IBM Tivoli NetView for z/OS Programming: Pipes - IBM notice

Complex Pipelines
Chapter 2, “Pipeline Stages and Syntax,” on page 19 describes each NetView
pipeline stage.
Some stages accept multiple input streams and others generate multiple output
streams.
An example of a stage that generates multiple output streams is the LOCATE stage
as shown in Figure 3 on page 3 and Figure 6 on page 4.
LOCATE is used to select specific data from the input stream. In both examples,
only the input data, including the string BOB, flow through the stage. But, what if
you wanted a way to act on both the selected data and the data that was not
selected? You really want a pipeline that looks something like that shown in
Figure 9.
Bob Smith
Fred Ford
Mary Bobbit
Figure 9. Complex Pipeline
Locate /Bob/
Stage
Bob Smith
Mary Bobbit
Fred Ford
Introduction and Concepts
Output selected
by Locate
Output not selected
by Locate
The pipeline shown in Figure 9 is called a complex pipeline. A complex pipeline is
made up of simple pipelines connected with labels, such as the one shown in
Figure 6 on page 4. Complex pipelines are simple programs rather than
complicated commands.
Creating a Complex Pipeline
This section describes the way to create a complex pipeline using stages with
multiple inputs and outputs. When stages are adjacent to each other in a pipeline,
the output stream of a stage is connected to the input stream of the stage that
follows.
Use a label to connect the streams of stages that are not adjacent. A label is 1–8
alphanumeric characters followed by a colon. For example, the B in the following
example is a label:
...|B: LOCATE /X/|...
To use multiple streams, first include the label on the stage that results in multiple
output streams. This first label defines or declares the label. Then, place a matching
label in the pipeline specification as if it were a stage. The stages following the
label will act on the data passed as the primary output of the stage defining the
label. The label acts as a connector and provides the input stream to the
subsequent pipeline stages, for example:
Chapter 1. NetView Pipelines Introduction and General Concepts 7