The XASession interface extends the capability of
Session by adding access to a JMS provider's support for the
Java Transaction API (JTA) (optional). This support takes the form of a
javax.transaction.xa.XAResource object. The functionality of
this object closely resembles that defined by the standard X/Open XA
Resource interface.
An application server controls the transactional assignment of an
XASession by obtaining its XAResource. It uses
the XAResource to assign the session to a transaction, prepare
and commit work on the transaction, and so on.
An XAResource provides some fairly sophisticated facilities
for interleaving work on multiple transactions, recovering a list of
transactions in progress, and so on. A JTA aware JMS provider must fully
implement this functionality. This could be done by using the services
of a database that supports XA, or a JMS provider may choose to implement
this functionality from scratch.
A client of the application server is given what it thinks is a
regular JMS Session. Behind the scenes, the application server
controls the transaction management of the underlying
XASession.
The XASession interface is optional. JMS providers
are not required to support this interface. This interface is for
use by JMS providers to support transactional environments.
Client programs are strongly encouraged to use the transactional support
available in their environment, rather than use these XA
interfaces directly. | 