This paper focus on the role of language constructs in the design of
frameworks, with emphasis on support for encapsulation of the stable
part of the design, and on support for capturing its intentions in a
precise and preferably statically checkable way. Framework design is a
balance between flexibility and safety. However, in order for
frameworks to be industrially acceptable, the structural and behavioural
properties of a framework must be enforceable (mostly statically). We
will show that well-known static language constructs offers strong
support for industrial framework design, providing that they are
generalized.