Composing Collaborations Using Adaptive Behavioral Components

A programming model is presented that goes beyond traditional object-oriented (OO) programming models by providing a construct, called an adaptive behavioral component, for capturing class collaboration. An adaptive behavioral component (ABC) represents a level of abstraction above that of a class. The implementation of a speciic task is traditionally spread out over several methods in diierent classes. ABCs allow the encapsulation of such a slice of collaborative behavior into a single program unit, which can itself be instantiated. Adaptive behavioral components employ a unique composition mechanism in which multiple behavioral objects may exist simultaneously and collaborate with one another to accomplish a task. The concept of ABCs is complementary to the concepts employed in current OO models, and can be used to extend existing OO languages. In addition to supporting behavioral abstraction, ABCs support an adaptive style of software speciication. Thus behavior is implemented in a manner resilient to change in class structure.