TBTSession Class Reference

A Session object is a single-threaded context for producing and consuming messages. More...

Inheritance diagram for TBTSession:

Public Member Functions
	Close ()
	Closes the session. More...
	Commit ()
	If this is a transactional session then commit all message send and acknowledgements for producers and consumers in this session. More...
IBytesMessage	CreateBytesMessage ()
	Creates a IBytesMessage object. More...
IMessage	CreateMessage ()
	Creates a IMessage object. More...
ITextMessage	CreateTextMessage ()
	Creates a ITextMessage object. More...
ITextMessage	CreateTextMessage (const string Text)
	Creates an initialized ITextMessage object. More...
IMapMessage	CreateMapMessage ()
	Creates a MapMessage object. More...
IMessageConsumer	CreateConsumer (const IDestination Destination)
	Creates a IMessageConsumer for the specified destination. More...
IMessageConsumer	CreateConsumer (const IDestination Destination, const string MessageSelector)
	Creates a IMessageConsumer for the specified destination, using a message selector. More...
IMessageConsumer	CreateConsumer (const IDestination Destination, const string MessageSelector, const Boolean NoLocal)
	Creates IMessageConsumer for the specified destination, using a message selector. More...
IObjectMessage	CreateObjectMessage ()
	Creates an IObjectMessage object. More...
IObjectMessage	CreateObjectMessage (const TObject AObject)
	Creates an initialized IObjectMessage object. More...
ITopicSubscriber	CreateDurableSubscriber (const ITopic Topic, const string Name)
	Creates a durable subscriber to the specified topic. More...
ITopicSubscriber	CreateDurableSubscriber (const ITopic Topic, const string Name, const string MessageSelector, const Boolean NoLocal)
	Creates a durable subscriber to the specified topic, using a message selector and specifying whether messages published by its own connection should be delivered to it.
IMessageProducer	CreateProducer (const IDestination Destination)
	Creates a producer of messages on a given destination.
IQueue	CreateQueue (const string QueueName)
	Creates a queue identity given a IQueue name. More...
ITopic	CreateTopic (const string TopicName)
	Creates a topic identity given a ITopic name. More...
ITemporaryQueue	CreateTemporaryQueue ()
	Creates a TemporaryQueue object. More...
ITemporaryTopic	CreateTemporaryTopic ()
	Creates a TemporaryTopic object. More...
IQueueBrowser	CreateBrowser (const string QueueName)
	Creates a QueueBrowser object to peek at the messages on the specified queue. More...
	Rollback ()
	If this is a transactional session then rollback all message send and acknowledgements for producers and consumers in this session. More...
	Send (const IDestination Destination, const IMessage Message, const TJMSDeliveryMode DeliveryMode, const Byte Priority, const Cardinal TimeToLive, const Integer SendTimeOut)
	Sends the message for dispatch by the broker. More...
	Unsubscribe (const string Destination, const string Name)
	Unsubscribes a durable subscription that has been created by a client. More...

Public Attributes
TAcknowledgementMode	AcknowledgeMode
	The acknowledgement mode of the session. More...
TBTConnection	Connection
	The connection of the session. More...
Boolean	Running
	Returns True if the session has started. More...
Boolean	Transacted
	Whether the session uses transactions. More...
TBTTransactionContext	TransactionContext
	The transaction context of the session. More...

Protected Member Functions
	CheckClosed ()
	Check if the session is closed. More...

Detailed Description

A Session object is a single-threaded context for producing and consuming messages.

A session serves several purposes:

• It is a factory for its message producers and consumers.
• It supplies message factories.
• It provides a way to create IQueue or ITopic objects.
• It supports a single series of transactions.

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

One typical use is to have a thread block on a synchronous IMessageConsumer until a message arrives. The thread may then use one or more of the ISession'sIMessageProducers.

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.

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.

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.

Member Function Documentation

CheckClosed()

TBTSession::CheckClosed ( )

protected

Check if the session is closed.

It is used for ensuring that the session is open before performing various operations.

Exceptions

EIllegalStateException

if the Session is closed

Close()

TBTSession::Close

(

)

Closes the 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.

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

This method is the only Session method that can be called concurrently. Invoking any other Session method on a closed session must throw a IllegalStateException.

Commit()

TBTSession::Commit

(

)

If this is a transactional session then commit all message send and acknowledgements for producers and consumers in this session.

Exceptions

EJMSException

CreateBrowser()

IQueueBrowser TBTSession::CreateBrowser

(

const string

QueueName

)

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

This feature requires STOMP 1.1

CreateBytesMessage()

IBytesMessage TBTSession::CreateBytesMessage

(

)

Creates a IBytesMessage object.

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

Returns

the IBytesMessage

CreateConsumer() [1/3]

IMessageConsumer TBTSession::CreateConsumer

(

const IDestination

Destination

)

Creates a IMessageConsumer for the specified destination.

Since IQueue and ITopic both inherit from IDestination, they can be used in the destination parameter to create a IMessageConsumer.

Parameters

Destination

the IDestination to access.

Returns

the IMessageConsumer

CreateConsumer() [2/3]

IMessageConsumer TBTSession::CreateConsumer	(	const IDestination	Destination,
		const string	MessageSelector
	)

Creates a IMessageConsumer for the specified destination, using a message selector.

Since IQueue and ITopic both inherit from IDestination, they can be used in the destination parameter to create a IMessageConsumer.

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

Parameters

Destination	the IDestination to access
MessageSelector	only messages with properties matching the message selector expression are delivered. An empty string indicates that there is no message selector for the message consumer.

Returns

the MessageConsumer

CreateConsumer() [3/3]

IMessageConsumer TBTSession::CreateConsumer	(	const IDestination	Destination,
		const string	MessageSelector,
		const Boolean	NoLocal
	)

Creates IMessageConsumer for the specified destination, using a message selector.

This method can specify whether messages published by its own connection should be delivered to it, if the destination is a topic.

Since IQueue and ITopic both inherit from IDestination, they can be used in the destination parameter to create a IMessageConsumer.

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

In some cases, a connection may both publish and subscribe to a topic. The consumer noLocal attribute allows a consumer to inhibit the delivery of messages published by its own connection. The default value for this attribute is False. The noLocal value must be supported by destinations that are topics.

Parameters

Destination	the IDestination to access
MessageSelector	only messages with properties matching the message selector expression are delivered. An empty string indicates that there is no message selector for the message consumer.
NoLocal	- if true, and the destination is a topic, inhibits the delivery of messages published by its own connection. The behavior for NoLocal is not specified if the destination is a queue.

Returns

the MessageConsumer

CreateDurableSubscriber()

ITopicSubscriber TBTSession::CreateDurableSubscriber	(	const ITopic	Topic,
		const string	Name
	)

Creates a durable subscriber to the specified topic.

If a client needs to receive all the messages published on a topic, including the ones published while the subscriber is inactive, it uses a durable ITopicSubscriber. The message provider retains a record of this durable subscription and insures that all messages from the topic's publishers are retained until they are acknowledged by this durable subscriber or they have expired.

Sessions with durable subscribers must always provide the same client identifier. In addition, each client must specify a name that uniquely identifies (within client identifier) each durable subscription it creates. Only one session at a time can have a TopicSubscriber for a particular durable subscription.

A client can change an existing durable subscription by creating a durable TopicSubscriber with the same name and a new topic and/or message selector. Changing a durable subscriber is equivalent to unsubscribing (deleting) the old one and creating a new one.

In some cases, a connection may both publish and subscribe to a topic. The subscriber NoLocal attribute allows a subscriber to inhibit the delivery of messages published by its own connection. The default value for this attribute is false.

See also

http://activemq.apache.org/stomp.html

Parameters

Topic	- the non-temporary ITopic to subscribe to
Name	- the name used to identify this subscription

Returns

the ITopicSubscriber

Exceptions

EJMSException

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

CreateMapMessage()

IMapMessage TBTSession::CreateMapMessage

(

)

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.

Returns

an IMapMessage

CreateMessage()

IMessage TBTSession::CreateMessage

(

)

Creates a IMessage object.

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

Returns

an IMessage

CreateObjectMessage() [1/2]

IObjectMessage TBTSession::CreateObjectMessage

(

)

Creates an IObjectMessage object.

An IObjectMessage object is used to send a message that contains a serializable object.

CreateObjectMessage() [2/2]

IObjectMessage TBTSession::CreateObjectMessage

(

const TObject

AObject

)

Creates an initialized IObjectMessage object.

An IObjectMessage object is used to send a message that contains a serializable object.

Parameters

AObject

the object to use to initialize this message

CreateQueue()

IQueue TBTSession::CreateQueue

(

const string

QueueName

)

Creates a queue identity given a IQueue name.

This facility is provided for the rare cases where clients need to dynamically manipulate queue identity. It allows the creation of a queue identity with a provider-specific name. Clients that depend on this ability are not portable.

Note that this method is not for creating the physical queue. The physical creation of queues is an administrative task and is not to be initiated by the API.

Parameters

QueueName

the name of this IQueue

Returns

a IQueue with the given name

CreateTemporaryQueue()

ITemporaryQueue TBTSession::CreateTemporaryQueue

(

)

Creates a TemporaryQueue object.

Its lifetime will be that of the Connection unless it is deleted earlier.

CreateTemporaryTopic()

ITemporaryTopic TBTSession::CreateTemporaryTopic

(

)

Creates a TemporaryTopic object.

Its lifetime will be that of the Connection unless it is deleted earlier.

CreateTextMessage() [1/2]

ITextMessage TBTSession::CreateTextMessage

(

)

Creates a ITextMessage object.

A ITextMessage object is used to send a message containing a String object.

Returns

an ITextMessage

CreateTextMessage() [2/2]

ITextMessage TBTSession::CreateTextMessage

(

const string

Text

)

Creates an initialized ITextMessage object.

A ITextMessage object is used to send a message containing a String.

Parameters

Text	the string used to initialize this message

Returns

an ITextMessage

CreateTopic()

ITopic TBTSession::CreateTopic

(

const string

TopicName

)

Creates a topic identity given a ITopic name.

This facility is provided for the rare cases where clients need to dynamically manipulate topic identity. This allows the creation of a topic identity with a provider-specific name. Clients that depend on this ability are not portable.

Note that this method is not for creating the physical topic. The physical creation of topics is an administrative task and is not to be initiated by the API.

Parameters

TopicName

the name of this ITopic

Returns

a ITopic with the given name

Rollback()

TBTSession::Rollback

(

)

If this is a transactional session then rollback all message send and acknowledgements for producers and consumers in this session.

Exceptions

EJMSException

Send()

TBTSession::Send	(	const IDestination	Destination,
		const IMessage	Message,
		const TJMSDeliveryMode	DeliveryMode,
		const Byte	Priority,
		const Cardinal	TimeToLive,
		const Integer	SendTimeOut
	)

Sends the message for dispatch by the broker.

Parameters

Destination	- message destination.
Message	- message to be sent.
DeliveryMode	- message delivery mode.
Priority	- message priority.
TimeToLive	- message expiration.
SendTimeOut	- send time out.

Unsubscribe()

TBTSession::Unsubscribe	(	const string	Destination,
		const string	Name
	)

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

Parameters

Destination	- the destination name
Name	- the name used to identify this subscription

Exceptions

EJMSException

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

Member Data Documentation

AcknowledgeMode

TAcknowledgementMode TBTSession::AcknowledgeMode

The acknowledgement mode of the session.

See also

GetAcknowledgeMode For reading

Connection

TBTConnection TBTSession::Connection

The connection of the session.

See also

GetConnection For reading

Running

Boolean TBTSession::Running

Returns True if the session has started.

See also

FStarted For reading

Transacted

Boolean TBTSession::Transacted

Whether the session uses transactions.

See also

GetTransacted For reading

TransactionContext

TBTTransactionContext TBTSession::TransactionContext

The transaction context of the session.

See also

FTransactionContext For reading