Event wait and Event Raise tasks in informatica

There are different types of tasks in Informatica Workflow manager which we use while running a workflow.
I have listed it below. 

Tasks	Description
Assignment	Used to assign a value to a workflow variable
Command	Used to run a shell command during the workflow
Control	Used to stop or abort the workflow
Decision	Tells a condition to evaluate
Email	Used to send email during the workflow
Event-Raise	Notifies the Event-Wait task that an event has occurred
Event-Wait	It waits for the event to completed in order to start the next task
Session	Used to run the mapping created in Designer buy linking to session
Timer	It waits for a already timed event to start

WORKING WITH EVENT TASKS

We can define events in the workflow to specify the sequence of task execution.

Use the following tasks to use events in the workflow:

v    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.

Types of Events:

·        Pre-defined event: A pre-defined event is a file-watch event. This event waits for a specified file to arrive at a given location or directory.

Let us try to understand it with an example. Suppose you wanted to wait for a file to arrive in a directory while keeping the workflow on running mode. Once the file arrives in the directory the mapping session should automatically be kicked off to load the data into target. In this case we can use event wait task as file watcher event. PFB screenshot of the same.

·        User-defined event: A user-defined event is a sequence of tasks in the Workflow. We create events and then raise them as per need. In this case we first raise a user defined event and then configure the event wait which will wait for user defined event to occur and triggers the next session in the workflow

    EVENT RAISE: Event-Raise task represents a user-defined event. We use this task to raise a user defined event.

    EVENT WAIT: Event-Wait task waits for a file watcher event or user defined event to occur before executing the next session in the workflow.