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public interface: MessageConsumer [javadoc | source]

All Known Implementing Classes:
    QueueReceiver, TopicSubscriber

A client uses a MessageConsumer object to receive messages from a destination. A MessageConsumer object is created by passing a Destination object to a message-consumer creation method supplied by a session.

MessageConsumer is the parent interface for all message consumers.

A message consumer can be created with a message selector. A message selector allows the client to restrict the messages delivered to the message consumer to those that match the selector.

A client may either synchronously receive a message consumer's messages or have the consumer asynchronously deliver them as they arrive.

For synchronous receipt, a client can request the next message from a message consumer using one of its receive methods. There are several variations of receive that allow a client to poll or wait for the next message.

For asynchronous delivery, a client can register a MessageListener object with a message consumer. As messages arrive at the message consumer, it delivers them by calling the MessageListener's onMessage method.

It is a client programming error for a MessageListener to throw an exception.

Method from javax.jms.MessageConsumer Summary:
close,   getMessageListener,   getMessageSelector,   receive,   receive,   receiveNoWait,   setMessageListener
Method from javax.jms.MessageConsumer Detail:
 public  void close() throws JMSException
    Closes the message consumer.

    Since a provider may allocate some resources on behalf of a MessageConsumer outside the Java virtual machine, clients should close them when they are not needed. Relying on garbage collection to eventually reclaim these resources may not be timely enough.

    This call blocks until a receive or message listener in progress has completed. A blocked message consumer receive call returns null when this message consumer is closed.

 public MessageListener getMessageListener() throws JMSException
    Gets the message consumer's MessageListener.
 public String getMessageSelector() throws JMSException
    Gets this message consumer's message selector expression.
 public Message receive() throws JMSException
    Receives the next message produced for this message consumer.

    This call blocks indefinitely until a message is produced or until this message consumer is closed.

    If this receive is done within a transaction, the consumer retains the message until the transaction commits.

 public Message receive(long timeout) throws JMSException
    Receives the next message that arrives within the specified timeout interval.

    This call blocks until a message arrives, the timeout expires, or this message consumer is closed. A timeout of zero never expires, and the call blocks indefinitely.

 public Message receiveNoWait() throws JMSException
    Receives the next message if one is immediately available.
 public  void setMessageListener(MessageListener listener) throws JMSException
    Sets the message consumer's MessageListener.

    Setting the message listener to null is the equivalent of unsetting the message listener for the message consumer.

    The effect of calling MessageConsumer.setMessageListener while messages are being consumed by an existing listener or the consumer is being used to consume messages synchronously is undefined.