It is increasingly common to use metatools to specify and generate domain specific visual language tools. A common problem for such metatools is specification of model level behaviours, such as constraints and dependencies. These often need to be specified using conventional code in the form of event handlers or the like. We report our experience in integrating a declarative constraint/dependency specification mechanism into a domain specific visual language metatool, focussing on the tradeoffs we have made in the notational design and environmental support used. The expressive power of the mechanism developed is illustrated by a substantial case study where we have redeveloped a complex visual tool for architectural modelling, eliminating conventional event handlers.

We are exploring existing approaches and developing new techniques for visual event-based system integration. We are using domain-specific visual languages with different high-level visual metaphors (including Tool Abstraction, Event-Query-Filter-Action and Spreadsheet) to specify event-handling support and provide backend processing tool support for event integration specification and visualisation of event propagation. We aim to generalise from three exemplar visual event-driven system metaphors and develop a new, generic visual event handling metaphor. From this we will build a visual environment for specifying event-based system integration. The visual metaphor we are developing should adapt the event-based communication model to a wide range of application domains, and also should support complex and intelligent system design and implementation.

Domain-specific visual language editors are useful in many areas of software engineering but developing such editors is challenging and time-consuming. We describe an approach to generating a wide range of these graphical editors for use as plug-ins to the Eclipse environment. Tool specifications from an existing meta-tool, Pounamu, are interpreted to produce dynamic, multi-view, multiuser Eclipse graphical editors. We describe the architecture and implementation of our approach, examples of its use realizing domain-specific modelling tools, and strengths and limitations of the approach

Implementing complex web service-based systems requires tools to effectively describe and co-ordinate the composition of web service components. We have developed a new domain-specific visual language called ViTABaL-WS and built a prototype design tool to support modelling complex interactions between web service components. ViTABaL-WS uses a "Tool Abstraction" metaphor for describing relationships between service definitions, and multiple-views of data-flow, control-flow and event propagation in a modelled process. The tool supports the generation of Business Process Execution Language (BPEL) definitions from a model, directly deploys a generated model to a workflow engine, and supports dynamic visualisation of a running BPEL process.

We describe a new visual language for event handling specification and its incorporation into Pounamu, a meta-tool for building diverse visual design environments. Our visual language provides end users ways to express event handling mechanisms via visual specifications.

We have introduced zoomable user interfaces into Pounamu, a visual language meta-tool, providing enhanced view navigation and management features. The zoomable user interfaces provide the user with support for flexible and dynamic design overviews and view element focus, and help address problems of lack of screen space and display capability in complex views