Toward constraint-object-oriented development

In this paper, we propose to conservatively extend object-oriented decomposition by letting it affect also operations (methods). Different objects may support different parts of the same operation. The responsibility of defining an operation, in terms of enabling conditions and effects on the state, is distributed over several interacting objects, which act as constraints and express different, partial views about the system behavior. Constraint-oriented reasoning has already been explored and applied in the context of formal specification languages for concurrent and reactive systems, and is sufficiently different from object-oriented reasoning to be considered as a paradigm in itself, with its own specific advantages. Nevertheless, the paper shows that the two approaches are sufficiently compatible to be profitably integrated. We introduce a constraint-oriented style for an object-oriented programming language (JAVA).