org.apache.nifi.annotation.behavior

Annotation Type TriggerWhenEmpty

@Documented
 @Target(value=TYPE)
 @Retention(value=RUNTIME)
 @Inherited
public @interface TriggerWhenEmpty

Marker annotation a Processor implementation can use to indicate that the Processor should still be triggered even when it has no data in its work queue.

A Processor is scheduled to be triggered based on its configured Scheduling Period and Scheduling Strategy. However, when the scheduling period elapses, the Processor will not be scheduled if it has no work to do. Normally, a Processor is said to have work to do if one of the following circumstances is true:

• An incoming Connection has data in its queue
• The Processor has no incoming Connections.
• All incoming Connections are self-loops (both the source and destination of the Connection are the same Processor).

If the Processor needs to be triggered to run even when the above conditions are all false, the Processor's class can be annotated with this annotation, which will cause the Processor to be triggered, even if its incoming queues are empty.