ViewPoint Manual

Functional Description
ViewPoint Manual—426801-001
5-24
Event Filters
Event Filters
Each filter is contained in a separate filter object file. For primary-events displays, these
files are kept in the ViewPoint program subvolume. One filter is loaded at startup time,
and it cannot be changed until the ViewPoint TCP is stopped and restarted. This filter is
common to all operators logged on at a given NCN.
For alternate-events displays, you, as one of several operators using the same ViewPoint
system, can compile your own filters, store them in your own subvolume, and load any
one filter at any time. You can also pass parameters from the Alternate Event
Configuration screen to the currently loaded filter for dynamic filter definition.
When an event distributor receives an event message, it compares the token codes and
other information contained in the message with token codes and other information
specified in the currently loaded filter. If there is a match, the message is passed on to
the next process in the event-handling chain; otherwise, it is not passed on (although it
continues to exist in the event log).
Loading a filter consists of copying it from its disk file to the data space of an event
distributor process. This makes the filter available to the filter comparison logic of the
process.
Filters are stored in filter files by the event-management filter compiler, one filter per
file. This is described in the EMS Manual.
Event Distributors
Figure 5-18 illustrates the three ways in which event distributors access the collector’s
current log set. These three ways are numbered 1, 2, and 3 in the figure. Note that there
are two event distributors: primary-events distributor and alternate-events distributor.
Both are shown to be reading from the current log file set, and both send their filtered
messages to an event collection server.