About Step Transition Behavior

Process model transitions are executed in the Process Engine. The Process Engine carries out step transitions in a defined order based on the design of the model. Generally:

Step-level exceptions (such as errors, timeouts, and maximum iteration counts) are first. For more information about step exceptions, see About Transition Exceptions.

These are followed by transitions, both with and without conditions.

If the Process Engine does not encounter any of these, it moves on to the process-level timeout.

In the course of executing the steps in a process model, the Process Engine employs a set of guidelines known as Standard Exception Handling. The Process Engine follows the Standard Exception Handling order when it encounters no other specific guidance at the step level. For more information, see About Transitions and Standard Exception Handling.

The Process Engine executes step transitions as follows.

The following table explains what happens before the step is executed:

If	The Process Engine
There is a join expression on a step and that expression is not satisfied at run time.	Takes the Unsatisfied Join transition, if defined. When an Unsatisfied Join transition is not defined, the process executes Standard Exception Handling. See About Transitions and Standard Exception Handling.
The step has exceeded its Step Retry Count.	Takes the Step Iterations Exceeded transition. When a Step Iterations Exceeded transition is not defined, the process Executes Standard Exception Handling. See About Transitions and Standard Exception Handling.

The following table explains what happens while the step is executing:

If	The Process Engine
The step encounters an error.	Executes Standard Exception Handling. See About Transitions and Standard Exception Handling.
The step has an intermediate boundary interrupting timer event, and its Timer Condition is met before the step completes.	Takes the step’s Timer Condition transition. See Configuring a Boundary Intermediate Event.

The following table explains what happens after the step has executed:

If	The Process Engine
There are transitions without conditions.	Takes them.
There are "if" conditions that are satisfied.	Takes them.
There are "if" conditions that are not satisfied and there is an "else" transition defined.	Takes the "else" transition.

The following table explains what happens at any point:

If	The Process Engine
A join has a timeout value specified and one of the required paths never reaches the step.	Takes the first of the following transition types it encounters: 1. Step timeout transition. 2. Process-level timeout. 3. Standard Exception Handling. See About Transitions and Standard Exception Handling.
A process-level timeout is defined and it expires at any point during the process.	Executes the process-level Timeout Handler Step.
No process-level Timeout Handler Step is defined.	Executes the process-level Error Handler Step.
No process-level Error Handler Step is defined.	Sets the process instance to Failed.