The Requirements element
specifies a list of conditions that must be met in order for the task
to run. If the condition is true, SAS code can be generated. If the
condition is false, no code is generated. When defining a requirement,
you can specify the message to display when the requirement is not
met.
The Requirements element
can have multiple Requirement tags. Each Requirement tag
has a condition attribute, which is a conditional
expression that is used to evaluate whether the requirement is met.
The conditional expression that is used is identical to the conditional
expression in Apache Velocity. For more information, see the Apache
Velocity User’s Guide.
Each Requirement tag
also has a Message element, which has no
attributes. The value of this element is the message that is displayed
if the condition is not satisfied.
Because dependencies
can affect the state of the user interface as well as the state of
the Velocity variables, the Requirements element
is evaluated after the Dependencies element.
As a result, any changes due to dependencies are made before determining
whether the requirements are satisfied.