Module jakarta.messaging

Package jakarta.jms

Interface Session

All Superinterfaces:

AutoCloseable, Runnable

All Known Subinterfaces:

QueueSession, TopicSession, XAQueueSession, XASession, XATopicSession

public interface Session
extends Runnable, AutoCloseable

A Session object is a single-threaded context for producing and consuming messages. Although it may allocate provider resources outside the Java virtual machine (JVM), it is considered a lightweight Jakarta Messaging object.

A session serves several purposes:

• It is a factory for its message producers and consumers.
• It supplies provider-optimized message factories.
• It is a factory for TemporaryTopics and TemporaryQueues.
• It provides a way to create Queue or Topic objects for those clients that need to dynamically manipulate provider-specific destination names.
• It supports a single series of transactions that combine work spanning its producers and consumers into atomic units.
• It defines a serial order for the messages it consumes and the messages it produces.
• It retains messages it consumes until they have been acknowledged.
• It serializes execution of message listeners registered with its message consumers.
• It is a factory for QueueBrowsers.

A session can create and service multiple message producers and consumers.

One typical use is to have a thread block on a synchronous MessageConsumer until a message arrives. The thread may then use one or more of the Session's MessageProducers.

If a client desires to have one thread produce messages while others consume them, the client should use a separate session for its producing thread.

Once a connection has been started, any session with one or more registered message listeners is dedicated to the thread of control that delivers messages to it. It is erroneous for client code to use this session or any of its constituent objects from another thread of control. The only exception to this rule is the use of the session or message consumer close method.

It should be easy for most clients to partition their work naturally into sessions. This model allows clients to start simply and incrementally add message processing complexity as their need for concurrency grows.

The close method is the only session method that can be called while some other session method is being executed in another thread.

A session may be specified as transacted. Each transacted session supports a single series of transactions. Each transaction groups a set of message sends and a set of message receives into an atomic unit of work. In effect, transactions organize a session's input message stream and output message stream into series of atomic units. When a transaction commits, its atomic unit of input is acknowledged and its associated atomic unit of output is sent. If a transaction rollback is done, the transaction's sent messages are destroyed and the session's input is automatically recovered.

The content of a transaction's input and output units is simply those messages that have been produced and consumed within the session's current transaction.

A transaction is completed using either its session's commit method or its session's rollback method. The completion of a session's current transaction automatically begins the next. The result is that a transacted session always has a current transaction within which its work is done.

The Java Transaction Service (JTS) or some other transaction monitor may be used to combine a session's transaction with transactions on other resources (databases, other Jakarta Messaging sessions, etc.). Since Java distributed transactions are controlled via the Java Transaction API (JTA), use of the session's commit and rollback methods in this context is prohibited.

The Jakarta Messaging API does not require support for JTA; however, it does define how a provider supplies this support.

Although it is also possible for a Jakarta Messaging client to handle distributed transactions directly, it is unlikely that many Jakarta Messaging clients will do this. Support for JTA in the Jakarta Messaging API is targeted at systems vendors who will be integrating the Jakarta Messaging API into their application server products.

Since:

JMS 1.0

Version:

Jakarta Messaging 2.0

See Also:

• QueueSession
• TopicSession
• XASession

Field Summary

Fields

Modifier and Type	Field	Description
static final int	AUTO_ACKNOWLEDGE	With this acknowledgment mode, the session automatically acknowledges a client's receipt of a message either when the session has successfully returned from a call to receive or when the message listener the session has called to process the message successfully returns.
static final int	CLIENT_ACKNOWLEDGE	With this acknowledgment mode, the client acknowledges a consumed message by calling the message's acknowledge method.
static final int	DUPS_OK_ACKNOWLEDGE	This acknowledgment mode instructs the session to lazily acknowledge the delivery of messages.
static final int	SESSION_TRANSACTED	This value may be passed as the argument to the method createSession(int sessionMode) on the Connection object to specify that the session should use a local transaction.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the session.
void	commit()	Commits all messages done in this transaction and releases any locks currently held.
QueueBrowser	createBrowser(Queue queue)	Creates a QueueBrowser object to peek at the messages on the specified queue.
QueueBrowser	createBrowser(Queue queue, String messageSelector)	Creates a QueueBrowser object to peek at the messages on the specified queue using a message selector.
BytesMessage	createBytesMessage()	Creates a BytesMessage object.
MessageConsumer	createConsumer(Destination destination)	Creates a MessageConsumer for the specified destination.
MessageConsumer	createConsumer(Destination destination, String messageSelector)	Creates a MessageConsumer for the specified destination, using a message selector.
MessageConsumer	createConsumer(Destination destination, String messageSelector, boolean noLocal)	Creates a MessageConsumer for the specified destination, specifying a message selector and the noLocal parameter.
MessageConsumer	createDurableConsumer(Topic topic, String name)	Creates an unshared durable subscription on the specified topic (if one does not already exist) and creates a consumer on that durable subscription.
MessageConsumer	createDurableConsumer(Topic topic, String name, String messageSelector, boolean noLocal)	Creates an unshared durable subscription on the specified topic (if one does not already exist), specifying a message selector and the noLocal parameter, and creates a consumer on that durable subscription.
TopicSubscriber	createDurableSubscriber(Topic topic, String name)	Creates an unshared durable subscription on the specified topic (if one does not already exist) and creates a consumer on that durable subscription.
TopicSubscriber	createDurableSubscriber(Topic topic, String name, String messageSelector, boolean noLocal)	Creates an unshared durable subscription on the specified topic (if one does not already exist), specifying a message selector and the noLocal parameter, and creates a consumer on that durable subscription.
MapMessage	createMapMessage()	Creates a MapMessage object.
Message	createMessage()	Creates a Message object.
ObjectMessage	createObjectMessage()	Creates an ObjectMessage object.
ObjectMessage	createObjectMessage(Serializable object)	Creates an initialized ObjectMessage object.
MessageProducer	createProducer(Destination destination)	Creates a MessageProducer to send messages to the specified destination.
Queue	createQueue(String queueName)	Creates a Queue object which encapsulates a specified provider-specific queue name.
MessageConsumer	createSharedConsumer(Topic topic, String sharedSubscriptionName)	Creates a shared non-durable subscription with the specified name on the specified topic (if one does not already exist) and creates a consumer on that subscription.
MessageConsumer	createSharedConsumer(Topic topic, String sharedSubscriptionName, String messageSelector)	Creates a shared non-durable subscription with the specified name on the specified topic (if one does not already exist) specifying a message selector, and creates a consumer on that subscription.
MessageConsumer	createSharedDurableConsumer(Topic topic, String name)	Creates a shared durable subscription on the specified topic (if one does not already exist), specifying a message selector and the noLocal parameter, and creates a consumer on that durable subscription.
MessageConsumer	createSharedDurableConsumer(Topic topic, String name, String messageSelector)	Creates a shared durable subscription on the specified topic (if one does not already exist), specifying a message selector, and creates a consumer on that durable subscription.
StreamMessage	createStreamMessage()	Creates a StreamMessage object.
TemporaryQueue	createTemporaryQueue()	Creates a TemporaryQueue object.
TemporaryTopic	createTemporaryTopic()	Creates a TemporaryTopic object.
TextMessage	createTextMessage()	Creates a TextMessage object.
TextMessage	createTextMessage(String text)	Creates an initialized TextMessage object.
Topic	createTopic(String topicName)	Creates a Topic object which encapsulates a specified provider-specific topic name.
int	getAcknowledgeMode()	Returns the acknowledgement mode of the session.
MessageListener	getMessageListener()	Returns the session's distinguished message listener (optional).
boolean	getTransacted()	Indicates whether the session is in transacted mode.
void	recover()	Stops message delivery in this session, and restarts message delivery with the oldest unacknowledged message.
void	rollback()	Rolls back any messages done in this transaction and releases any locks currently held.
void	run()	Optional operation, intended to be used only by Application Servers, not by ordinary Jakarta Messaging clients.
void	setMessageListener(MessageListener listener)	Sets the session's distinguished message listener (optional).
void	unsubscribe(String name)	Unsubscribes a durable subscription that has been created by a client.

Field Details

AUTO_ACKNOWLEDGE

static final int AUTO_ACKNOWLEDGE

With this acknowledgment mode, the session automatically acknowledges a client's receipt of a message either when the session has successfully returned from a call to receive or when the message listener the session has called to process the message successfully returns.

See Also:

• Constant Field Values

CLIENT_ACKNOWLEDGE

static final int CLIENT_ACKNOWLEDGE

With this acknowledgment mode, the client acknowledges a consumed message by calling the message's acknowledge method. Acknowledging a consumed message acknowledges all messages that the session has consumed.

When client acknowledgment mode is used, a client may build up a large number of unacknowledged messages while attempting to process them. A Jakarta Messaging provider should provide administrators with a way to limit client overrun so that clients are not driven to resource exhaustion and ensuing failure when some resource they are using is temporarily blocked.

See Also:

• Message.acknowledge()
• Constant Field Values

DUPS_OK_ACKNOWLEDGE

static final int DUPS_OK_ACKNOWLEDGE

This acknowledgment mode instructs the session to lazily acknowledge the delivery of messages. This is likely to result in the delivery of some duplicate messages if the Jakarta Messaging provider fails, so it should only be used by consumers that can tolerate duplicate messages. Use of this mode can reduce session overhead by minimizing the work the session does to prevent duplicates.

See Also:

• Constant Field Values

SESSION_TRANSACTED

static final int SESSION_TRANSACTED

This value may be passed as the argument to the method createSession(int sessionMode) on the Connection object to specify that the session should use a local transaction.

This value is returned from the method getAcknowledgeMode if the session is using a local transaction, irrespective of whether the session was created by calling the method createSession(int sessionMode) or the method createSession(boolean transacted, int acknowledgeMode).

Since:

JMS 1.1

See Also:

• Constant Field Values

Method Details

createBytesMessage

BytesMessage createBytesMessage()
                         throws JMSException

Creates a BytesMessage object. A BytesMessage object is used to send a message containing a stream of uninterpreted bytes.

The message object returned may be sent using any Session or JMSContext. It is not restricted to being sent using the JMSContext used to create it.

The message object returned may be optimised for use with the Jakarta Messaging provider used to create it. However it can be sent using any Jakarta Messaging provider, not just the Jakarta Messaging provider used to create it.

Returns:

A BytesMessage object.

Throws:

JMSException - if the Jakarta Messaging provider fails to create this message due to some internal error.

createMapMessage

MapMessage createMapMessage()
                     throws JMSException

Creates a MapMessage object. A MapMessage object is used to send a self-defining set of name-value pairs, where names are String objects and values are primitive values in the Java programming language.

The message object returned may be sent using any Session or JMSContext. It is not restricted to being sent using the JMSContext used to create it.

The message object returned may be optimised for use with the Jakarta Messaging provider used to create it. However it can be sent using any Jakarta Messaging provider, not just the Jakarta Messaging provider used to create it.

Returns:

A MapMessage object.

Throws:

JMSException - if the Jakarta Messaging provider fails to create this message due to some internal error.

createMessage

Message createMessage()
               throws JMSException

Creates a Message object. The Message interface is the root interface of all Jakarta Messaging messages. A Message object holds all the standard message header information. It can be sent when a message containing only header information is sufficient.

The message object returned may be sent using any Session or JMSContext. It is not restricted to being sent using the JMSContext used to create it.

The message object returned may be optimised for use with the Jakarta Messaging provider used to create it. However it can be sent using any Jakarta Messaging provider, not just the Jakarta Messaging provider used to create it.

Returns:

A Message object.

Throws:

JMSException - if the Jakarta Messaging provider fails to create this message due to some internal error.

createObjectMessage

ObjectMessage createObjectMessage()
                           throws JMSException

Creates an ObjectMessage object. An ObjectMessage object is used to send a message that contains a serializable Java object.

The message object returned may be sent using any Session or JMSContext. It is not restricted to being sent using the JMSContext used to create it.

The message object returned may be optimised for use with the Jakarta Messaging provider used to create it. However it can be sent using any Jakarta Messaging provider, not just the Jakarta Messaging provider used to create it.

Returns:

A ObjectMessage object.

Throws:

JMSException - if the Jakarta Messaging provider fails to create this message due to some internal error.

createObjectMessage

ObjectMessage createObjectMessage(Serializable object)
                           throws JMSException

Creates an initialized ObjectMessage object. An ObjectMessage object is used to send a message that contains a serializable Java object.

The message object returned may be sent using any Session or JMSContext. It is not restricted to being sent using the JMSContext used to create it.

The message object returned may be optimised for use with the Jakarta Messaging provider used to create it. However it can be sent using any Jakarta Messaging provider, not just the Jakarta Messaging provider used to create it.

Parameters:

object - the object to use to initialize this message

Returns:

A ObjectMessage object.

Throws:

JMSException - if the Jakarta Messaging provider fails to create this message due to some internal error.

createStreamMessage

StreamMessage createStreamMessage()
                           throws JMSException

Creates a StreamMessage object. A StreamMessage object is used to send a self-defining stream of primitive values in the Java programming language.

The message object returned may be sent using any Session or JMSContext. It is not restricted to being sent using the JMSContext used to create it.

The message object returned may be optimised for use with the Jakarta Messaging provider used to create it. However it can be sent using any Jakarta Messaging provider, not just the Jakarta Messaging provider used to create it.

Returns:

A StreamMessage object.

Throws:

JMSException - if the Jakarta Messaging provider fails to create this message due to some internal error.

createTextMessage

TextMessage createTextMessage()
                       throws JMSException

Creates a TextMessage object. A TextMessage object is used to send a message containing a String object.

The message object returned may be sent using any Session or JMSContext. It is not restricted to being sent using the JMSContext used to create it.

The message object returned may be optimised for use with the Jakarta Messaging provider used to create it. However it can be sent using any Jakarta Messaging provider, not just the Jakarta Messaging provider used to create it.

Returns:

A TextMessage object.

Throws:

JMSException - if the Jakarta Messaging provider fails to create this message due to some internal error.

createTextMessage

TextMessage createTextMessage(String text)
                       throws JMSException

Creates an initialized TextMessage object. A TextMessage object is used to send a message containing a String.

The message object returned may be sent using any Session or JMSContext. It is not restricted to being sent using the JMSContext used to create it.

The message object returned may be optimised for use with the Jakarta Messaging provider used to create it. However it can be sent using any Jakarta Messaging provider, not just the Jakarta Messaging provider used to create it.

Parameters:

text - the string used to initialize this message

Returns:

A TextMessage object.

Throws:

JMSException - if the Jakarta Messaging provider fails to create this message due to some internal error.

getTransacted

boolean getTransacted()
               throws JMSException

Indicates whether the session is in transacted mode.

Returns:

true if the session is in transacted mode

Throws:

JMSException - if the Jakarta Messaging provider fails to return the transaction mode due to some internal error.

getAcknowledgeMode

int getAcknowledgeMode()
                throws JMSException

Returns the acknowledgement mode of the session. The acknowledgement mode is set at the time that the session is created. If the session is transacted, the acknowledgement mode is ignored.

Returns:

If the session is not transacted, returns the current acknowledgement mode for the session. If the session is transacted, returns SESSION_TRANSACTED.

Throws:

JMSException - if the Jakarta Messaging provider fails to return the acknowledgment mode due to some internal error.

Since:

JMS 1.1

See Also:

• Connection.createSession(boolean, int)

commit

void commit()
     throws JMSException

Commits all messages done in this transaction and releases any locks currently held.

This method must not return until any incomplete asynchronous send operations for this Session have been completed and any CompletionListener callbacks have returned. Incomplete sends should be allowed to complete normally unless an error occurs.

A CompletionListener callback method must not call commit on its own Session. Doing so will cause an IllegalStateException to be thrown.

Throws:

IllegalStateException -

• the session is not using a local transaction
• this method has been called by a CompletionListener callback method on its own Session

JMSException - if the Jakarta Messaging provider fails to commit the transaction due to some internal error.

TransactionRolledBackException - if the transaction is rolled back due to some internal error during commit.

rollback

void rollback()
       throws JMSException

Rolls back any messages done in this transaction and releases any locks currently held.

This method must not return until any incomplete asynchronous send operations for this Session have been completed and any CompletionListener callbacks have returned. Incomplete sends should be allowed to complete normally unless an error occurs.

A CompletionListener callback method must not call commit on its own Session. Doing so will cause an IllegalStateException to be thrown.

Throws:

IllegalStateException -

• the session is not using a local transaction
• this method has been called by a CompletionListener callback method on its own Session

JMSException - if the Jakarta Messaging provider fails to roll back the transaction due to some internal error.

close

void close()
    throws JMSException

Closes the session.

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

There is no need to close the producers and consumers of a closed session.

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

However if the close method is called from a message listener on its own Session, then it will either fail and throw a jakarta.jms.IllegalStateException, or it will succeed and close the Session, blocking until any pending receive call in progress has completed. If close succeeds and the acknowledge mode of the Session is set to AUTO_ACKNOWLEDGE, the current message will still be acknowledged automatically when the onMessage call completes.

Since two alternative behaviors are permitted in this case, applications should avoid calling close from a message listener on its own Session because this is not portable.

This method must not return until any incomplete asynchronous send operations for this Session have been completed and any CompletionListener callbacks have returned. Incomplete sends should be allowed to complete normally unless an error occurs.

For the avoidance of doubt, if an exception listener for this session's connection is running when close is invoked, there is no requirement for the close call to wait until the exception listener has returned before it may return.

Closing a transacted session must roll back the transaction in progress.

This method is the only Session method that can be called concurrently.

A CompletionListener callback method must not call close on its own Session. Doing so will cause an IllegalStateException to be thrown.

Invoking any other Session method on a closed session must throw a IllegalStateException. Closing a closed session must not throw an exception.

Specified by:

close in interface AutoCloseable

Throws:

IllegalStateException -

• this method has been called by a MessageListener on its own Session
• this method has been called by a CompletionListener callback method on its own Session

JMSException - if the Jakarta Messaging provider fails to close the session due to some internal error.

recover

void recover()
      throws JMSException

Stops message delivery in this session, and restarts message delivery with the oldest unacknowledged message.

All consumers deliver messages in a serial order. Acknowledging a received message automatically acknowledges all messages that have been delivered to the client.

Restarting a session causes it to take the following actions:

• Stop message delivery
• Mark all messages that might have been delivered but not acknowledged as "redelivered"
• Restart the delivery sequence including all unacknowledged messages that had been previously delivered. Redelivered messages do not have to be delivered in exactly their original delivery order.

Throws:

JMSException - if the Jakarta Messaging provider fails to stop and restart message delivery due to some internal error.

IllegalStateException - if the method is called by a transacted session.

getMessageListener

MessageListener getMessageListener()
                            throws JMSException

Returns the session's distinguished message listener (optional).

This method must not be used in a Jakarta EE web or EJB application. Doing so may cause a JMSException to be thrown though this is not guaranteed.

Returns:

the distinguished message listener associated with this session

Throws:

JMSException - if the Jakarta Messaging provider fails to get the session's distinguished message listener for one of the following reasons:

• an internal error has occurred
• this method has been called in a Jakarta EE web or EJB application (though it is not guaranteed that an exception is thrown in this case)

See Also:

• setMessageListener(jakarta.jms.MessageListener)
• ServerSessionPool
• ServerSession

setMessageListener

void setMessageListener(MessageListener listener)
                 throws JMSException

Sets the session's distinguished message listener (optional).

When the distinguished message listener is set, no other form of message receipt in the session can be used; however, all forms of sending messages are still supported.

This is an expert facility not used by ordinary Jakarta Messaging clients.

This method must not be used in a Jakarta EE web or EJB application. Doing so may cause a JMSException to be thrown though this is not guaranteed.

Parameters:

listener - the message listener to associate with this session

Throws:

JMSException - if the Jakarta Messaging provider fails to set the session's distinguished message listener for one of the following reasons:

• an internal error has occurred
• this method has been called in a Jakarta EE web or EJB application (though it is not guaranteed that an exception is thrown in this case)

See Also:

• getMessageListener()
• ServerSessionPool
• ServerSession

run

void run()

Optional operation, intended to be used only by Application Servers, not by ordinary Jakarta Messaging clients.

This method must not be used in a Jakarta EE web or EJB application. Doing so may cause a JMSRuntimeException to be thrown though this is not guaranteed.

Specified by:

run in interface Runnable

Throws:

JMSRuntimeException - if this method has been called in a Jakarta EE web or EJB application (though it is not guaranteed that an exception is thrown in this case)

See Also:

• ServerSession

createProducer

MessageProducer createProducer(Destination destination)
                        throws JMSException

Creates a MessageProducer to send messages to the specified destination.

A client uses a MessageProducer object to send messages to a destination. Since Queue and Topic both inherit from Destination, they can be used in the destination parameter to create a MessageProducer object.

Parameters:

destination - the Destination to send to, or null if this is a producer which does not have a specified destination.

Returns:

A MessageProducer to send messages.

Throws:

JMSException - if the session fails to create a MessageProducer due to some internal error.

InvalidDestinationException - if an invalid destination is specified.

Since:

JMS 1.1

createConsumer

MessageConsumer createConsumer(Destination destination)
                        throws JMSException

Creates a MessageConsumer for the specified destination. Since Queue and Topic both inherit from Destination, they can be used in the destination parameter to create a MessageConsumer.

Parameters:

destination - the Destination to access.

Returns:

A MessageConsumer for the specified destination.

Throws:

JMSException - if the session fails to create a consumer due to some internal error.

InvalidDestinationException - if an invalid destination is specified.

Since:

JMS 1.1

createConsumer

MessageConsumer createConsumer(Destination destination,
 String messageSelector)
                        throws JMSException

Creates a MessageConsumer for the specified destination, using a message selector. Since Queue and Topic both inherit from Destination, they can be used in the destination parameter to create a MessageConsumer.

A client uses a MessageConsumer object to receive messages that have been sent to a destination.

Parameters:

destination - the Destination 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.

Returns:

A MessageConsumer for the specified destination.

Throws:

JMSException - if the session fails to create a MessageConsumer due to some internal error.

InvalidDestinationException - if an invalid destination is specified.

InvalidSelectorException - if the message selector is invalid.

Since:

JMS 1.1

createConsumer

MessageConsumer createConsumer(Destination destination,
 String messageSelector,
 boolean noLocal)
                        throws JMSException

Creates a MessageConsumer for the specified destination, specifying a message selector and the noLocal parameter.

Since Queue and Topic both inherit from Destination, they can be used in the destination parameter to create a MessageConsumer.

A client uses a MessageConsumer object to receive messages that have been published to a destination.

The noLocal argument is for use when the destination is a topic and the session's connection is also being used to publish messages to that topic. If noLocal is set to true then the MessageConsumer will not receive messages published to the topic by its own connection. The default value of this argument is false. If the destination is a queue then the effect of setting noLocal to true is not specified.

Parameters:

destination - the Destination 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.

noLocal - - if true, and the destination is a topic, then the MessageConsumer will not receive messages published to the topic by its own connection.

Returns:

A MessageConsumer for the specified destination.

Throws:

JMSException - if the session fails to create a MessageConsumer due to some internal error.

InvalidDestinationException - if an invalid destination is specified.

InvalidSelectorException - if the message selector is invalid.

Since:

JMS 1.1

createSharedConsumer

MessageConsumer createSharedConsumer(Topic topic,
 String sharedSubscriptionName)
                              throws JMSException

Creates a shared non-durable subscription with the specified name on the specified topic (if one does not already exist) and creates a consumer on that subscription. This method creates the non-durable subscription without a message selector.

If a shared non-durable subscription already exists with the same name and client identifier (if set), and the same topic and message selector value has been specified, then this method creates a MessageConsumer on the existing subscription.

A non-durable shared subscription is used by a client which needs to be able to share the work of receiving messages from a topic subscription amongst multiple consumers. A non-durable shared subscription may therefore have more than one consumer. Each message from the subscription will be delivered to only one of the consumers on that subscription. Such a subscription is not persisted and will be deleted (together with any undelivered messages associated with it) when there are no consumers on it. The term "consumer" here means a MessageConsumer or JMSConsumer object in any client.

A shared non-durable subscription is identified by a name specified by the client and by the client identifier (which may be unset). An application which subsequently wishes to create a consumer on that shared non-durable subscription must use the same client identifier.

If a shared non-durable subscription already exists with the same name and client identifier (if set) but a different topic or message selector has been specified, and there is a consumer already active (i.e. not closed) on the subscription, then a JMSException will be thrown.

There is no restriction on durable subscriptions and shared non-durable subscriptions having the same name and clientId (which may be unset). Such subscriptions would be completely separate.

Parameters:

topic - the Topic to subscribe to

sharedSubscriptionName - the name used to identify the shared non-durable subscription

Returns:

A shared non-durable subscription with the specified name on the specified topic.

Throws:

JMSException - if the session fails to create the shared non-durable subscription and MessageConsumer due to some internal error.

InvalidDestinationException - if an invalid topic is specified.

InvalidSelectorException - if the message selector is invalid.

Since:

JMS 2.0

createSharedConsumer

MessageConsumer createSharedConsumer(Topic topic,
 String sharedSubscriptionName,
 String messageSelector)
                              throws JMSException

Creates a shared non-durable subscription with the specified name on the specified topic (if one does not already exist) specifying a message selector, and creates a consumer on that subscription.

If a shared non-durable subscription already exists with the same name and client identifier (if set), and the same topic and message selector has been specified, then this method creates a MessageConsumer on the existing subscription.

A non-durable shared subscription is used by a client which needs to be able to share the work of receiving messages from a topic subscription amongst multiple consumers. A non-durable shared subscription may therefore have more than one consumer. Each message from the subscription will be delivered to only one of the consumers on that subscription. Such a subscription is not persisted and will be deleted (together with any undelivered messages associated with it) when there are no consumers on it. The term "consumer" here means a MessageConsumer or JMSConsumer object in any client.

A shared non-durable subscription is identified by a name specified by the client and by the client identifier (which may be unset). An application which subsequently wishes to create a consumer on that shared non-durable subscription must use the same client identifier.

If a shared non-durable subscription already exists with the same name and client identifier (if set) but a different topic or message selector has been specified, and there is a consumer already active (i.e. not closed) on the subscription, then a JMSException will be thrown.

There is no restriction on durable subscriptions and shared non-durable subscriptions having the same name and clientId (which may be unset). Such subscriptions would be completely separate.

Parameters:

topic - the Topic to subscribe to

sharedSubscriptionName - the name used to identify the shared non-durable subscription

messageSelector - only messages with properties matching the message selector expression are added to the shared non-durable subscription. A value of null or an empty string indicates that there is no message selector for the shared non-durable subscription.

Returns:

A shared non-durable subscription with the specified name on the specified topic.

Throws:

JMSException - if the session fails to create the shared non-durable subscription and MessageConsumer due to some internal error.

InvalidDestinationException - if an invalid topic is specified.

InvalidSelectorException - if the message selector is invalid.

Since:

JMS 2.0

createQueue

Queue createQueue(String queueName)
           throws JMSException

Creates a Queue object which encapsulates a specified provider-specific queue name.

The use of provider-specific queue names in an application may render the application non-portable. Portable applications are recommended to not use this method but instead look up an administratively-defined Queue object using JNDI.

Note that this method simply creates an object that encapsulates the name of a queue. It does not create the physical queue in the Jakarta Messaging provider. Jakarta Messaging does not provide a method to create the physical queue, since this would be specific to a given Jakarta Messaging provider. Creating a physical queue is provider-specific and is typically an administrative task performed by an administrator, though some providers may create them automatically when needed. The one exception to this is the creation of a temporary queue, which is done using the createTemporaryQueue method.

Parameters:

queueName - A provider-specific queue name

Returns:

a Queue object which encapsulates the specified name

Throws:

JMSException - if a Queue object cannot be created due to some internal error

createTopic

Topic createTopic(String topicName)
           throws JMSException

Creates a Topic object which encapsulates a specified provider-specific topic name.

The use of provider-specific topic names in an application may render the application non-portable. Portable applications are recommended to not use this method but instead look up an administratively-defined Topic object using JNDI.

Note that this method simply creates an object that encapsulates the name of a topic. It does not create the physical topic in the Jakarta Messaging provider. Jakarta Messaging does not provide a method to create the physical topic, since this would be specific to a given Jakarta Messaging provider. Creating a physical topic is provider-specific and is typically an administrative task performed by an administrator, though some providers may create them automatically when needed. The one exception to this is the creation of a temporary topic, which is done using the createTemporaryTopic method.

Parameters:

topicName - A provider-specific topic name

Returns:

a Topic object which encapsulates the specified name

Throws:

JMSException - if a Topic object cannot be created due to some internal error

createDurableSubscriber

TopicSubscriber createDurableSubscriber(Topic topic,
 String name)
                                 throws JMSException

Creates an unshared durable subscription on the specified topic (if one does not already exist) and creates a consumer on that durable subscription. This method creates the durable subscription without a message selector and with a noLocal value of false.

A durable subscription is used by an application which needs to receive all the messages published on a topic, including the ones published when there is no active consumer associated with it. The Jakarta Messaging provider retains a record of this durable subscription and ensures that all messages from the topic's publishers are retained until they are delivered to, and acknowledged by, a consumer on this durable subscription or until they have expired.

A durable subscription will continue to accumulate messages until it is deleted using the unsubscribe method.

This method may only be used with unshared durable subscriptions. Any durable subscription created using this method will be unshared. This means that only one active (i.e. not closed) consumer on the subscription may exist at a time. The term "consumer" here means a TopicSubscriber, MessageConsumer or JMSConsumer object in any client.

An unshared durable subscription is identified by a name specified by the client and by the client identifier, which must be set. An application which subsequently wishes to create a consumer on that unshared durable subscription must use the same client identifier.

If an unshared durable subscription already exists with the same name and client identifier, and the same topic, message selector and noLocal value has been specified, and there is no consumer already active (i.e. not closed) on the durable subscription then this method creates a TopicSubscriber on the existing durable subscription.

If an unshared durable subscription already exists with the same name and client identifier, and there is a consumer already active (i.e. not closed) on the durable subscription, then a JMSException will be thrown.

If an unshared durable subscription already exists with the same name and client identifier but a different topic, message selector or noLocal value has been specified, and there is no consumer already active (i.e. not closed) on the durable subscription then this is equivalent to unsubscribing (deleting) the old one and creating a new one.

A shared durable subscription and an unshared durable subscription may not have the same name and client identifier. If a shared durable subscription already exists with the same name and client identifier then a JMSException is thrown.

There is no restriction on durable subscriptions and shared non-durable subscriptions having the same name and clientId. Such subscriptions would be completely separate.

This method is identical to the corresponding createDurableConsumer method except that it returns a TopicSubscriber rather than a MessageConsumer to represent the consumer.

Parameters:

topic - the non-temporary Topic to subscribe to

name - the name used to identify this subscription

Returns:

An unshared durable subscription on the specified topic.

Throws:

InvalidDestinationException - if an invalid topic is specified.

IllegalStateException - if the client identifier is unset

JMSException -

• if the session fails to create the unshared durable subscription and TopicSubscriber due to some internal error
• if an unshared durable subscription already exists with the same name and client identifier, and there is a consumer already active
• if a shared durable subscription already exists with the same name and client identifier

Since:

JMS 1.1

createDurableSubscriber

TopicSubscriber createDurableSubscriber(Topic topic,
 String name,
 String messageSelector,
 boolean noLocal)
                                 throws JMSException

Creates an unshared durable subscription on the specified topic (if one does not already exist), specifying a message selector and the noLocal parameter, and creates a consumer on that durable subscription.

A durable subscription is used by an application which needs to receive all the messages published on a topic, including the ones published when there is no active consumer associated with it. The Jakarta Messaging provider retains a record of this durable subscription and ensures that all messages from the topic's publishers are retained until they are delivered to, and acknowledged by, a consumer on this durable subscription or until they have expired.

A durable subscription will continue to accumulate messages until it is deleted using the unsubscribe method.

This method may only be used with unshared durable subscriptions. Any durable subscription created using this method will be unshared. This means that only one active (i.e. not closed) consumer on the subscription may exist at a time. The term "consumer" here means a TopicSubscriber, MessageConsumer or JMSConsumer object in any client.

An unshared durable subscription is identified by a name specified by the client and by the client identifier, which must be set. An application which subsequently wishes to create a consumer on that unshared durable subscription must use the same client identifier.

If an unshared durable subscription already exists with the same name and client identifier, and the same topic, message selector and noLocal value has been specified, and there is no consumer already active (i.e. not closed) on the durable subscription then this method creates a TopicSubscriber on the existing durable subscription.

If an unshared durable subscription already exists with the same name and client identifier, and there is a consumer already active (i.e. not closed) on the durable subscription, then a JMSException will be thrown.

If an unshared durable subscription already exists with the same name and client identifier but a different topic, message selector or noLocal value has been specified, and there is no consumer already active (i.e. not closed) on the durable subscription then this is equivalent to unsubscribing (deleting) the old one and creating a new one.

If noLocal is set to true then any messages published to the topic using this session's connection, or any other connection with the same client identifier, will not be added to the durable subscription.

A shared durable subscription and an unshared durable subscription may not have the same name and client identifier. If a shared durable subscription already exists with the same name and client identifier then a JMSException is thrown.

There is no restriction on durable subscriptions and shared non-durable subscriptions having the same name and clientId. Such subscriptions would be completely separate.

This method is identical to the corresponding createDurableConsumer method except that it returns a TopicSubscriber rather than a MessageConsumer to represent the consumer.

Parameters:

topic - the non-temporary Topic to subscribe to

name - the name used to identify this subscription

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

noLocal - if true then any messages published to the topic using this session's connection, or any other connection with the same client identifier, will not be added to the durable subscription.

Returns:

An unshared durable subscription on the specified topic.

Throws:

InvalidDestinationException - if an invalid topic is specified.

InvalidSelectorException - if the message selector is invalid.

IllegalStateException - if the client identifier is unset

JMSException -

• if the session fails to create the unshared durable subscription and TopicSubscriber due to some internal error
• if an unshared durable subscription already exists with the same name and client identifier, and there is a consumer already active
• if a shared durable subscription already exists with the same name and client identifier

Since:

JMS 1.1

createDurableConsumer

MessageConsumer createDurableConsumer(Topic topic,
 String name)
                               throws JMSException

Creates an unshared durable subscription on the specified topic (if one does not already exist) and creates a consumer on that durable subscription. This method creates the durable subscription without a message selector and with a noLocal value of false.

A durable subscription is used by an application which needs to receive all the messages published on a topic, including the ones published when there is no active consumer associated with it. The Jakarta Messaging provider retains a record of this durable subscription and ensures that all messages from the topic's publishers are retained until they are delivered to, and acknowledged by, a consumer on this durable subscription or until they have expired.

A durable subscription will continue to accumulate messages until it is deleted using the unsubscribe method.

This method may only be used with unshared durable subscriptions. Any durable subscription created using this method will be unshared. This means that only one active (i.e. not closed) consumer on the subscription may exist at a time. The term "consumer" here means a TopicSubscriber, MessageConsumer or JMSConsumer object in any client.

An unshared durable subscription is identified by a name specified by the client and by the client identifier, which must be set. An application which subsequently wishes to create a consumer on that unshared durable subscription must use the same client identifier.

If an unshared durable subscription already exists with the same name and client identifier, and the same topic, message selector and noLocal value has been specified, and there is no consumer already active (i.e. not closed) on the durable subscription then this method creates a MessageConsumer on the existing durable subscription.

If an unshared durable subscription already exists with the same name and client identifier, and there is a consumer already active (i.e. not closed) on the durable subscription, then a JMSException will be thrown.

If an unshared durable subscription already exists with the same name and client identifier but a different topic, message selector or noLocal value has been specified, and there is no consumer already active (i.e. not closed) on the durable subscription then this is equivalent to unsubscribing (deleting) the old one and creating a new one.

A shared durable subscription and an unshared durable subscription may not have the same name and client identifier. If a shared durable subscription already exists with the same name and client identifier then a JMSException is thrown.

There is no restriction on durable subscriptions and shared non-durable subscriptions having the same name and clientId. Such subscriptions would be completely separate.

This method is identical to the corresponding createDurableSubscriber method except that it returns a MessageConsumer rather than a TopicSubscriber to represent the consumer.

Parameters:

topic - the non-temporary Topic to subscribe to

name - the name used to identify this subscription

Returns:

An unshared durable subscription on the specified topic.

Throws:

InvalidDestinationException - if an invalid topic is specified.

IllegalStateException - if the client identifier is unset

JMSException -

• if the session fails to create the unshared durable subscription and MessageConsumer due to some internal error
• if an unshared durable subscription already exists with the same name and client identifier, and there is a consumer already active
• if a shared durable subscription already exists with the same name and client identifier

Since:

JMS 2.0

createDurableConsumer

MessageConsumer createDurableConsumer(Topic topic,
 String name,
 String messageSelector,
 boolean noLocal)
                               throws JMSException

Creates an unshared durable subscription on the specified topic (if one does not already exist), specifying a message selector and the noLocal parameter, and creates a consumer on that durable subscription.

A durable subscription is used by an application which needs to receive all the messages published on a topic, including the ones published when there is no active consumer associated with it. The Jakarta Messaging provider retains a record of this durable subscription and ensures that all messages from the topic's publishers are retained until they are delivered to, and acknowledged by, a consumer on this durable subscription or until they have expired.

A durable subscription will continue to accumulate messages until it is deleted using the unsubscribe method.

This method may only be used with unshared durable subscriptions. Any durable subscription created using this method will be unshared. This means that only one active (i.e. not closed) consumer on the subscription may exist at a time. The term "consumer" here means a TopicSubscriber, MessageConsumer or JMSConsumer object in any client.

An unshared durable subscription is identified by a name specified by the client and by the client identifier, which must be set. An application which subsequently wishes to create a consumer on that unshared durable subscription must use the same client identifier.

If an unshared durable subscription already exists with the same name and client identifier, and the same topic, message selector and noLocal value has been specified, and there is no consumer already active (i.e. not closed) on the durable subscription then this method creates a MessageConsumer on the existing durable subscription.

If an unshared durable subscription already exists with the same name and client identifier, and there is a consumer already active (i.e. not closed) on the durable subscription, then a JMSException will be thrown.

If an unshared durable subscription already exists with the same name and client identifier but a different topic, message selector or noLocal value has been specified, and there is no consumer already active (i.e. not closed) on the durable subscription then this is equivalent to unsubscribing (deleting) the old one and creating a new one.

If noLocal is set to true then any messages published to the topic using this session's connection, or any other connection with the same client identifier, will not be added to the durable subscription.

A shared durable subscription and an unshared durable subscription may not have the same name and client identifier. If a shared durable subscription already exists with the same name and client identifier then a JMSException is thrown.

There is no restriction on durable subscriptions and shared non-durable subscriptions having the same name and clientId. Such subscriptions would be completely separate.

This method is identical to the corresponding createDurableSubscriber method except that it returns a MessageConsumer rather than a TopicSubscriber to represent the consumer.

Parameters:

topic - the non-temporary Topic to subscribe to

name - the name used to identify this subscription

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

noLocal - if true then any messages published to the topic using this session's connection, or any other connection with the same client identifier, will not be added to the durable subscription.

Returns:

An unshared durable subscription on the specified topic.

Throws:

InvalidDestinationException - if an invalid topic is specified.

InvalidSelectorException - if the message selector is invalid.

IllegalStateException - if the client identifier is unset

JMSException -

• if the session fails to create the unshared durable subscription and MessageConsumer due to some internal error
• if an unshared durable subscription already exists with the same name and client identifier, and there is a consumer already active
• if a shared durable subscription already exists with the same name and client identifier

Since:

JMS 2.0

createSharedDurableConsumer

MessageConsumer createSharedDurableConsumer(Topic topic,
 String name)
                                     throws JMSException

Creates a shared durable subscription on the specified topic (if one does not already exist), specifying a message selector and the noLocal parameter, and creates a consumer on that durable subscription. This method creates the durable subscription without a message selector.

A durable subscription is used by an application which needs to receive all the messages published on a topic, including the ones published when there is no active consumer associated with it. The Jakarta Messaging provider retains a record of this durable subscription and ensures that all messages from the topic's publishers are retained until they are delivered to, and acknowledged by, a consumer on this durable subscription or until they have expired.

A durable subscription will continue to accumulate messages until it is deleted using the unsubscribe method.

This method may only be used with shared durable subscriptions. Any durable subscription created using this method will be shared. This means that multiple active (i.e. not closed) consumers on the subscription may exist at the same time. The term "consumer" here means a MessageConsumer or JMSConsumer object in any client.

A shared durable subscription is identified by a name specified by the client and by the client identifier (which may be unset). An application which subsequently wishes to create a consumer on that shared durable subscription must use the same client identifier.

If a shared durable subscription already exists with the same name and client identifier (if set), and the same topic and message selector has been specified, then this method creates a MessageConsumer on the existing shared durable subscription.

If a shared durable subscription already exists with the same name and client identifier (if set) but a different topic or message selector has been specified, and there is no consumer already active (i.e. not closed) on the durable subscription then this is equivalent to unsubscribing (deleting) the old one and creating a new one.

If a shared durable subscription already exists with the same name and client identifier (if set) but a different topic or message selector has been specified, and there is a consumer already active (i.e. not closed) on the durable subscription, then a JMSException will be thrown.

A shared durable subscription and an unshared durable subscription may not have the same name and client identifier (if set). If an unshared durable subscription already exists with the same name and client identifier (if set) then a JMSException is thrown.

There is no restriction on durable subscriptions and shared non-durable subscriptions having the same name and clientId (which may be unset). Such subscriptions would be completely separate.

Parameters:

topic - the non-temporary Topic to subscribe to

name - the name used to identify this subscription

Returns:

A shared durable subscription on the specified topic.

Throws:

JMSException -

• if the session fails to create the shared durable subscription and MessageConsumer due to some internal error
• if a shared durable subscription already exists with the same name and client identifier, but a different topic or message selector, and there is a consumer already active
• if an unshared durable subscription already exists with the same name and client identifier

InvalidDestinationException - if an invalid topic is specified.

Since:

JMS 2.0

createSharedDurableConsumer

MessageConsumer createSharedDurableConsumer(Topic topic,
 String name,
 String messageSelector)
                                     throws JMSException

Creates a shared durable subscription on the specified topic (if one does not already exist), specifying a message selector, and creates a consumer on that durable subscription.

A durable subscription is used by an application which needs to receive all the messages published on a topic, including the ones published when there is no active consumer associated with it. The Jakarta Messaging provider retains a record of this durable subscription and ensures that all messages from the topic's publishers are retained until they are delivered to, and acknowledged by, a consumer on this durable subscription or until they have expired.

A durable subscription will continue to accumulate messages until it is deleted using the unsubscribe method.

This method may only be used with shared durable subscriptions. Any durable subscription created using this method will be shared. This means that multiple active (i.e. not closed) consumers on the subscription may exist at the same time. The term "consumer" here means a MessageConsumer or JMSConsumer object in any client.

A shared durable subscription is identified by a name specified by the client and by the client identifier (which may be unset). An application which subsequently wishes to create a consumer on that shared durable subscription must use the same client identifier.

If a shared durable subscription already exists with the same name and client identifier (if set), and the same topic and message selector has been specified, then this method creates a MessageConsumer on the existing shared durable subscription.

If a shared durable subscription already exists with the same name and client identifier (if set) but a different topic or message selector has been specified, and there is no consumer already active (i.e. not closed) on the durable subscription then this is equivalent to unsubscribing (deleting) the old one and creating a new one.

If a shared durable subscription already exists with the same name and client identifier (if set) but a different topic or message selector has been specified, and there is a consumer already active (i.e. not closed) on the durable subscription, then a JMSException will be thrown.

A shared durable subscription and an unshared durable subscription may not have the same name and client identifier (if set). If an unshared durable subscription already exists with the same name and client identifier (if set) then a JMSException is thrown.

There is no restriction on durable subscriptions and shared non-durable subscriptions having the same name and clientId (which may be unset). Such subscriptions would be completely separate.

Parameters:

topic - the non-temporary Topic to subscribe to

name - the name used to identify this subscription

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

Returns:

A shared durable subscription on the specified topic.

Throws:

JMSException -

• if the session fails to create the shared durable subscription and MessageConsumer due to some internal error
• if a shared durable subscription already exists with the same name and client identifier, but a different topic or message selector, and there is a consumer already active
• if an unshared durable subscription already exists with the same name and client identifier

InvalidDestinationException - if an invalid topic is specified.

InvalidSelectorException - if the message selector is invalid.

Since:

JMS 2.0

createBrowser

QueueBrowser createBrowser(Queue queue)
                    throws JMSException

Creates a QueueBrowser object to peek at the messages on the specified queue.

Parameters:

queue - the queue to access

Returns:

A QueueBrowser object to peek at the messages on the specified queue.

Throws:

JMSException - if the session fails to create a browser due to some internal error.

InvalidDestinationException - if an invalid destination is specified

Since:

JMS 1.1

createBrowser

QueueBrowser createBrowser(Queue queue,
 String messageSelector)
                    throws JMSException

Creates a QueueBrowser object to peek at the messages on the specified queue using a message selector.

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.

Returns:

A QueueBrowser object to peek at the messages on the specified queue.

Throws:

JMSException - if the session fails to create a browser due to some internal error.

InvalidDestinationException - if an invalid destination is specified

InvalidSelectorException - if the message selector is invalid.

Since:

JMS 1.1

createTemporaryQueue

TemporaryQueue createTemporaryQueue()
                             throws JMSException

Creates a TemporaryQueue object. Its lifetime will be that of the Connection unless it is deleted earlier.

Returns:

a temporary queue identity

Throws:

JMSException - if the session fails to create a temporary queue due to some internal error.

Since:

JMS 1.1

createTemporaryTopic

TemporaryTopic createTemporaryTopic()
                             throws JMSException

Creates a TemporaryTopic object. Its lifetime will be that of the Connection unless it is deleted earlier.

Returns:

a temporary topic identity

Throws:

JMSException - if the session fails to create a temporary topic due to some internal error.

Since:

JMS 1.1

unsubscribe

void unsubscribe(String name)
          throws JMSException

Unsubscribes a durable subscription that has been created by a client.

This method deletes the state being maintained on behalf of the subscriber by its provider.

A durable subscription is identified by a name specified by the client and by the client identifier if set. If the client identifier was set when the durable subscription was created then a client which subsequently wishes to use this method to delete a durable subscription must use the same client identifier.

It is erroneous for a client to delete a durable subscription while there is an active (not closed) consumer for the subscription, or while a consumed message is part of a pending transaction or has not been acknowledged in the session.

Parameters:

name - the name used to identify this subscription

Throws:

JMSException - if the session fails to unsubscribe to the durable subscription due to some internal error.

InvalidDestinationException - if an invalid subscription name is specified.

Since:

JMS 1.1