Event Task
We can define events in the workflow to specify the
sequence of task execution. The event is triggered based on the completion of
the sequence of tasks.
- Event-Raise task. Event-Raise task represents a user-defined event. When the Integration Service runs the Event-Raise task, the Event-Raise task triggers the event. Use the Event-Raise task with the Event-Wait task to define events.
- Event-Wait task. The Event-Wait task waits for an event to occur. Once the event triggers, the Integration Service continues executing the rest of the workflow.
To coordinate the execution of the workflow, you may specify the following
types of events for the Event-Wait and Event-Raise tasks:
- Predefined event. A predefined event is a file-watch event. The predefined events, use an Event-Wait task to instruct the Integration Service to wait for the specified indicator file to appear before continuing with the rest of the workflow. When the Integration Service locates the indicator file, it starts the next task in the workflow.
- User-defined event. A user-defined event is a sequence of tasks in the workflow. Use an Event-Raise task to specify the location of the user-defined event in the workflow. A user-defined event is sequence of tasks in the branch from the Start task leading to the Event-Raise task.
When all the tasks in the branch from
the Start task to the Event-Raise task complete, the Event-Raise task triggers
the event. The Event-Wait task waits for the Event-Raise task to trigger the
event before continuing with the rest of the tasks in its branch.
Event-Raise Tasks
The Event-Raise task represents the location of a
user-defined event. A user-defined event is the sequence of tasks in the branch
from the Start task to the Event-Raise task. When the Integration Service runs
the Event-Raise task, the Event-Raise task triggers the user-defined event.
To use an Event-Raise task, you must first declare the
user-defined event. Then, create an Event-Raise task in the workflow to
represent the location of the user-defined event you just declared. In the
Event-Raise task properties, specify the name of a user-defined event.
Event-Wait Tasks
The Event-Wait task waits for a predefined event or a
user-defined event. A predefined event is a file-watch event. When you use the
Event-Wait task to wait for a predefined event, you specify an indicator file
for the Integration Service to watch. The Integration Service waits for the
indicator file to appear. Once the indicator file appears, the Integration
Service continues running tasks after the Event-Wait task.
You can assign resources to Event-Wait tasks that wait
for predefined events. You may want to assign a resource to a predefined
Event-Wait task if you are running on a grid and the indicator file appears on
a specific node or in a specific directory. When you assign a resource to a
predefined Event-Wait task and the Integration Service is configured to check
resources, the Load Balancer distributes the task to a node where the required
resource is available.
Note: If you use the Event-Raise task to trigger the
event when you wait for a predefined event, you may not be able to successfully
recover the workflow.
You can also use the Event-Wait task to wait for a user-defined event. To
use the Event-Wait task for a user-defined event, specify the name of the
user-defined event in the Event-Wait task properties. The Integration Service
waits for the Event-Raise task to trigger the user-defined event. Once the
user-defined event is triggered, the Integration Service continues running
tasks after the Event-Wait task.
Event Wait: Please click on this link
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