com.solacesystems.jms

Class SolConnectionConsumer

java.lang.Object

com.solacesystems.jms.SolConnectionConsumer

All Implemented Interfaces:

SolCloseableIF, SolConnectionConsumerIF, SolStartableIF, ConnectionConsumer

public class SolConnectionConsumer
extends Object
implements SolConnectionConsumerIF

A specialized facility for application servers. The ConnectionConsumer gets a ServerSession and loads messages to it. Exceptions are dispatched to the connection for processing by its Exception listener.

Commit modes and transaction considerations

The JCSMP consumer used internally must have configuration data. On startup, we poll a single ServerSession from the ServerSessionPool, and sniff its configuration to configure our underlying JCSMP flow. This implementation relies on a few different strategies for ack and transaction support:

     +---------------------------------------------------------------------------------+
     |ackMode                  Destination   ConnectionConsumerTransactionStrategy     |
     +---------------------------------------------------------------------------------+
     |AUTO_ACKNOWLEDGE                                                                 |
     |CLIENT_ACKNOWLEDGE       *             ConnectionConsumerNoTransactionStrategy   |
     |DUPS_OK_ACKNOWLEDGE                                                              |
     +---------------------------------------------------------------------------------+
     |SESSION_TRANSACTED       Durable       ConnectionConsumerFakeTransactionStrategy |
     |                         Non-Durable   ConnectionConsumerLocalTxStrategy         |
     +---------------------------------------------------------------------------------+
 

In non-transacted acknowledgement modes, the 'NoTransactionStrategy' is used, which lets the app or container simply control calling Message.acknowledge() normally.

In transacted mode, for durable endpoints, we fake transactions for higher performance. We leave messages unacked to the appliance, and ack the batch of messages associated with a session when that session's commit() is called. When a rollback() is requested, we stop polling new messages, and wait (up to 5s) for any outstanding messages already given to the ServerSessionPool to be acked or rolledback. Then, we destroy the flow and recreate it, causing redelivery of every unacked message.

In transacted mode, for non-durable endpoints, the above approach doesn't work because the endpoint would be deleted when closing the first flow, and they are exclusive so we cannot open a second flow before closing the first. We therefore use an actual transacted-session with the appliance, within which the consumer flow is contained. This is much slower because to demarcate transactions, we must have only ONE active at a time. In this mode, a single message batch is read from the flow, handed off to a ServerSession, and we block until its commit() or rollback() is called. Once the commit/rollback occurs, we unblock and call commit/rollback on the underlying JCSMP transaction, then return to polling for more messages.

Constructor Summary

Constructors

Constructor and Description
SolConnectionConsumer(SolConnectionIF conn, SolDestinationInfo destInfo, String messageSelector, ServerSessionPool serverPool, int maxMessages, JMSState state)

Method Summary

Modifier and Type	Method and Description
void	close() Closes the connection consumer.
void	commitBatch(Collection<Message> msgs)
ServerSessionPool	getServerSessionPool() Gets the server session pool associated with this connection consumer.
void	rollbackBatch(Collection<Message> msgs)
void	start()
void	stop()
String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

SolConnectionConsumer

public SolConnectionConsumer(SolConnectionIF conn,
                             SolDestinationInfo destInfo,
                             String messageSelector,
                             ServerSessionPool serverPool,
                             int maxMessages,
                             JMSState state)
                      throws JMSException

Throws:

JMSException

Method Detail

getServerSessionPool

public ServerSessionPool getServerSessionPool()
                                       throws JMSException

Description copied from interface: ConnectionConsumer

Gets the server session pool associated with this connection consumer.

Specified by:

getServerSessionPool in interface ConnectionConsumer

Returns:

the server session pool used by this connection consumer

Throws:

JMSException - if the JMS provider fails to get the server session pool associated with this consumer due to some internal error.

start

public void start()
           throws JMSException

Specified by:

start in interface SolStartableIF

Throws:

JMSException

stop

public void stop()
          throws JMSException

Specified by:

stop in interface SolStartableIF

Throws:

JMSException

close

public void close()
           throws JMSException

Description copied from interface: ConnectionConsumer

Closes the connection consumer.

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

Specified by:

close in interface SolCloseableIF

Specified by:

close in interface ConnectionConsumer

Throws:

JMSException - if the JMS provider fails to release resources on behalf of the connection consumer or fails to close the connection consumer.

toString

public String toString()

Overrides:

toString in class Object

commitBatch

public void commitBatch(Collection<Message> msgs)
                 throws JMSException

Specified by:

commitBatch in interface SolConnectionConsumerIF

Throws:

JMSException

rollbackBatch

public void rollbackBatch(Collection<Message> msgs)
                   throws JMSException

Specified by:

rollbackBatch in interface SolConnectionConsumerIF

Throws:

JMSException