001    /** 
002     * 
003     * Copyright 2004 Protique Ltd
004     * 
005     * Licensed under the Apache License, Version 2.0 (the "License"); 
006     * you may not use this file except in compliance with the License. 
007     * You may obtain a copy of the License at 
008     * 
009     * http://www.apache.org/licenses/LICENSE-2.0
010     * 
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS, 
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
014     * See the License for the specific language governing permissions and 
015     * limitations under the License. 
016     * 
017     **/
018    
019    package org.activemq;
020    
021    import org.activemq.message.ActiveMQDestination;
022    
023    import javax.jms.JMSException;
024    import javax.jms.Queue;
025    import javax.jms.QueueReceiver;
026    
027    /**
028     * A client uses a <CODE>QueueReceiver</CODE> object to receive messages that
029     * have been delivered to a queue.
030     * <p/>
031     * <P>
032     * Although it is possible to have multiple <CODE>QueueReceiver</CODE> s for
033     * the same queue, the JMS API does not define how messages are distributed
034     * between the <CODE>QueueReceiver</CODE>s.
035     * <p/>
036     * <P>
037     * If a <CODE>QueueReceiver</CODE> specifies a message selector, the messages
038     * that are not selected remain on the queue. By definition, a message selector
039     * allows a <CODE>QueueReceiver</CODE> to skip messages. This means that when
040     * the skipped messages are eventually read, the total ordering of the reads
041     * does not retain the partial order defined by each message producer. Only
042     * <CODE>QueueReceiver</CODE> s without a message selector will read messages
043     * in message producer order.
044     * <p/>
045     * <P>
046     * Creating a <CODE>MessageConsumer</CODE> provides the same features as
047     * creating a <CODE>QueueReceiver</CODE>. A <CODE>MessageConsumer</CODE>
048     * object is recommended for creating new code. The <CODE>QueueReceiver
049     * </CODE> is provided to support existing code.
050     *
051     * @see javax.jms.Session#createConsumer(javax.jms.Destination, String)
052     * @see javax.jms.Session#createConsumer(javax.jms.Destination)
053     * @see javax.jms.QueueSession#createReceiver(Queue, String)
054     * @see javax.jms.QueueSession#createReceiver(Queue)
055     * @see javax.jms.MessageConsumer
056     */
057    
058    public class ActiveMQQueueReceiver extends ActiveMQMessageConsumer implements
059            QueueReceiver {
060    
061        /**
062         * @param theSession
063         * @param dest
064         * @param selector
065         * @param cnum
066         * @param prefetch
067         * @throws JMSException
068         */
069        protected ActiveMQQueueReceiver(ActiveMQSession theSession,
070                                        ActiveMQDestination dest, String selector, int cnum, int prefetch)
071                throws JMSException {
072            super(theSession, dest, "", selector, cnum, prefetch, false, false);
073        }
074    
075        /**
076         * Gets the <CODE>Queue</CODE> associated with this queue receiver.
077         *
078         * @return this receiver's <CODE>Queue</CODE>
079         * @throws JMSException if the JMS provider fails to get the queue for this queue
080         *                      receiver due to some internal error.
081         */
082    
083        public Queue getQueue() throws JMSException {
084            checkClosed();
085            return (Queue) super.getDestination();
086        }
087    }