Composing features and resolving interactions

Abstract

One of the accepted techniques for developing and maintaining feature-rich applications is to treat each feature as a separate concem. However, most features are not separate concerns because they override and extend the same basic service. That is, "independent" features are coupled to one another through the system's basic service. As a result, seemingly unrelated features subtly interfere with each other when trying to override the system behaviour in different directions. The problem is how to coordinate features' access to the serviee's shared variables.This paper proposes coordinating features via feature composition. We model each feature as a separate labelled-transition system and define a conflict-free (CF) composition operator that prevents enabled transitions from synchronizing if they interact: if several features' transitions are simultaneously enabled but have conflicting actions, a non-conflicting subset of the enabled transitions are synchronized in the composition. We also define a conflictand violation-free ( CVF) composition operator that prevents enabled transitions from executing if they violate features' invariants. Both composition operators use priorities among features to decide whether to synchronize transitions.

Architecture Challenges for Intelligent Autonomous Machines

“…From an architectural perspective, it can be addressed by two complementary approaches [18]. The rst approach is 'correctness by construction' which refers to the principles and mechanisms of composing systems out of subsystems in a way that there are no unexpected side e ects or emergent behavior.…”

Correct-by-Construction Web Service Architecture

“…In light of the latest developments regarding the proof of several attractive properties of BIP (expressiveness, incrementality, scalable analyses and correct-by-construction model transformations), we expect important new results on long-standing research problems related to our work. One such problem is the problem of feature interaction, as it is known in the area of telecommunication systems and services [27]. In the context of our work, this problem appears when a formal Web Service architecture for a SOAP-based or RESTful application is to be composed with another architecture, in order to provide various service qualities such as fault tolerance, atomicity etc.…”

A relationship-based approach to model integration

“…While the term "composition" is overloaded, in this article we use it to represent integration of models which are treated as black-box artifacts, so the model relationships are established between the interfaces that the models expose to the outside world. The composition is typically sequential or parallel (e.g., [5,13,17,25]), and we focus on the latter [5], describing how it can be applied to components represented by state machines.…”

“…Despite the lack of a well-defined terminology, the literature broadly distinguishes three core types of model integration activities, called merge [35,28,43,41,8,3,7], composition [5,13,17,25] and weaving [26,40,12,11]. Given a particular integration context, which of the activities is appropriate?…”