Each workflow definition describes one process. A process can take several states as shown in Figure 4.3, “State diagram of a process”.
There are five operations which can be applied to a process, depending on its state:
create a process
If a process is created, the variables of the process are initialized. The Site Manager opens a form for this, where the user can enter the values of the workflow variables depending on the tasks client view. The workflow is in the state not_started, so no task is activated yet.
start a process
If a process is started, it switches to the state running and starts executing with its start task.
suspend a process
A running process may be suspended by an authorized user. The further execution of all tasks is paused until the process is resumed again. Thus, tasks can neither be accepted nor delegated or completed if a process is in state suspended.
resume a process
If a process was suspended it may be resumed by an authorized user and continues where it had paused before.
abort a process
A process may be aborted by an authorized user in any substate of the state open. Aborting a process means deleting it. The actions which took place as part of the workflow so far are not rolled back, so, for example, approved resources remain approved.
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