ActiveMQQueueReceiver xref

View Javadoc

    1   /***
    2    *
    3    * Copyright 2004 Protique Ltd
    4    *
    5    * Licensed under the Apache License, Version 2.0 (the "License");
    6    * you may not use this file except in compliance with the License.
    7    * You may obtain a copy of the License at
    8    *
    9    * http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   **/
    18
    19  package org.codehaus.activemq;
    20
    21  import org.codehaus.activemq.message.ActiveMQDestination;
    22
    23  import javax.jms.JMSException;
    24  import javax.jms.Queue;
    25  import javax.jms.QueueReceiver;
    26
    27  /***
    28   * A client uses a <CODE>QueueReceiver</CODE> object to receive messages that
    29   * have been delivered to a queue.
    30   * <p/>
    31   * <P>
    32   * Although it is possible to have multiple <CODE>QueueReceiver</CODE> s for
    33   * the same queue, the JMS API does not define how messages are distributed
    34   * between the <CODE>QueueReceiver</CODE>s.
    35   * <p/>
    36   * <P>
    37   * If a <CODE>QueueReceiver</CODE> specifies a message selector, the messages
    38   * that are not selected remain on the queue. By definition, a message selector
    39   * allows a <CODE>QueueReceiver</CODE> to skip messages. This means that when
    40   * the skipped messages are eventually read, the total ordering of the reads
    41   * does not retain the partial order defined by each message producer. Only
    42   * <CODE>QueueReceiver</CODE> s without a message selector will read messages
    43   * in message producer order.
    44   * <p/>
    45   * <P>
    46   * Creating a <CODE>MessageConsumer</CODE> provides the same features as
    47   * creating a <CODE>QueueReceiver</CODE>. A <CODE>MessageConsumer</CODE>
    48   * object is recommended for creating new code. The <CODE>QueueReceiver
    49   * </CODE> is provided to support existing code.
    50   *
    51   * @see javax.jms.Session#createConsumer(javax.jms.Destination, String)
    52   * @see javax.jms.Session#createConsumer(javax.jms.Destination)
    53   * @see javax.jms.QueueSession#createReceiver(Queue, String)
    54   * @see javax.jms.QueueSession#createReceiver(Queue)
    55   * @see javax.jms.MessageConsumer
    56   */
    57
    58  public class ActiveMQQueueReceiver extends ActiveMQMessageConsumer implements
    59          QueueReceiver {
    60
    61      /***
    62       * @param theSession
    63       * @param dest
    64       * @param selector
    65       * @param cnum
    66       * @param prefetch
    67       * @throws JMSException
    68       */
    69      protected ActiveMQQueueReceiver(ActiveMQSession theSession,
    70                                      ActiveMQDestination dest, String selector, int cnum, int prefetch)
    71              throws JMSException {
    72          super(theSession, dest, "", selector, cnum, prefetch, false, false);
    73      }
    74
    75      /***
    76       * Gets the <CODE>Queue</CODE> associated with this queue receiver.
    77       *
    78       * @return this receiver's <CODE>Queue</CODE>
    79       * @throws JMSException if the JMS provider fails to get the queue for this queue
    80       *                      receiver due to some internal error.
    81       */
    82
    83      public Queue getQueue() throws JMSException {
    84          checkClosed();
    85          return (Queue) super.getDestination();
    86      }
    87  }