Concrete programming with reactive objects

Reactive systems are characterized by an event driven collection of communicating components which respond to internal and external stimuli. We present an approach for enabling the visual development of reactive systems by combining object-orientation and message-passing. Taking the point of view that message-passing is a more natural model for reactive systems than call-based semantics we present the reactive object, a language independent extension to object-oriented programming that adds facilities for inter-object asynchronous communication. The use of concrete visual representations of entities in the domains of message-passing and object-oriented programming we show that reactive objects have the potential to simplify the development of reactive systems.