Although coordination of multiple activities is a fundamental goal of object-oriented concurrent programming languages, there is only limited support for its specification and abstraction at the language level. This leads to a mismatch between conceptional designs, using high-level abstractions, and the implementation, using the low-level coordination constructs. Often coordination is hard-wired into the components they coordinate, which leads to evolution, maintenance and composibility problems. We propose a model called FLO/C that relies on the notion of connectors. A connector is an entity that enforces the coordination of the entities it coordinates. This model supports a clear separation between the coordinated active objects and their coordination. An active object only defines specific domain information and a connector only defines coordination between a group of active objects (its participants). The coordination is abstractly defined refering to components in terms of the ob...

Although coordination of multiple activities is a fundamental goal of object-oriented concurrent programming languages, there is only limited support for their specification and abstraction at the language level. This leads to a mismatch between conceptional designs, using high-level abstractions, and the implementation, using the low-level coordination constructs. Often coordination is hard-wired into the components they coordinate, which leads to evolution, maintenance and composibility problems.