Page 228 -

Chapter 8
The Design Environment

Stephan Clemens, Marcello La Rosa, and Arthur ter Hofstede

8.1 Introduction

The core modeling component of the YAWL System is the Editor. This tool enables
workflow designers to graphically define complex process models, and to analyze
and export these models to the Engine.
Specifically, the Editor is a rich client application offering visual support for the
definition of the process control logic, the data associated with the process and its
tasks, and the organizational resources participating in the process. An important
aspect of the Editor is the provision of sophisticated logic to verify the produced
models. Through this capability, a designer can pinpoint syntactical and semantic
issues at a mouse click, so as to avoid potentially costly mistakes before deploying
a process to a workflow engine.
The main driver behind the development of a visual editor for YAWL was the
necessity to speed up the creation of process models and to foster the uptake of the
language by nontechnical users. In light of this, the Editor had to fulfill the require-
ments of free availability, portability, ease of use,and interoperability. The tool had
to be freely available; therefore, it was decided to release it under the open source
LGPL license. Portability was guaranteed by developing the Editor in Java TM and
avoiding any code dependency on OS-specific libraries. Ease of use was achieved
by providing the Editor with an intuitive user interface on top of a core graphical
1
component based on extensions to the JGraph libraries. Interoperability was sup-
ported by the definition of a common XML format and a set of API calls for the
exchange of workflow specifications between an editor and the runtime environ-
ment (cf. Chap. 9). The interaction between design and runtime environment in the
YAWL System is depicted in Fig. 8.1.
The decision to minimize the dependencies between the design environment and
the runtime environment via the use of a common interchange format and a set of

1
www.jgraph.com
S. Clemens (B )
Queensland University of Technology, Brisbane, Australia
e-mail: stephan.clemens@qut.edu.au

A.H.M. ter Hofstede et al. (eds.), Modern Business Process Automation, 221
DOI 10.1007/978-3-642-03121-2 8, c Springer-Verlag Berlin Heidelberg 2010