Executable HMI Specifications with Flash and Yakindu Statecharts

Human machine interfaces (HMI) are inherently interactive and dynamical. An important goal of HMI engineering is to optimize the interaction between the human being and the machine. The ergonomics and efficiency of an HMI is mainly driven by the quality of its design. This makes the HMI design a central part of HMI specifications. Due to the HMIs dynamical nature the design must cover the interfaces functional behavior as well as its form and appearance. From this point of view executable specifications would be desirable.

Statecharts are an executable formalism that can be used to specify the reactive behavior of HMIs at an adequate level of abstraction. Using statechart the function can be specified very well, but statecharts do not cover the design aspect of form at all. So they can't provide any concrete visual experience. This part could be covered by different approaches. A prominent one is to use Adobe's Flash technology for prototyping visual designs. Flash allows rich visual effects including animations etc. and is very popular in the 'design oriented' disciplines. So putting both together seems to be a promising approach - and that is what we did. We integrated our Yakindu Statechart Tools with Flash applications and set up two showcases. The first shows a electric window lifter and the second an interactive driver information panel.

Check out the the screencast to get an impression how the solution works.

Each showcase consists of a Flash application, a statechart, and a simple textual mapping model that describes how Flash and statechart events and data have to be mapped towards each other.Technically the mapping model is used to generate a flash component that has to be embedded into the  Flash application. This component registers the appropriate event handlers and handles the communication issues with the Yakindu statechart simulator that executes the statechart. When working with the Flash based design active states, transitions, and value changes are also visualized on the model level.

The whole tooling is based on the Eclipse platform. The Adobe Flash Builder is based on Eclipse as well as the Yakindu Statechart Tools and the mapping model including the model parser and the rich editor including content assist for references to Flash components is based on Eclipse Xtext technology.

This approach brings up some interesting questions. First of all - how can the formal statechart model help when it comes to the concrete implementation of the HMI? Can it be used to generate code? What are the preconditions and must the statechart be refined for that purpose? I think i will cover some of these questions in following posts.

Another interesting point is of course that this approach also can be useful for other use cases than HMI specifications. It can be used whenever a visual rich animated frontend will be required in simulation contexts. And of course Flash applications may be integral part of  concrete System implementations...

First Embedded Project at Eclipse Labs

At the weekend i set up the yakindu project at Eclipse Labs. Initially we planned to provide public access to source code, issue tracker, forums, etc. by hosting the project on Sourceforge. That plan changed when the Eclipse Foundation announced on May 13th that they coorperate with Google on the project hosting platform Eclipse Labs. Since that platform is closer to Eclipse and promises a much better visibility of the Yakindu Tools (and even though it has some drawbacks compared to the functionality of the Sourceforge platform) we decided to switch to that hosting platform.

So when i created the project (and still now) the yakindu project is the only project in the category Embedded. The project already provides access to the source code, the public issue tracker, and a user forum (a google group). Since thee is a qouta for the downloads at Eclipse Labs we still have to decide how to handle the downloads of the Yakindu Eclipse Distributions (they are currently still on Sourceforge).  We also will continue to host our continuous build system on the Hudson server at itemis.

I am very curious how Eclipse Labs will develop since it is still in an early phase. Currently there are 318 projects - that means more than 10 projects a day have been registered per day in average. That is promising.

Axel

PS: Some Links...

• http://www.yakindu.com


• http://eclipselabs.org/p/yakindu

Yakindu Statechart Tools 1.1.0

At the beginning of this month we have built the 1.1.0 release of the Yakindu Statechart Tools (SCT). This version is build for Eclipse 3.5 (Galileo). And contains some important improvements like:

• a new simulation engine that applies the java code generator to make sure that simulation and generated java code behave identical


• validation for statechart expressions. The textual elements will be parsed and error markers will be set if an expression is invalid.


• simple editing actions for reordering transition priorities.


• improved Eclipse-UML integration


• a lot of more things.

Some of these features are also contained in the probably last release 1.0.0-M04 for Eclipse 3.4 Ganymede. The new release is available from the Yakindu update site: http://updates.yakindu.com/galileo/release or from the Yakindu download site.