Information Technology Reference
In-Depth Information
Service
registry
Register
Lookup
Service
provider
Bind and invoke
Service client
Figure 1.1
The Web service triangle.
1.1.2 Workflow Technology
As defined by Workflow Management Coalition (WfMC), a forerunner
in standardizing the workflow technology, workflow is the computer-
ized facilitation or automation of a business process, in whole or part.
This topic focuses on the automation aspect of a business process and
thus will not distinguish between a workflow and a business process
unless otherwise mentioned.
The Workflow Reference Model [6] published by WfMC in 1995
has laid the foundation in defining a vocabulary and architecture of a
workflow system. Despite the drastic technology evolution over the
years, this reference model is still applicable to most workflow systems
in use today. Here, we use this vocabulary to go over the key concepts
in a workflow system and introduce the reference architecture in
Section 1.2.2. The reference model defines a common glossary to
describe business processes (also known as, workflows) and various
artifacts associated with them. It divides the function of a workflow
management system into two aspects, that is, build time and run time.
At build time, a process definition or workflow definition is designed,
usually with the help of a modeling tool, as the representation of a
business process to be automated. Aworkflow definition usually contains
asetofactivities and the sequence among them. An activity can be either
a manual activity that needs human intervention or an automated
