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To communicate events between different agents, you must schedule listeners for the inbound agents on your local system. The Business Event System requires listeners to be scheduled to receive inbound event messages.

When you schedule a listener for an agent, it monitors the agent's queue, dequeuing any inbound event messages. When an event message is received, the Event Manager searches for and executes any active subscriptions by the local system to that event with a source type of External, and also any active subscriptions by the local system to the Any event with a source type of External. The listener exits after all event messages on the agent's queue have been dequeued.

The agent listener program is defined as a service component in the Generic Service Component Framework. This framework helps to simplify and automate the management of background Java services.

You can use Oracle Workflow Manager to submit and manage agent listener service components. Oracle Workflow Manager is available as a component of Oracle Applications Manager if you are using the version of Oracle Workflow embedded in Oracle Applications, or as a component of Oracle Enterprise Manager if you are using the standalone version of Oracle Workflow. For more information, please refer to the Oracle Applications Manager online help or the Oracle Enterprise Manager online help.

Additionally, if you are using the standalone version of Oracle Workflow, you can also use the Check Setup web page to schedule listeners for your local inbound agents. When you schedule a listener through the Check Setup page, Oracle Workflow reruns the listener indefinitely, at the interval you specify. After you schedule a listener, you can modify its schedule by updating its settings. You can also stop a listener altogether by deleting it. See: To Schedule a Listener for a Local Inbound Agent and To Update or Delete a Listener.

Oracle Workflow also provides an administrative script named wfagtlst.sql that you can use to run an agent listener. See Wfagtlst.sql.

Oracle Workflow provides three seeded agent listener service components for the standard WF_DEFERRED, WF_ERROR, and WF_NOTIFICATION_IN agents. These agent listeners are named Workflow Deferred Agent Listener, Workflow Error Agent Listener, and Workflow Inbound Notifications Agent Listener, and they support deferred subscription processing, error handling for the Business Event System, and inbound e-mail processing for notification mailers, respectively.

In Oracle Applications, Oracle XML Gateway also provides two seeded agent listener service components for the standard ECX_INBOUND and ECX_TRANSACTION agents. These agent listeners are named ECX Inbound Agent Listener and ECX Transaction Agent Listener, respectively. For more information, see Starting Agent Listeners, Oracle XML Gateway User's Guide. See: Monitor Workflow Processes, Oracle XML Gateway User's Guide.

You can also optionally create additional agent listener service components. For example, you can configure agent listeners for other inbound agents that you want to use for event message propagation, such as the standard WF_IN and WF_JMS_IN agents, or any custom agents. You can also configure an agent listener service component that only processes messages on a particular agent that are instances of a specific event.

If you create custom agent listener service components, you can assign them to the seeded container for agent listeners. In Oracle Applications, the seeded container is named Workflow Agent Listener Service; in standalone Oracle Workflow, the seeded container is named WFALSNRSVC, within an OC4J instance named Service_Component_Container. In Oracle Applications, based on the volume to be handled by the seeded container, you can also choose to create your own custom containers. You create a container as a GSM service in Oracle Applications Manager. If you create a custom GSM service in OAM, you can copy the service parameters from the seeded Workflow Agent Listener Service to your new service in order to specify how to run the new service.

Before agent listener service components can run, the container which manages them must first be started. In order to run the seeded agent listeners, you should ensure that the Workflow Agent Listener Service container is running using Oracle Applications Manager for the version of Oracle Workflow embedded in Oracle Applications, or ensure that the WFALSNRSVC container is running using Oracle Enterprise Manager for the standalone version of Oracle Workflow. If you create your own custom containers in OAM for custom service components, ensure that those containers are running as well.

See Also

Agents, Oracle Workflow Developer's Guide

Listen, Oracle Workflow API Reference

Wfagtlst.sql

To Schedule a Listener for a Local Inbound Agent

To Update or Delete a Listener

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