Information Technology Reference
In-Depth Information
Process
definition
Interface 1
Workflow API and
interchange
Interface 4
Other workflow
enactment services
Interface 5
Admin. and
monitoring
tools
Workflow
engine (s)
Workflow
engine (s)
Interface 3
Interface 2
Workflow
client
application
Invoked
applications
Figure 1.9
The WfMC Workflow Reference Model. Source: Reproduced from
Reference [6].
Aworkflow enactment service interacts with other five components via
five interfaces as illustrated in Figure 1.9.
Interface 1: Process Definition
Interface 1 defines the interchange format for a process definition, and
the API to get it. It is the logic separation between workflow build-time
and run-time. Users may use any tool to build a process definition that
can be fetched by an enactment service via Interface 1 by means of file
transfer or API. To facilitate the exchange of process definitions, in
Interface 1, WfMC also defines a meta-model and process definition
specification, that is, XML Process Definition Language (XPDL) [38].
XPDL is similar to BPEL and BPMN in various aspects but has its own
features. Its meta-model for a process includes the following elements:
Activity, its start and end events, and participants and applica-
tions to perform it.
Gateways, such as AND/OR split or join structures.
