Using role-based coordination to achieve software adaptability

Abstract

Software systems are becoming more open, distributed, pervasive, and connected. In such systems, the relationships between loosely-coupled application elements become non-deterministic. Coordination can be viewed as a way of making such loosely coupled systems more adaptable. In this paper we show how coordination-systems, which are analogous to nervous systems, can be defined independently from the functional systems they regulate. Such coordination-systems are a network of organisers and contracts. We elaborate how contracts can be used to monitor, regulate and configure the interactions between clusters of software entities called roles. Abstract management contracts regulate the flow of control through the roles and provide monitoring interception points. Concrete contracts are domain specific and allow the specification of performance conditions. These contracts bind clusters of roles into self-managed composites -each composite with its own organiser role. The organiser roles can control, create, abrogate and reassign contracts. Adaptive systems are built from a recursive structure of such self-managed composites. A prototype framework has been built from which adaptive applications can be derived. This framework uses association-aspects as a mechanism to implement contracts.

Towards Knowledge-intensive Software Engineering Framework for Self-Adaptive Software

“…A contract is the specification of the interaction between roles [21]. A contract includes the process and the measurement.…”

Dynamic Protocol Aggregation and Adaptation for Service-Oriented Computing

“…Our approach is to use the ROAD (Role-Oriented Adaptive Design) framework [6,7] to model the service composition as a role-based structure. In the above scenario, there are three roles: Buyer, Broker and Vendor.…”

“…In this way contracts perform a similar function to interceptors in conventional middleware. As specified in our previous work [6,7], ROAD contracts have the functions of Interaction Monitor (monitoring the messages sent and received between roles) and Request-Response Transaction Monitor (monitoring and associating between request and response messages). In this paper, we extend its function to include the Protocol Monitor which maintains the state of the conversations (sequences of transactions) between the roles involved in the contract and checks if they follow the predefined protocols.…”

“…The approach taken in this paper is to maintain a run-time organisational representation of the service composition using the ROAD (Role Oriented Adaptive Design) framework [6,7]. This representation is internal to the compositional infrastructure, which includes entities that represent abstract service definitions (roles) and contracts between those roles.…”

The Four Major Challenges of Engineering Adaptive Software Architectures

“…Our approach to the management indirection using organisational structures is called ROAD (RoleOriented Adaptive Design) [6,7]. ROAD is based on a few fundamental concepts: roles, contracts and selfmanaged composites that have internal organisers.…”