32 Managing Business Events

32.1 Subscribing to Business Events

You can subscribe to business events in Oracle Enterprise Manager Fusion Middleware Control Console. Business events consist of message data sent as the result of an occurrence in a business environment. You create business events in Oracle JDeveloper and include them in SOA composite applications that you deploy to Oracle Enterprise Manager Fusion Middleware Control Console. Service components and database agents can subscribe to business events. Only database agents can be subscribed to from Oracle Enterprise Manager Fusion Middleware Control Console. Service components are only subscribed to from Oracle JDeveloper. When a business event is published, the entity subscribed to that event receives it.

To subscribe to business events:

1. Access this page through one of the following options:

   From the SOA Infrastructure Menu...	From the SOA Folder in the Navigator...
   Select Business Events.	Right-click soa-infra. Select Business Events.

   
   

   The Events page displays the following details:

   • A utility for searching for a specific business event by specifying a full or partial name and clicking the Search icon. Click the Help icon for details.

   • Business events, including the namespace used, event name, number of subscriptions to each event, and number of failed event deliveries. Business events are contained within their namespace.

   
   Description of the illustration busevent_events1.gif
   
   

2. Select a specific event in the Namespaces and Events section.

3. Click Show Event Definition.

   The event definition language (EDL) file for the selected event appears. The business event is defined using EDL. EDL is a schema used to build business event definitions.

   In this example, two business events named OrderReceivedEvent and ProductSoldAlert appear in the event definition. The namespace (orders) and associated schema file (ProductOrder.xsd) are referenced.

   
   Description of the illustration busevent_def.gif
   
   

4. Click OK to close the dialog.

5. Click Subscribe to subscribe a database agent to the event selected in the Namespaces and Events table.

   The Create Database Subscription to an Event dialog appears. You create an agent to listen for and subscribe to appropriate events when they are published.

   
   Description of the illustration busevent_events2.gif
   
   

6. Enter the following values. An asterisk indicates a required field.

   Field	Description
   Event Namespace	Displays the event namespace.
   Event Name	Displays the event name.
   Database Agent	Specify a database agent name or click Create Agent to create an agent. The agent listens for and subscribes to appropriate events when they are published.
   Consistency Level	Select one of the following options: Guaranteed: Delivers events to the subscriber asynchronously without a global transaction. The subscriber can choose to create its own local transaction for processing, but it is committed independently of the rest of the event processing. The event is guaranteed to be handed to the subscriber, but because there is no global transaction, there is a possibility that a system failure can cause an event to be delivered multiple times. If the subscriber throws an exception (or fails in any way), the exception is logged, but the event is not resent. Immediate: Delivers events to the subscriber on the same transaction and same thread as the publisher. The publish call does not return until all immediate subscribers have completed processing. If any subscribers throw an exception, no additional subscribers are invoked and an exception is thrown to the publisher.
   XPath Filter	If you want to filter the event, specify an XPath expression. When the subscription is delivered and the expression logic is satisfied, the event is accepted for delivery. If the logic is not satisfied, the event is not delivered.

   
   

7. Click Subscribe.

8. Click Test to test a selected event. This action enables you to publish a test event that subscribers can act upon.

   The Test Event dialog appears.

9. Specify the XML payload to use in the test.

10. Click Publish.

For more information, see the following documentation:

• Section 1.2.8, "Understanding the Contents of SOA Composite Applications"

• Oracle Fusion Middleware Developer's Guide for Oracle SOA Suite for details about business events

32.2 Managing Business Event Subscribers

You can also create, edit, and delete existing database subscriptions. When a business event is published, service components and database agents can subscribe to it. Use this page to view all subscriptions to business events. This page also enables you to manage event subscriptions by database agents. Service component subscriptions are created in Oracle JDeveloper during design time and cannot be modified in Oracle Enterprise Manager Fusion Middleware Control Console.

To manage business event subscribers:

1. Access this page through one of the following options:

   From the SOA Infrastructure Menu...	From the SOA Folder in the Navigator...
   Select Business Events.	Right-click soa-infra. Select Business Events.

   
   

2. Click Subscriptions.

   The Subscriptions page displays the following details:

   • A utility for searching for a specific subscription by specifying a criteria and clicking Search. Click the Help icon for details.

   • The database subscriptions, including the event name, namespace used, subscription agent name, optionally defined XPath filters, consistency level, and number of failed deliveries. You create database subscriptions to business events in this page during run time.

   • The component subscriptions, including the event name, namespace used, the service component subscribing to the event, the SOA composite application, optionally defined XPath filters, and the consistency level.

   
   Description of the illustration busevent_subscribers.gif
   
   

3. Click the appropriate icon below the Database Subscriptions title to create, edit, or delete a database subscription.

   
   Description of the illustration busevent_events3.gif
   
   

4. Click Manage Database Agents to edit the PL/SQL procedure or delete agents not currently subscribing to events.

5. In the Subscription Component column, click a service component to access its home page.

6. In the Composite column, click a SOA composite application to access its home page.

For more information, see the following documentation:

• Section 32.1, "Subscribing to Business Events" for instructions on creating a database subscription

• Oracle Fusion Middleware Developer's Guide for Oracle SOA Suite for details about business events

32.3 Recovering from Business Event Faults

You can recover from business event faults that are identified as recoverable.

To recover from business event faults:

1. Access this page through one of the following options:

   From the SOA Infrastructure Menu...	From the SOA Folder in the Navigator...
   Select Business Events.	Right-click soa-infra. Select Business Events.

   
   

2. Click Faults.

   The Faults page displays the following details:

   • A utility for searching for a specific business event fault by specifying a criteria and clicking Search.

   • Faults occurring in a business event, including the error message, whether you can recover from the fault, the time at which the fault occurred, the event namespace, event name, the subscriber, and the event type (database or Java). The Recoverable? column identifies faults for which recovery actions can be performed.

   
   Description of the illustration busevent_faults.gif
   
   

3. From the View list, select Columns > Fault ID to display the fault IDs for each error message.

4. Click a specific fault that has been identified as recoverable and select one of the following options:

   Action	Description
   Retry	Retries the instance in which the fault occurred.
   Abort	Aborts the entire instance in which the fault occurred.

   
   

5. In the Logs column, click a specific log to access the Log Messages page with filtered messages specific to that instance.

For more information about business events, see Oracle Fusion Middleware Developer's Guide for Oracle SOA Suite.