Nowadays, advances in wireless sensing and actuation technology allow for reasonable amounts of application logic to be embedded inside wireless sensor networks. Such applications are more autonomous, but also significantly more complex to program and manage. First, in-network adaptations need to be supported due to the long-lived nature of the network. Second, the intrinsic dynamism of the network challenges how applications interact with each other. Third, as applications become more complex, coordinating their interactions becomes more difficult. This paper explores how the integration of an event-based component middleware, a policy-based management system, and a domain-specific coordination language gives rise to comprehensive support for developing and managing this new breed of applications.

Advances in wireless sensing and actuation technology allow embedding significant amounts of application logic inside wireless sensor networks. Such active WSN applications are more autonomous, but are significantly more complex to implement. Event-based middleware lends itself to implementing these applications. It offers developers fine-grained control over how an individual node interacts with the other nodes of the network. However, this control comes at the cost of event handlers which lack composability and violate software engineering principles such as separation of concerns. In this paper, we present CrimeSPOT as a domain-specific language for programing WSN applications on top of event-driven middleware. Its node-centric features enable programming a node's interactions through declarative rules rather than event handlers. Its network-centric features support reusing code within and among WSN applications. Unique to CrimeSPOT is its support for associating application-specific semantics with events that carry sensor readings. These preclude transposing existing approaches that address the shortcomings of event-based middleware to the domain of wireless sensor networks. We provide a comprehensive overview of the language and the implementation of its accompanying runtime. The latter comprises several extensions to the Rete forward chaining algorithm. We evaluate the expressiveness of the language and the overhead of its runtime using small, but representative active WSN applications.