Module jakarta.messaging

Package jakarta.jms

Interface QueueConnection

All Superinterfaces:

AutoCloseable, Connection

All Known Subinterfaces:

XAQueueConnection

public interface QueueConnection
extends Connection

A QueueConnection object is an active connection to a point-to-point Jakarta Messaging provider. A client uses a QueueConnection object to create one or more QueueSession objects for producing and consuming messages.

A QueueConnection can be used to create a QueueSession, from which specialized queue-related objects can be created. A more general, and recommended, approach is to use the Connection object.

The QueueConnection object should be used to support existing code that has already used it.

A QueueConnection cannot be used to create objects specific to the publish/subscribe domain. The createDurableConnectionConsumer method inherits from Connection, but must throw an IllegalStateException if used from QueueConnection.

Since:

JMS 1.0

Version:

Jakarta Messaging 2.0

See Also:

• Connection
• ConnectionFactory
• QueueConnectionFactory

Method Summary

Modifier and Type	Method	Description
ConnectionConsumer	createConnectionConsumer(Queue queue, String messageSelector, ServerSessionPool sessionPool, int maxMessages)	Creates a connection consumer for this connection (optional operation).
QueueSession	createQueueSession(boolean transacted, int acknowledgeMode)	Creates a QueueSession object, specifying transacted and acknowledgeMode.

Methods inherited from interface jakarta.jms.Connection

close, createConnectionConsumer, createDurableConnectionConsumer, createSession, createSession, createSession, createSharedConnectionConsumer, createSharedDurableConnectionConsumer, getClientID, getExceptionListener, getMetaData, setClientID, setExceptionListener, start, stop

Method Details

createQueueSession

QueueSession createQueueSession(boolean transacted,
 int acknowledgeMode)
                         throws JMSException

Creates a QueueSession object, specifying transacted and acknowledgeMode.

The effect of setting the transacted and acknowledgeMode arguments depends on whether this method is called in a Java SE environment, in the Jakarta EE application client container, or in the Jakarta EE web or EJB container. If this method is called in the Jakarta EE web or EJB container then the effect of setting the transacted} and acknowledgeMode arguments also depends on whether or not there is an active JTA transaction in progress.

In a Java SE environment or in the Jakarta EE application client container:

• If transacted is set to true then the session will use a local transaction which may subsequently be committed or rolled back by calling the session's commit or rollback methods. The argument acknowledgeMode is ignored.
• If transacted is set to false then the session will be non-transacted. In this case the argument acknowledgeMode is used to specify how messages received by this session will be acknowledged. The permitted values are Session.CLIENT_ACKNOWLEDGE, Session.AUTO_ACKNOWLEDGE and Session.DUPS_OK_ACKNOWLEDGE. For a definition of the meaning of these acknowledgement modes see the links below.

In a Jakarta EE web or EJB container, when there is an active JTA transaction in progress:

• Both arguments transacted and acknowledgeMode are ignored. The session will participate in the JTA transaction and will be committed or rolled back when that transaction is committed or rolled back, not by calling the session's commit or rollback methods. Since both arguments are ignored, developers are recommended to use createSession(), which has no arguments, instead of this method.

In the Jakarta EE web or EJB container, when there is no active JTA transaction in progress:

• If transacted is set to false and acknowledgeMode is set to JMSContext.AUTO_ACKNOWLEDGE or Session.DUPS_OK_ACKNOWLEDGE then the session will be non-transacted and messages will be acknowledged according to the value of acknowledgeMode.
• If transacted is set to false and acknowledgeMode is set to JMSContext.CLIENT_ACKNOWLEDGE then the Jakarta Messaging provider is recommended to ignore the specified parameters and instead provide a non-transacted, auto-acknowledged session. However the Jakarta Messaging provider may alternatively provide a non-transacted session with client acknowledgement.
• If transacted is set to true, then the Jakarta Messaging provider is recommended to ignore the specified parameters and instead provide a non-transacted, auto-acknowledged session. However the Jakarta Messaging provider may alternatively provide a local transacted session.
• Applications are recommended to set transacted to false and acknowledgeMode to JMSContext.AUTO_ACKNOWLEDGE or Session.DUPS_OK_ACKNOWLEDGE since since applications which set transacted to false and set acknowledgeMode to JMSContext.CLIENT_ACKNOWLEDGE, or which set transacted to true, may not be portable.

Applications running in the Jakarta EE web and EJB containers must not attempt to create more than one active (not closed) Session object per connection. If this method is called in a Jakarta EE web or EJB container when an active Session object already exists for this connection then a JMSException may be thrown.

Parameters:

transacted - indicates whether the session will use a local transaction, except in the cases described above when this value is ignored.

acknowledgeMode - when transacted is false, indicates how messages received by the session will be acknowledged, except in the cases described above when this value is ignored.

Returns:

a newly created QueueSession

Throws:

JMSException - if the QueueConnection object fails to create a QueueSession due to

• some internal error,
• lack of support for the specific transaction and acknowledgement mode, or
• because this method is being called in a Jakarta EE web or EJB application and an active session already exists for this connection.

Since:

JMS 1.1

See Also:

• Session.AUTO_ACKNOWLEDGE
• Session.CLIENT_ACKNOWLEDGE
• Session.DUPS_OK_ACKNOWLEDGE

createConnectionConsumer

ConnectionConsumer createConnectionConsumer(Queue queue,
 String messageSelector,
 ServerSessionPool sessionPool,
 int maxMessages)
                                     throws JMSException

Creates a connection consumer for this connection (optional operation). This is an expert facility not used by regular Jakarta Messaging clients.

Parameters:

queue - the queue to access

messageSelector - only messages with properties matching the message selector expression are delivered. A value of null or an empty string indicates that there is no message selector for the message consumer.

sessionPool - the server session pool to associate with this connection consumer

maxMessages - the maximum number of messages that can be assigned to a server session at one time

Returns:

the connection consumer

Throws:

JMSException - if the QueueConnection object fails to create a connection consumer due to some internal error or invalid arguments for sessionPool and messageSelector.

InvalidDestinationException - if an invalid queue is specified.

InvalidSelectorException - if the message selector is invalid.

See Also:

• ConnectionConsumer