Guidelines, related to versions of WebSphere® Application Server, to help you choose
when to configure your message-driven beans to work with listener
ports rather than activation specifications.
You can configure the following resources for message-driven beans:
- Activation specifications for message-driven beans that comply
with Java EE Connector Architecture (JCA) Version
1.5.
- The message listener service, listener ports, and listeners for
any message-driven beans that you want to deploy against listener
ports.
Activation specifications supersede the use of
listener ports, which became a stabilized function in
WebSphere Application Server version 7.0 (for
more information, see
Stabilized features). There
are several advantages to using activation specifications over listener
ports:
- Activation specifications are simple to configure, because they
only require two objects: the activation specification and a message
destination. Listener ports require three objects: a connection factory,
a message destination, and the message listener port itself.
- Activation specifications are not limited to server scope. They
can be defined at any administrative scope in WebSphere Application Server. Message listener
ports must be configured at server scope. This means that each server
in a node requires its own listener port. For example, if a node is
made up of three servers, three separate listener ports must be configured.
Activation specifications can be configured at node scope, so in the
example only one activation specification would be needed.
- Activation specifications are part of the Java Platform, Enterprise Edition Connector
Architecture 1.5 standards specification (JCA 1.5). Listener port
support in WebSphere Application
Server makes use of the application server facilities interfaces defined
in the JMS specification, but is not part of any specification itself.
For WebSphere Application Server Version 7 and later, listener ports are stabilized. For more information, read the article on stabilized features. You should plan to migrate your WebSphere MQ message-driven bean deployment configurations from using listener ports to using activation specifications. However, you should not begin this migration until you are sure the application does not have to work on application servers earlier than WebSphere Application Server Version 7. For example, if you have an application server cluster with some members at Version 6.1 and some at Version 7, you should not migrate applications on that cluster to use activation specifications until after you migrate all the application servers in the cluster to Version 7. Also, when you migrate to activation specifications on the z/OS® platform, you must enable the Control Region Adjunct (CRA) process of the application server (by using either the WebSphere MQ CRA settings panel or the manageWMQ command to include starting the CRA process as part of starting an application server).
If you want to use message-driven beans with a messaging provider that does not have a JCA 1.5 resource adapter, you cannot use activation specifications and therefore you must configure your beans against a listener port. There are also a few scenarios in which, although you could use activation specifications, you might still choose to use listener ports. For example, for compatibility with existing message-driven bean applications. Here
are some guidelines, related to versions of WebSphere Application Server, to help you choose
when to use listener ports rather than activation specifications:
- WebSphere Application Server Version
4 does not support message-driven beans, so listener ports and activation
specifications are not applicable. WebSphere Application Server Version 4 does
support message beans, but these are not message-driven beans.
- WebSphere Application Server Version
5 supports EJB 2.0 (JMS only) message-driven beans that are deployed
using listener ports. This deployment technology is sometimes called
application server facility (ASF).
- WebSphere Application Server Version 6 continues
to support message-driven beans that are deployed to use listener
ports, and also supports JCA, which you can use to deploy message-driven
beans that use activation specifications. This gives you the following
options for deploying message-driven beans on WebSphere Application Server Version 6:
- You must deploy default messaging (service integration bus) message-driven
beans to use activation specifications.
- You must deploy WebSphere MQ message-driven beans to use listener
ports.
- You can deploy third-party messaging message-driven beans to use
either listener ports or activation specifications, depending on the
facilities available from your third-party messaging provider.
- WebSphere Application Server Version
7 continues to support the same options for message-driven bean deployment
that WebSphere Application Server Version
6 supports, and adds a new option for WebSphere MQ message-driven
beans. This gives you the following options for deploying message-driven
beans on WebSphere Application Server Version
7:
- You must deploy default messaging (service integration bus) message-driven
beans to use activation specifications.
- You can deploy new and existing WebSphere MQ message-driven beans
to use listener ports (as on WebSphere Application Server Version 6) or
to use activation specifications.
- You can deploy third-party messaging message-driven beans to use
either listener ports or activation specifications, depending on the
facilities available from your third-party messaging provider.
To assist in migrating listener ports to activation
specifications, the WebSphere Application Server administrative
console provides a Convert listener port to activation
specification wizard on the Message listener port collection
panel. This allows you to convert existing listener ports into activation
specifications. However, this function only creates a new activation
specification with the same configuration used by the listener port.
It does not modify application deployments to use the newly created
activation specification.