State Abstraction-Based Synchronization

• Synchronization == delay method invocation (like guards).
• Sync. condition == set of abstract states (not like guards), included in method signatures.

  bbuf = interface { full, mid, empty }
    ...
    put = method({empty,mid}b:self...)
    get = method({full,mid}b:self...)
  

• Abstract state conditions are independent of implemetation of objects, thus can be (interface-) inherited freely.