Administering listener ports and activation specifications for message-driven beans

Use these tasks to manage the listener ports and activation specifications used by message-driven beans (MDBs). These tasks are supplementary to the tasks of administering resource adapters, and JMS provider resources.

Overview

• J2C activation specifications for JCA 1.5-compliant message-driven beans. Activation specifications must be provided when the application's resources are configured using the default messaging provider or any generic J2C Resource Adapter that supports inbound messaging.

• The message listener service, listener ports, and listeners for EJB 2.0 message-driven beans deployed against listener ports. Listener ports must be provided when using the JMS providers: V5 Default Messaging, WebSphere MQ, or Generic.

Listener port or activation specification?

WebSphere Application Server v6 supports the enhancements made to the EJB 2.1 and J2EE 1.4 specifications which allow any resource that has a JCA 1.5 adapter to trigger an MDB (formerly only JMS resources could trigger MDBs). WebSphere Application Server v5 and EJB 2.0 used the listener port which specified a JMS connection factory and a destination. This allowed a pool of MDB instances to connect to the messaging system and listen to the designated destination. EJB 2.1 specifies an additional requirement of an MDB working with a JCA adapter using an activation specification. If you are developing WebSphere Application Server v6 applications, you should consider the following questions:

• Should I use a listener port or an activation specification?

• Should I convert my existing listener ports to activation specifications?

• Will listener ports eventually not be supported anymore?

Here are some guidelines to help you decide:

• If you are using J2EE 1.2 and EJB 1.1 with WebSphere Application Server v4, MDBs are not used, so you do not have to make a decision. WebSphere Application Server v4 uses message beans, but these are not MDbs or EJBs.

• If you are using J2EE 1.3 and EJB 2.0 with WebSphere Application Server v5, use listener ports. The MDBs are JMS MDBs that implement MessageListener, and there is no JCA support. WebSphere Application Server v5 uses listener ;ports to associate MDB classes with their JMS destinations.

• If you are using J2EE 1.4 and EJB 2.1 with WebSphere Application Server v6, use activation specifications. A connector MDB uses JCA to access its resources, so the connector must therefore be configured with an activation specification. This is for new bean development, and does not affect the conversion of MDBs from EJB 2.0 to EJB 2.1.

• If you are using J2EE 1.4 and EJB 2.1 with WebSphere Application Server v6, the decision depends on whether your JMS provider API is implemented with JCA. In J2EE 1.4, the JMS 1.1 API can now be implemented with the JCA 1.5 API. If so, your MDB is a JMS MDB that is implemented as a connector MDB, and must therefore be configured with an activation specification. If not, this is the same JMS situation as for J2EE 1.3, and configure this EJB 2.1 MDB in the same way as you would configure an EJB 2.0 MDB, which in WebSphere Application Server is to use a listener port.

To summarize: in WebSphere Application Server v6, the decision on whether or not to use a listener port or an activation specification depends on the following scenarios:

• whether you upgrade your EJB 2.0 MDBs to EJB 2.1

• whether you want your EJB 2.1 MDB to use a JCA adapter

• whether you access your JMS provider via a JCA adapter.

If you have JMS API implementations that do not use JCA, WebSphere Application Server requires listener ports; if all JMS API implementations use JCA, listener ports are no longer required.

You can update the configuration data at any time, but some updates only take effect when the appropriate server is next started.

For additional information about administering support for message-driven beans, see the following topics:

Procedure

• Configuring a JMS activation specification for MDBs used by the default messaging provider

• Configuring a J2C activation specification

• Configuring a J2C administered object

• Configuring message listener resources for EJB 2.0 message-driven beans

Related tasks