Example 1: Handling a planned outage of an MDB application external resource

You can configure the system so that, if there is a problem with a dependent external system resource, the enterprise or business-level application can continue.

Before you begin

During the time that the system resource is unavailable, there must be no exceptions in the enterprise or business-level application, or messages on the exception destination that must be resolved later.

About this task

Add a maintenance level to an external system resource that is used by the deployed message-driven bean (MDB) of one of the enterprise or business-level applications. The act of applying the maintenance level requires the system resource (for example, a database) to be unavailable for about five minutes.

The JCA MBean emits JMX notifications to indicate that the MDB is paused, and that the MDB has resumed. Consider registering a message listener on the JCA MBean to receive the JMX notifications.

Procedure

  1. Navigate to the deployed enterprise application that contains the MDB.
  2. From the MDB, navigate to its JMS activation specification. Click Resources -> JMS -> Activation specifications -> activation_specification_name and click Pause on the administrative panel for the MDB.
  3. When you receive a JMX notification and a log entry indicating that the MDB is paused, stop the database and apply the maintenance level. While the MDB is paused, no messages are sent to the exception destination and no error messages appear in the console related to the stopped database.
  4. Restart the database and test that it is working as expected.
  5. Log on to the administrative console again, navigate to the same enterprise or business-level application and click Resume on the administrative panel for the MDB. You can also resume the MDB by using scripting and the JCA MBean. The initial JMX notification and log entry indicate which MBean to use to resume the MDB. The MDB begins to be driven with the messages that are on the destination.

Results

You have paused and resumed an application while an external resource that it uses is not available for a short time.

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Timestamp icon Last updated: March 5, 2017 17:27
File name: tjn_mdb_0001_Ex1.html