javax.jms: public interface: MessageConsumer

javax.jms
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.

Also see:

javax.jms.QueueReceiver

javax.jms.TopicSubscriber

javax.jms.Session

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.