The relations in the workflow template are defined as
follows: Sequence, Parallel, If branch and Handel/Situation
[3].
Sequence: define the sequential relations;
Parallel: define the parallel relations;
If: define the if relations;
Handle/Situation: define the jump relations, since the loop
can be simulated by the if and Handle/Situation, so, there is
no separate definition of the loop relations;
The Task contains two types: task element defines the
manual executed task and agent element defines the entire
automatic executed task. In addition, the agent element
could be used to expand all types of individual requirements
[4]. For example, some of the most commonly used
functions could be introduced into the workflow systems by
defining the different agent elements: operate external data,
send/receive emails, SMS notification, files operation and so
on.
There are the following advantages and disadvantages: