A generalised event handling framework

In earlier work we have developed three domain specific visual approaches for event-based system specification. The first, ViTABaL-WS, uses the Tool Abstraction (TA) metaphor to support specification of web services composition via higher level data and control flows and generation of BPEL4WS code. The second, Kaitiaki, uses an Event-Query-Filter-Action (EQFA) metaphor to allow visual primitives composition and java code generation for diagramming tool event handlers. The third, MaramaTatau, uses a spreadsheet-like metaphor to construct meta-model formulae visually to specify structural dependencies and constraints to be realised at runtime. We propose an integrated visual approach that is generalised from these three explored exemplar approaches to specify event handling behaviours. We derive a canonical event handling model which enables interoperability between these exemplar event models, with also the support for synthesised runtime visualisation. This paper discusses the requirements and design of the resulting general purpose event handling framework, its evaluation and some key future directions.