On State Classes and Their Dynamic Semantics

We introduce "state classes", a construct to program objects that can be safely concurrently accessed. State classes model the notion of object's state (intended as some abstraction over the value of fields) that plays a key role in concurrent object-oriented programming (as the state of an object changes, so does its coordination behavior). We show how state classes can be added to Java-like languages by presenting StateJ, an extension of Java with state classes. The operational semantics of the state class construct is illustrated both at an abstract level, by means of a core calculus for StateJ, and at a concrete level, by defining a translation from StateJ into Java.