States of Transition Instances

A transition transfers data between nodes.

During runtime, the colors of the transition arrows in the Workflow Creation Tool correspond to the colors of the node states:

Complete state

Normally a transition fires and provides data (it is going to provide) to the input of the target node which can then become active, when the activity contained in the source node completes.

Generally, we say that a transition has fired when no more events can affect whether or not it provides data. There are no (more) outstanding prerequisites or unknowns which might affect whether the transition will provide data.

Incomplete state

• It may happen, that a transition has not provided data but has fired.

  For example, in the case of two transitions coming from a condition node. The condition node provides two output arguments Yes and No. If the node reaches the state DONE, both transitions will fire but only one (depending on the result of the condition) will provide a value and will thus pass the flow to the appropriate branch of the workflow. In this case, there are no outstanding unknowns – the other transition will not provide data for this instance of the workflow.

• There is a special case where a transition has provided data (which can not be used by the target node which will not become active) but must wait before it can fire.

  If the source node belongs to a group of nodes which are a part of the same transaction (i.e. the Keep current transaction flag on the connecting  transitions is set to TRUE), then it can happen that the transition has provided a value, but has not fired yet. The transition can fire and provide data to the target node, only when the whole transaction is committed.