Class EsbConnectionManager

java.lang.Object

com.kingsrook.qqq.esb.connection.EsbConnectionManager

public final class EsbConnectionManager
extends Object

Long-lived JMS connections to ESB providers (brokers): one connection per provider, shared by every session opened on it. A provider's connection is made, from the provider's meta-data in the QContext's instance, on the first openSession for that provider, and is kept until closeAll. Each openSession call opens a new session on it; callers close the sessions they open. Publishing uses a separate bounded pool of exclusive transacted leases, invalidated whenever the connection is lost. Connecting waits at most EsbConnectionFactoryBuilder.CONNECT_TIMEOUT_MS (5 s). When a connection can't be made, or is lost (reported to the JMS ExceptionListener), the manager reconnects in the background with backoff (1 s, doubling up to 30 s), then fires the provider's connection listeners, so the owners of sessions and consumers (which died with the old connection) can open new ones. While it is reconnecting, openSession fails at once rather than waiting - so a broker that is down holds up only the first attempt (by at most the connect timeout), not every one after it.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	EsbConnectionManager.PublishingSessionLease	One exclusive publication.

Method Summary

Modifier and Type	Method	Description
void	addConnectionListener(String providerName, Runnable onReconnect)	Add a listener to run each time the manager (re)connects to the provider in the background - after a lost connection, or after a first connect that failed.
EsbConnectionManager.PublishingSessionLease	borrowPublishingSession(String providerName)	Exclusively borrow a transacted publishing session.
void	closeAll()	Close every provider's connection (and so every session on them), stop any background reconnecting, and remove all connection listeners - a full reset.
static EsbConnectionManager	getInstance()	Get the singleton instance.
boolean	isConnected(String providerName)	Whether the provider has a live connection (false if it was never connected, or is reconnecting).
jakarta.jms.Session	openSession(String providerName, boolean transacted)	Open a new session on a provider's connection - connecting first, if this is the provider's first session.
jakarta.jms.Destination	resolve(jakarta.jms.Session session, QEsbDestinationMetaData destination)	The JMS Queue or Topic for an ESB destination, on a session from openSession for the destination's provider.
jakarta.jms.Queue	resolveQueue(jakarta.jms.Session session, String providerName, String brokerQueueName)	The JMS Queue for a broker-side queue name (e.g., a dead-letter queue), on a session from openSession for the provider.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

getInstance

public static EsbConnectionManager getInstance()

Get the singleton instance.

openSession

public jakarta.jms.Session openSession(String providerName,
 boolean transacted)
                                throws QException

Open a new session on a provider's connection - connecting first, if this is the provider's first session. A transacted session sends and receives when it commits; a non-transacted one auto-acknowledges. Throws QException if the provider is unknown, its broker client isn't on the classpath, or it can't be connected to (then the manager keeps trying in the background - see the class comment).

Throws:

QException

borrowPublishingSession

public EsbConnectionManager.PublishingSessionLease borrowPublishingSession(String providerName)
                                                                    throws QException

Exclusively borrow a transacted publishing session. Capacity is bounded per provider; healthy saturation waits interruptibly for a returned lease. Close the producer before committing the lease. Closing an uncommitted lease rolls back and discards it. Consumer openSession ownership is separate.

Throws:

QException

resolve

public jakarta.jms.Destination resolve(jakarta.jms.Session session,
 QEsbDestinationMetaData destination)
                                throws jakarta.jms.JMSException

The JMS Queue or Topic for an ESB destination, on a session from openSession for the destination's provider.

Throws:

jakarta.jms.JMSException

resolveQueue

public jakarta.jms.Queue resolveQueue(jakarta.jms.Session session,
 String providerName,
 String brokerQueueName)
                               throws jakarta.jms.JMSException

The JMS Queue for a broker-side queue name (e.g., a dead-letter queue), on a session from openSession for the provider.

Throws:

jakarta.jms.JMSException

isConnected

public boolean isConnected(String providerName)

Whether the provider has a live connection (false if it was never connected, or is reconnecting).

addConnectionListener

public void addConnectionListener(String providerName,
 Runnable onReconnect)

Add a listener to run each time the manager (re)connects to the provider in the background - after a lost connection, or after a first connect that failed. Listeners run on the reconnecting thread (which has no QContext); one that throws is logged, and doesn't stop the others.

closeAll

public void closeAll()

Close every provider's connection (and so every session on them), stop any background reconnecting, and remove all connection listeners - a full reset. The next openSession connects anew.