As
an example of using properties in a plug-in, this section describes the implementation of a
security level plug-in. Property associations are used to assign a security level
to each
component in a specification. We declare a new SecurityLevel property for this purpose.
This analysis can be applied after assigning a security level to each component in a
specification. The analysis checks that a component only contains components whose security
level is less than its own, and that connections only flow from lower level components to higher
level components. In addition, the analysis will infer the least upper bound on the security level
necessary for components not explicitly given a security level.