jms.client.HornetQQueueBrowser Maven / Gradle / Ivy

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This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2005-2014 Red Hat, Inc.
 * Red Hat licenses this file to you 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.
 */
package org.hornetq.jms.client;

import java.util.Enumeration;
import java.util.NoSuchElementException;

import javax.jms.JMSException;
import javax.jms.Queue;
import javax.jms.QueueBrowser;

import org.hornetq.api.core.HornetQException;
import org.hornetq.api.core.SimpleString;
import org.hornetq.api.core.client.ClientConsumer;
import org.hornetq.api.core.client.ClientMessage;
import org.hornetq.api.core.client.ClientSession;

/**
 * HornetQ implementation of a JMS QueueBrowser.
 *
 * @author Tim Fox
 * @author Andy Taylor
 *
 */
public final class HornetQQueueBrowser implements QueueBrowser
{
   // Constants ------------------------------------------------------------------------------------

   // Static ---------------------------------------------------------------------------------------

   // Attributes -----------------------------------------------------------------------------------

   private final ClientSession session;

   private ClientConsumer consumer;

   private final HornetQQueue queue;

   private SimpleString filterString;

   // Constructors ---------------------------------------------------------------------------------

   protected HornetQQueueBrowser(final HornetQQueue queue, final String messageSelector, final ClientSession session) throws JMSException
   {
      this.session = session;
      this.queue = queue;
      if (messageSelector != null)
      {
         filterString = new SimpleString(SelectorTranslator.convertToHornetQFilterString(messageSelector));
      }
   }

   // QueueBrowser implementation -------------------------------------------------------------------

   public void close() throws JMSException
   {
      if (consumer != null)
      {
         try
         {
            consumer.close();
         }
         catch (HornetQException e)
         {
            throw JMSExceptionHelper.convertFromHornetQException(e);
         }
      }
   }

   public Enumeration getEnumeration() throws JMSException
   {
      try
      {
         close();

         consumer = session.createConsumer(queue.getSimpleAddress(), filterString, true);

         return new BrowserEnumeration();
      }
      catch (HornetQException e)
      {
         throw JMSExceptionHelper.convertFromHornetQException(e);
      }

   }

   public String getMessageSelector() throws JMSException
   {
      return filterString == null ? null : filterString.toString();
   }

   public Queue getQueue() throws JMSException
   {
      return queue;
   }

   // Public ---------------------------------------------------------------------------------------

   @Override
   public String toString()
   {
      return "HornetQQueueBrowser->" + consumer;
   }

   // Package protected ----------------------------------------------------------------------------

   // Protected ------------------------------------------------------------------------------------

   // Private --------------------------------------------------------------------------------------

   // Inner classes --------------------------------------------------------------------------------

   private final class BrowserEnumeration implements Enumeration
   {
      ClientMessage current = null;

      public boolean hasMoreElements()
      {
         if (current == null)
         {
            try
            {
               current = consumer.receiveImmediate();
            }
            catch (HornetQException e)
            {
               return false;
            }
         }
         return current != null;
      }

      public HornetQMessage nextElement()
      {
         HornetQMessage msg;
         if (hasMoreElements())
         {
            ClientMessage next = current;
            current = null;
            msg = HornetQMessage.createMessage(next, session);
            try
            {
               msg.doBeforeReceive();
            }
            catch (Exception e)
            {
               HornetQJMSClientLogger.LOGGER.errorCreatingMessage(e);

               return null;
            }
            return msg;
         }
         else
         {
            throw new NoSuchElementException();
         }
      }
   }
}