Habari Client for OpenMQ  6.0
Object Pascal STOMP client library for OpenMQ
TBTSession Class Reference

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

Inheritance diagram for TBTSession:
ISession

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. More...
 
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
EIllegalStateExceptionif 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
Destinationthe 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
Destinationthe IDestination to access
MessageSelectoronly 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
Destinationthe IDestination to access
MessageSelectoronly 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() [1/2]

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.

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.

◆ CreateDurableSubscriber() [2/2]

ITopicSubscriber TBTSession::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.

Since
1.5

◆ 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
AObjectthe 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
QueueNamethe 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.

See also
http://download.oracle.com/javaee/5/api/javax/jms/Session.html#createTemporaryQueue()

◆ CreateTemporaryTopic()

ITemporaryTopic TBTSession::CreateTemporaryTopic ( )

Creates a TemporaryTopic object.

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

See also
http://download.oracle.com/javaee/5/api/javax/jms/Session.html#createTemporaryTopic()

◆ 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
Textthe 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
TopicNamethe 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.

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

amTransactional This value is returned from the method getAcknowledgeMode if the session is transacted.

amClientAcknowledge With this acknowledgment mode, the client acknowledges a consumed message by calling the message's acknowledge method.

amAutoAcknowledge 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.

amClientIndividual Broker specific mode which allows to acknowledge an individual message without acknowledging all preceding messages

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