IBM Streams 4.3.0

Annotations

Operators can be annotated. Annotations influence the run time behavior of stream processing applications.

Annotations are identified by a keyword beginning with the @ symbol. They consist of a set of zero or more parameter name and value pairs in parentheses. The valid parameter names are determined by the specific annotation. Likewise, the valid parameter values are specific to an annotation and parameter. The parameter list can occur in any order in the annotation.

Autonomous annotation
The SPL annotation @autonomous defines autonomous regions and can be applied to an operator or operators in an application graph to remove those operators from a consistent region.
Catch annotation
The SPL annotation @catch indicates that exceptions of a specified type that are thrown by an operator while processing tuples are caught.
Consistent annotation
The SPL annotation @consistent that defines consistent regions can be configured according to how and when the regions are drained, and the maximum amount of time that a region is allotted for a drain or reset process to complete.
EventTime annotation
The SPL annotation @eventTime specifies that all the output ports of operators where the annotation is in effect emit a stream with event-time values and watermarks. An event-time graph starts from the output port of an event-time source operator. The event-time source operator inserts watermarks into the output stream from time to time.
Parallel annotation
To take advantage of data-parallelism, apply the @parallelannotation to invocations of primitive or composite operators. Data-parallelism means replicating copies of operators and splitting streams so that different tuples go to each set of replicas.
Threading annotation
The SPL @threading annotation determines the threading model to use for the operators inside of a composite operator.
View annotation
The SPL annotation @view specifies that a view is to be created when the streams processing application is run.

Parent topic: Streams Processing Language (SPL) reference