An Object Constraint Language (OCL) resource is a text file that
stores OCL statements, which are the queries that you write to explore characteristics
of UML model elements. To parse or evaluate an OCL statement, you must store
it in an OCL resource.
An OCL resource can contain several OCL statements, but the editor can
only parse or evaluate one OCL statement at a time.
You must save all OCL resources with a file name extension of .ocl.