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| javax.jms.Session
| Session | | public interface Session extends Runnable(Code) | | 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 JMS 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 connection
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 JMS 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 JMS API does not require support for JTA; however, it does define
how a provider supplies this support.
Although it is also possible for a JMS client to handle distributed
transactions directly, it is unlikely that many JMS clients will do this.
Support for JTA in the JMS API is targeted at systems vendors who will be
integrating the JMS API into their application server products.
See Also: javax.jms.QueueSession
See Also: javax.jms.TopicSession
See Also: javax.jms.XASession |
| Field Summary | |
| final static 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. | | final static int | CLIENT_ACKNOWLEDGE
With this acknowledgment mode, the client acknowledges a consumed
message by calling the message's acknowledge method. | | final static int | DUPS_OK_ACKNOWLEDGE
This acknowledgment mode instructs the session to lazily acknowledge
the delivery of messages. | | final static int | SESSION_TRANSACTED
This value is returned from the method
getAcknowledgeMode if the session is transacted. |
| Method Summary | |
| void | close()
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. | | 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.
Parameters:
queue - the queue to access
Parameters:
messageSelector - only messages with properties matching themessage selector expression are delivered. | | BytesMessage | createBytesMessage()
Creates a BytesMessage object. | | public MessageConsumer | createConsumer(Destination destination)
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. | | MessageConsumer | createConsumer(Destination destination, java.lang.String messageSelector)
Creates a MessageConsumer for the specified destination,
using a message selector. | | MessageConsumer | createConsumer(Destination destination, java.lang.String messageSelector, boolean NoLocal)
Creates MessageConsumer for the specified destination, using a
message selector. | | TopicSubscriber | createDurableSubscriber(Topic topic, 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 TopicSubscriber. | | TopicSubscriber | createDurableSubscriber(Topic topic, String name, String messageSelector, 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.
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 TopicSubscriber. | | 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. | | public MessageProducer | createProducer(Destination destination)
Creates a MessageProducer to send messages to the specified
destination.
A client uses a MessageProducer object to send
messages to a destination. | | Queue | createQueue(String queueName)
Creates a queue identity given a Queue name.
This facility is provided for the rare cases where clients need to
dynamically manipulate queue identity. | | 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 identity given a Topic name.
This facility is provided for the rare cases where clients need to
dynamically manipulate topic identity. | | 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.
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.
| | void | rollback()
Rolls back any messages done in this transaction and releases any locks
currently held. | | public void | run()
Optional operation, intended to be used only by Application Servers,
not by ordinary JMS 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. |
| AUTO_ACKNOWLEDGE | | final static int AUTO_ACKNOWLEDGE(Code) | | 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.
|
| CLIENT_ACKNOWLEDGE | | final static int CLIENT_ACKNOWLEDGE(Code) | | 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 JMS 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: javax.jms.Message.acknowledge |
| DUPS_OK_ACKNOWLEDGE | | final static int DUPS_OK_ACKNOWLEDGE(Code) | | 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 JMS 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.
|
| SESSION_TRANSACTED | | final static int SESSION_TRANSACTED(Code) | | This value is returned from the method
getAcknowledgeMode if the session is transacted.
If a Session is transacted, the acknowledgement mode
is ignored.
|
| close | | void close() throws JMSException(Code) | | 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.
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 JMSException.IllegalStateException. Closing a
closed session must not throw an exception.
exception:
JMSException - if the JMS provider fails to close thesession due to some internal error. |
| commit | | void commit() throws JMSException(Code) | | Commits all messages done in this transaction and releases any locks
currently held.
exception:
JMSException - if the JMS provider fails to commit thetransaction due to some internal error.
exception:
TransactionRolledBackException - if the transactionis rolled back due to some internal errorduring commit.
exception:
IllegalStateException - if the method is not called by a transacted session. |
| createBrowser | | QueueBrowser createBrowser(Queue queue) throws JMSException(Code) | | Creates a QueueBrowser object to peek at the messages on
the specified queue.
Parameters:
queue - the queue to access
exception:
JMSException - if the session fails to create a browserdue to some internal error.
exception:
InvalidDestinationException - if an invalid destinationis specified
since:
1.1 |
| createBrowser | | QueueBrowser createBrowser(Queue queue, String messageSelector) throws JMSException(Code) | | Creates a QueueBrowser object to peek at the messages on
the specified queue using a message selector.
Parameters:
queue - the queue to access
Parameters:
messageSelector - only messages with properties matching themessage selector expression are delivered. A value of null oran empty string indicates that there is no message selector for the message consumer.
exception:
JMSException - if the session fails to create a browserdue to some internal error.
exception:
InvalidDestinationException - if an invalid destinationis specified
exception:
InvalidSelectorException - if the message selector is invalid.
since:
1.1 |
| createBytesMessage | | BytesMessage createBytesMessage() throws JMSException(Code) | | Creates a BytesMessage object. A BytesMessage
object is used to send a message containing a stream of uninterpreted
bytes.
exception:
JMSException - if the JMS provider fails to create this messagedue to some internal error. |
| createConsumer | | public MessageConsumer createConsumer(Destination destination) throws JMSException(Code) | | 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.
exception:
JMSException - if the session fails to create a consumerdue to some internal error.
exception:
InvalidDestinationException - if an invalid destination is specified.
since:
1.1 |
| createConsumer | | MessageConsumer createConsumer(Destination destination, java.lang.String messageSelector) throws JMSException(Code) | | 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
Parameters:
messageSelector - only messages with properties matching themessage selector expression are delivered. A value of null oran empty string indicates that there is no message selector for the message consumer.
exception:
JMSException - if the session fails to create a MessageConsumerdue to some internal error.
exception:
InvalidDestinationException - if an invalid destinationis specified.
exception:
InvalidSelectorException - if the message selector is invalid.
since:
1.1 |
| createConsumer | | MessageConsumer createConsumer(Destination destination, java.lang.String messageSelector, boolean NoLocal) throws JMSException(Code) | | Creates MessageConsumer 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 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.
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 Destination to access
Parameters:
messageSelector - only messages with properties matching themessage selector expression are delivered. A value of null oran empty string indicates that there is no message selector for the message consumer.
Parameters:
NoLocal - - if true, and the destination is a topic,inhibits the delivery of messages publishedby its own connection. The behavior forNoLocal is not specified if the destination is a queue.
exception:
JMSException - if the session fails to create a MessageConsumerdue to some internal error.
exception:
InvalidDestinationException - if an invalid destinationis specified.
exception:
InvalidSelectorException - if the message selector is invalid.
since:
1.1 |
| createDurableSubscriber | | TopicSubscriber createDurableSubscriber(Topic topic, String name) throws JMSException(Code) | | 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 TopicSubscriber. The JMS 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 Topic to subscribe to
Parameters:
name - the name used to identify this subscription
exception:
JMSException - if the session fails to create a subscriberdue to some internal error.
exception:
InvalidDestinationException - if an invalid topic is specified.
since:
1.1 |
| createDurableSubscriber | | TopicSubscriber createDurableSubscriber(Topic topic, String name, String messageSelector, boolean noLocal) throws JMSException(Code) | | 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.
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 TopicSubscriber. The JMS 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 which
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.
An inactive durable subscriber is one that exists but
does not currently have a message consumer associated with it.
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.
Parameters:
topic - the non-temporary Topic to subscribe to
Parameters:
name - the name used to identify this subscription
Parameters:
messageSelector - only messages with properties matching themessage selector expression are delivered. A value of null oran empty string indicates that there is no message selector for the message consumer.
Parameters:
noLocal - if set, inhibits the delivery of messages publishedby its own connection
exception:
JMSException - if the session fails to create a subscriberdue to some internal error.
exception:
InvalidDestinationException - if an invalid topic is specified.
exception:
InvalidSelectorException - if the message selector is invalid.
since:
1.1 |
| createMapMessage | | MapMessage createMapMessage() throws JMSException(Code) | | 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.
exception:
JMSException - if the JMS provider fails to create this messagedue to some internal error. |
| createMessage | | Message createMessage() throws JMSException(Code) | | Creates a Message object. The Message
interface is the root interface of all JMS messages. A
Message object holds all the
standard message header information. It can be sent when a message
containing only header information is sufficient.
exception:
JMSException - if the JMS provider fails to create this messagedue to some internal error. |
| createObjectMessage | | ObjectMessage createObjectMessage() throws JMSException(Code) | | Creates an ObjectMessage object. An
ObjectMessage object is used to send a message
that contains a serializable Java object.
exception:
JMSException - if the JMS provider fails to create this messagedue to some internal error. |
| createObjectMessage | | ObjectMessage createObjectMessage(Serializable object) throws JMSException(Code) | | Creates an initialized ObjectMessage object. An
ObjectMessage object is used
to send a message that contains a serializable Java object.
Parameters:
object - the object to use to initialize this message
exception:
JMSException - if the JMS provider fails to create this messagedue to some internal error. |
| createProducer | | public MessageProducer createProducer(Destination destination) throws JMSException(Code) | | 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.
exception:
JMSException - if the session fails to create a MessageProducerdue to some internal error.
exception:
InvalidDestinationException - if an invalid destinationis specified.
since:
1.1 |
| createQueue | | Queue createQueue(String queueName) throws JMSException(Code) | | Creates a queue identity given a Queue 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 JMS API. The one exception is the
creation of temporary queues, which is accomplished with the
createTemporaryQueue method.
Parameters:
queueName - the name of this Queue a Queue with the given name
exception:
JMSException - if the session fails to create a queuedue to some internal error.
since:
1.1 |
| createStreamMessage | | StreamMessage createStreamMessage() throws JMSException(Code) | | Creates a StreamMessage object. A
StreamMessage object is used to send a
self-defining stream of primitive values in the Java programming
language.
exception:
JMSException - if the JMS provider fails to create this messagedue to some internal error. |
| createTemporaryQueue | | TemporaryQueue createTemporaryQueue() throws JMSException(Code) | | Creates a TemporaryQueue object. Its lifetime will be that
of the Connection unless it is deleted earlier.
a temporary queue identity
exception:
JMSException - if the session fails to create a temporary queuedue to some internal error.
since:
1.1 |
| createTemporaryTopic | | TemporaryTopic createTemporaryTopic() throws JMSException(Code) | | Creates a TemporaryTopic object. Its lifetime will be that
of the Connection unless it is deleted earlier.
a temporary topic identity
exception:
JMSException - if the session fails to create a temporarytopic due to some internal error.
since:
1.1 |
| createTextMessage | | TextMessage createTextMessage() throws JMSException(Code) | | Creates a TextMessage object. A TextMessage
object is used to send a message containing a String
object.
exception:
JMSException - if the JMS provider fails to create this messagedue to some internal error. |
| createTextMessage | | TextMessage createTextMessage(String text) throws JMSException(Code) | | Creates an initialized TextMessage object. A
TextMessage object is used to send
a message containing a String.
Parameters:
text - the string used to initialize this message
exception:
JMSException - if the JMS provider fails to create this messagedue to some internal error. |
| createTopic | | Topic createTopic(String topicName) throws JMSException(Code) | | Creates a topic identity given a Topic 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 JMS API. The one exception is the
creation of temporary topics, which is accomplished with the
createTemporaryTopic method.
Parameters:
topicName - the name of this Topic a Topic with the given name
exception:
JMSException - if the session fails to create a topicdue to some internal error.
since:
1.1 |
| getAcknowledgeMode | | int getAcknowledgeMode() throws JMSException(Code) | | 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.
If the session is not transacted, returns the current acknowledgement mode for the session.If the sessionis transacted, returns SESSION_TRANSACTED.
exception:
JMSException - if the JMS provider fails to return the acknowledgment mode due to some internal error.
See Also: Connection.createSession
since:
1.1 |
| getTransacted | | boolean getTransacted() throws JMSException(Code) | | Indicates whether the session is in transacted mode.
true if the session is in transacted mode
exception:
JMSException - if the JMS provider fails to return the transaction mode due to some internal error. |
| recover | | void recover() throws JMSException(Code) | | 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.
exception:
JMSException - if the JMS provider fails to stop and restartmessage delivery due to some internal error.
exception:
IllegalStateException - if the method is called by a transacted session. |
| rollback | | void rollback() throws JMSException(Code) | | Rolls back any messages done in this transaction and releases any locks
currently held.
exception:
JMSException - if the JMS provider fails to roll back thetransaction due to some internal error.
exception:
IllegalStateException - if the method is not called by a transacted session. |
| run | | public void run()(Code) | | Optional operation, intended to be used only by Application Servers,
not by ordinary JMS clients.
See Also: javax.jms.ServerSession |
| setMessageListener | | void setMessageListener(MessageListener listener) throws JMSException(Code) | | 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 regular JMS clients.
Parameters:
listener - the message listener to associate with this session
exception:
JMSException - if the JMS provider fails to set the message listener due to an internal error.
See Also: javax.jms.Session.getMessageListener
See Also: javax.jms.ServerSessionPool
See Also: javax.jms.ServerSession |
| unsubscribe | | void unsubscribe(String name) throws JMSException(Code) | | 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:
name - the name used to identify this subscription
exception:
JMSException - if the session fails to unsubscribe to the durable subscription due to some internal error.
exception:
InvalidDestinationException - if an invalid subscription nameis specified.
since:
1.1 |
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