Object-Oriented Model for Extensible Concurrent Systems: The Composition-FiltersApproach

摘要

Applying the object-oriented paradigm for the development of large and complexsoftware systems offers several advantages, of which increased extensibility and reusability are the most prominent ones. The object-oriented model is also quite suitable for modeling concurrent systems. However, it appears that extensibility and reusability of concurrent applications is far from trivial. The problems that arise, the so-called inheritance anomalies are analyzed and presented in the paper. A set of requirements for extensible concurrent languages is formulated. As a solution to the identified problems, an extension to the object-oriented model is presented; composition filters. Composition filters capture messages and can express certain constraints and operations on these messages, for example buffering. The paper explains the composition filters approach, demonstrates its expressive power through a number of examples and shows that composition filters do not suffer from the inheritance anomalies and fulfill the requirements that were established.