Crista proposes the following approach to synchronization in Demeter/Java:

We want to synchronize on entire traversals, pieces of a traversal
and before/after/around methods.

The strategy is to use selfex and mutex but to allow more complex
objects than only qualified method names.

Examples:
(t is a traversal)

selfex {C.t}: no other thread can start the same traversal.

mutex{A.t1(X,Y), A.t2(X,Y), A.t3(X,Y)) the traversals t1, t2 and t3
  are mutually exclusive at classes X and Y only.

mutex{A.t1(strategy s1), A.t2(strategy s1)} the traversals t1 and t2
are mutually exclusive at classes defined by strategy s1.

How does this look?

-- Karl