This chapter describes how to filter mainframe messages at the SNA View workstation, and contains the following sections:
For information about how to access the Filters window and enter the commands described in this chapter, see the section "Viewing VTAM and MVS Messages" in the "Using the SNA View Workstation Application" chapter.
This section explains how SNA View, at the mainframe and at the workstation, passes some mainframe messages to the workstation while filtering out other mainframe messages. SNA View lets you define message filters, for VTAM and MVS mainframe messages, at the following levels:
Table 5-1 shows how, on the mainframe, VTAM and MVS messages can be passed from the mainframe to the workstation. The Filtering Statement column shows what happens when you use filtering commands and parameter cards.
The MESSAGES VTAM command sends only VTAM messages to the workstation; the MVS messages are blocked.
The two FILTER parameter cards specify those VTAM messages that will be sent to the workstation; all others will be blocked.
|Messages Passed Through
| Parameter Card:
|This MESSAGES parameter card lets only VTAM messages through to the workstation. It filters out all MVS messages.
|All VTAM messages
| Parameter Card:
FILTER IST111I IST222I IST333I IST444I
|This FILTER parameter card lets through just the VTAM messages IST111I, IST222I, IST333I, and IST444I. It filters out all other VTAM messages.
FILTER ADD IST555I
|This FILTER ADD command adds IST555I to the message filter, letting it pass to the workstation.
Table 5-2 shows how, at the workstation, you can filter messages that come from the mainframe. Using the message filtering statements, you can specify the messages that will be displayed for the workstation user. In the Filtering Statement column, the message filtering statements beginning with the letter "I" specify those messages that are included for display; the filtering statements that begin with the letter "X" specify messages that are excluded from the display.
|Messages Passed Through
| Server Filter table entry:
I IST111I 1 OR IST222I 1 OR IST555I 1
|This entry in the VTAM message filter table, $SVHOME/PARM/svvtamsysfilter.tbl, includes messages IST111I, IST222I, and IST555I.
| Client Message window:
X IST111I 1
|The user at the client enters these filter statements in the VTAM Messages window to exclude message IST111I, and, by default, to include all other messages passed from the server (which are IST222I and IST555I).
The SNA View workstation maintains separate message filters for MVS and VTAM messages. Each message filter is a set of filter statements. Each filter statement is a rule that determines whether a particular message can be displayed at the workstation.
The SNA View workstation message server uses a permanent message filter file to determine which mainframe messages to pass to clients. You can use a text editor to add, delete, or change filter statements in MVS and VTAM filter files. Filters remain in these filter files until you delete or change them. SNA View provides you with two default system filter files. You can add, change, and delete the filter statements in the following files:
The SNA View workstation message clients use temporary message filters that exist only while the client is active. You can use the SNA View Task Manager to enter filter statements into a temporary message filter. When you activate the VTAM or MVS Message Clients, select Filter>Add Filter to add new filter statements. Filter statements entered in this way are placed in a temporary message filter and exist only until you stop the message client.
This section describes how to write message filter statements for use in either the server's message files or the client's message window. Each message filter contains a series of filter statements. Each filter statement defines a rule by which a specific MVS or VTAM message will pass through the filter or be blocked by the filter. There are two kinds of filter statements: default filter statements and user-defined filter statements.
The default filter statement defines what happens to all messages that do not satisfy any of the conditions defined by the user-defined filter statements. The default filter statement is explained in the section "Writing the Default Filter Statement."
A series of user-defined filter statements define conditions for filtering messages out or letting messages through, based on tokens in the messages content. User-defined filter statements are explained in the section "Writing User-Defined Filter Statements."
A default filter statement defines what will happen to all the MVS and VTAM messages that are not specifically included or excluded by the user-defined filter statements. Each filter file can have one and only one default filter statement.
|Filter Statement Syntax:
| Syntax Description:
Specifies the filtering action performed by this filter statement. An action can be one of the following:
|Identifies this as the default statement in a filter table
Example: To exclude all messages that are not specifically included or excluded by a user-defined filter statement, enter this filter statement:
Each user-defined filter statement defines a condition, based on the presence or absence of a message token, by which a message is either included (passed through the filter) or excluded (filtered out). A user-defined filter statement has the following syntax.
| Specifies the filtering action performed by this filter statement. An action can be one of the following:
X = Exclude all messages that contain the specified token in the specified token position
I = Include all messages that contain the specified token in the specified token position
| Token1 Position1
| Identifies a pair of values defined as follows:
Token--a character string contained in the message to be included or excluded
Position--the relative position, in the message, where the Token must be to satisfy the filter statement.
You can include up to 19 pairs of Token and Position values in one filter statement.
| Specifies whether adjacent pairs of Token and Position values are to be ANDed or ORed to satisfy the filter statement. For example, if a filter statement contains these pairs of values:
I IST111I 1 OR IST222I 1
Any message that contains either IST111I or IST222I in the first token position is displayed.
If a filter statement contains these pairs of values:
I IST111I 1 AND IBUPC1 2
Any message that contains the message ID IST111I in the first token position and node name IBUPC1 in the second token position is displayed.
Example: To allow messages IST105I and IST999I to be received, enter this filter statement:
I IST105I 1 OR IST999I 1
I is the filter action, in this case Include.
IST105I is the first token, in this case a VTAM message ID.
1 is the first token's position in the message, in this case position 1.
IST999I is the second token.
1 is the second token's position in the message.
A filter token is a continuous string of alphanumeric characters, with no spaces, that can occur in a VTAM or MVS message. A VTAM or MVS message contains a series of tokens delimited by spaces. A typical VTAM message displayed by SNA View contains a time stamp, followed by the actual message. (The time stamp is not part of the message; it is added by SNA View.) Here is a sample VTAM message:
Mon Mar 27 10:09:52 1996 IST105I NT555 NODE NOW INACTIVE
The VTAM message contains, after the SNA View time stamp, these five tokens:
The first token position after the time stamp is always the message ID (for example, IST105I). SNA View lets you filter on any token in a message. The token position is a number that refers to the position within a VTAM or MVS message where the specific token is displayed.
This Include filter statement for VTAM messages specifies that any VTAM message with the token IST105I in position 1 is to be included (passed through the filter):
I IST105I 1
If you combine this sample filter statement with a default filter statement that excludes all other messages, the system filter table file would contain these filter statements:
I IST105I 1
If these filter statements existed when the VTAM server was started, only VTAM messages with message ID IST105I (indicating nodes going inactive) would be passed through the system filter and forwarded to clients. If you wanted clients to receive all VTAM messages indicating an SNA node going into an active state, you could modify the svvtamsysfilter.tbl file to contain the following entries:
I IST105I 1
I IST093I 1
If you want clients to receive all VTAM messages except for IST105I and IST093I messages, you would modify the system filter table parameter file to contain the following entries:
X IST105I 1
X IST093I 1
When defining a filter table, you are not limited to the MVS or VTAM message ID (which is always token position 1). Although the MVS or VTAM message ID is probably the most useful token, you can specify any token position in the message. If you wanted to receive only messages pertaining to specific resources, you could modify the filter table file to contain filter statements that include only messages that contain the names of those resources.
For example, suppose you wanted to receive only those VTAM messages that contain the SNA resource name SNARSC1 or SNARSC2. Further, suppose you know that, in VTAM messages, the resource names always occur in positions 2, 3, or 4. If you define the following filter statements, you will receive just the VTAM messages that contain SNARSC1 or SNARSC2 in token position 2, 3, or 4. All other messages are excluded by the default filter statement.
I SNARSC1 2
I SNARSC1 3
I SNARSC1 4
I SNARSC2 2
I SNARSC2 3
I SNARSC2 4