web server - Borland Technical Publications

JMS and Transactions
and its accompanying Borland descriptor application-client-borland.xml:
JMS and Transactions
...
jms/MyJMSTopicConnectionFactory
resources/tcf
jms/MyJMSTopic
resources/t
...
Now let's see how we obtain object references to a JMS connection factory and a
destination in the application logic. In retrieval of the connection factory, the application
performs a JNDI lookup of the value from element in the
J2EE deployment descriptor. To retrieve the destination object, a JNDI lookup is
performed against the value of element in the
J2EE deployment descriptor. The names specified for are identical to JNDI
names in elements of the JMS resource definitions in a deployed DAR
module. When a lookup succeeds a JMS resource object is obtained, that is, for JMS
connection factory identified through logical name jms/MyJMSTopicConnectionFactory a
deployed JMS definition object is retrieved from the Naming Service under resources/
tcf and from it a connection factory object is created and returned to the application.
For example, the application client code associated with client descriptors provided
above resolves JMS resource objects as follows:
javax.jms.TopicConnectionFactory myTCF;
javax.jms.Topic myTopic;
try {
javax.naming.Context ctx = (javax.naming.Context) new
javax.naming.InitialContext();
myTCF = (TopicConnectionFactory) ctx.lookup("java:comp/env/jms/
MyJMSTopicConnectionFactory");
// Now ready to obtain a connection from myTCF
myTopic = (Topic) ctx.lookup("java:comp/env/jms/MyJMSTopic");
...
}
catch (javax.naming.NamingException exp) {
exp.printStackTrace();
}
The rules for using JMS APIs in EJB bean code with transactions are discussed in the
EJB 2.0 specification section 17.3.5.
Following is an extract:
17.3.5 Use of JMS APIs in transactions
The Bean Provider must not make use of the JMS request/reply paradigm (sending of a
JMS message, followed by the synchronous receipt of a reply to that message) within
a single transaction.
Because a JMS message is not delivered to its final destination until the
transaction commits, the receipt of the reply within the same transaction will
never take place. Because the container manages the transactional enlistment of JMS
216 BES Developer’s Guide