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

NetView Pipeline Filters
312 Programming: Pipes
5. CORRWAIT is also terminated, because of the termination of TAKE. Therefore,
messages from the display command are no longer read into the pipeline.
6. The CONSOLE stage reads the messages and displays them.
Example 2: Keeping the Last two Messages in the Pipeline
This example shows how to use the TAKE stage to select the last two messages
resulting from a command. This is similar to the previous example; however, the
MLWTO has been split into single-line messages using the SEPARATE command
and the TAKE command is selecting the last messages rather than the first:
PIPE NETVIEW D NET,CDRMS | CORRWAIT 60 | SEPARATE | TAKE LAST 2
| CONSOLE
Output from the pipeline looks similar to:
NCCF NETVIEW CNM01 OPER5 03/20/10 12:00:10
* CNM01 PIPE NETVIEW D NET,CDRMS | CORRWAIT 60 | SEPARATE | TAKE LAST 2 |
CONSOLE
’ CNM01 IST482I B20M NEVAC, SA N/A, EL N/A, NETID = NETD
’ CNM01 IST314I END
Processing steps:
1. The NETVIEW stage executes the DISPLAY command and writes messages to
the output stream.
2. The CORRWAIT stage allows a 60 second wait for each message to be returned
from VTAM. When the CORRWAIT timer expires, further messages generated
by the NETVIEW stage are not accepted into the pipeline.
3. Before the 60 seconds expire, the message DISPLAY ACCEPTED arrives in the
input stream, is read by SEPARATE, and passed as is to the output stream.
The timer is reset.
4. Again, before the 60 seconds expire, the MLWTO is passed to SEPARATE and
because it is an MLWTO, it is split into single-lines, then passed to the output
stream.
5. The stream is passed to TAKE, which selects the last 2 messages and discards
the others.
6. CORRWAIT waits the full 60 seconds, because TAKE LAST is not considered a
terminating stage condition.
7. The CONSOLE stage reads the messages and displays them.
Discarding the First or Last n Messages: DROP
Example: Discarding the First Two Messages
This example shows how to use the DROP stage to discard the first two messages
output from a command. The example shown contains a REXX command list
named DROP2:
/* REXX COMMAND LIST - DROP2 */
’PIPE NETVIEW MAJNODES’, /* ISSUE COMMAND */
’| CORRWAIT 10’, /* WAIT 10 SECONDS */
’| DROP FIRST 2’, /* DROP FIRST 2 MSGS. */
’| CONSOLE’ /* DISPLAY PIPE CONTENTS */
SAY ’RETURN CODE IS’ RC
EXIT
/* DISPLAY RETURN CODE */
Output from DROP2 looks similar to: