The States of Activity
Defined workflow use process method to describe the
activity relationship, activity's properties, initial conditions
and the status of each stage. The activity of the workflow can
be abstracted as a set of six elements:
Workflow=. "O" is origin state, "R" is ready state, "P" is
perform state, "S" is suspend state, "E" is end state, "F" is
finish state. The state transition among these activities is
shown as figure 2.