About the Requirements Element

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.