A set of criteria is a set of rules that can be used to test a condition. For instance, a set of criteria can be used to select items to go in a list, or items to go on a report, or to validate users' input.
Criteria can simply compare static values or can be complex, combining numerous operators and values. Values can be variable (for example, the current date can be used as a value).
When you recall a set of criteria through the CAS API to perform a test, variable values are supplied by the calling procedure, interactively by the user (through a run-time panel), or by an exit procedure that you define. The criteria exit can process the entries made on a run time panel and also determine whether the panel was actioned or canceled.
You can specify a data source for the set of criteria, which the exit uses to determine how the criteria are processed. You can define exit parameters within the criteria definition for the exit. This lets you change the criteria behavior without having to rewrite the exit procedure and also lets you write a generalized exit that can then be used by other criteria definitions.