PV207 – Business Process Management
Spring 2021
Jiří Kolář, Lubomír Dočkal, Lubomír Hruban
Process
modeling II
Lecture overview
● From L1 to L2
● L2: timing precision
● BPMN 2.0 Level 2:
○ Subprocess
○ Activity call
○ Events
■ Messages
■ Signals
■ Errors
■ Escalations
○ Gateways
○ BPMN 2.0 summary
BPMN 2.0: from L1 to L2
● Level 1
○ Flowcharting
○ Business experts <=> analysts/developers
○ The goal is to express simple activity sequences
○ Minimum of nesting and interprocess interactions
○ Simple events only
● Level 2
○ Analytical BPMN model
○ Process analysts <=> Process developers
○ Precise activity execution timing
○ Subprocess nesting and interprocess interactions
○ Events and signals, exception handling
Level 2: timing precision
● Each activity has exact start and
completion
● Service task
○ Starts immediately when reached
○ Being performed immediately and completed
● User task
○ Starts immediately when reached
○ Being performed once user open it in a
”worklist” = task “claim”
Level 2: timing precision
example
Subprocess vs Call activity
● Subprocess
○ Expandable
(nested) part of the process
○ Defined inside process
○ Nested for better readability
● Activity call
○ Call of global task or process
○ Defined as a separate process, then imported
○ Reusable in other processes
Event types: Basic types
● Start events
○ Event initiate process/subprocess
○ One (or more in very special cases)
○ Always catching
● Intermediate events
○ Occur during process
○ Can be throwing or catching
● End events
○ Occur at the end of process flow
○ Always throwing
○ End affect only one branch (except Terminate)
Event types - Examples
EventsDownloaded from:
http://frapu.de/blog/index.php?m=07&y=09&d=01&entry=entry090701-211320
Event types:
Catching vs. Throwing
● Throwing
○ Emits the event
○ Flow continues immediately
● Catching
○ Catch the event
○ Flow waits for the event
picture source: http://www.activiti.org/userguide/, http://mainthing.ru/wp-content/uploads/2010/11/message-e.png
Event types:
Interrupting vs non-interrupting
picture source: http://www.processmodeling.info/posts/highlights-from-bpmn-2-0-non-interrupting-events/
● Interrupting
○ Standard process flow is interrupted
○ Flow is directed through the event
● Non-interrupting
○ Standard flow continues normally
○ Parallel flow is directed through the event
Event types:
Interrupting vs non-interrupting
picture source: http://processpedia.com.au/community/wp-content/uploads/Order-Procurement-Process-Map-Example.png
● Message represents a message send by
external entity ~ Pool
○ Messaging is for interprocess communication
○ Inside the process use sequence flow instead
● Message does not have to be JMS, SOAP
etc. but it can be fax, mail, SMS etc.
● A Message can be received and start process
● A message can occur as intermediate event
● A message can be sent at the end of process
Event semantics:
Messages
Event semantics:
Message - examples
Event semantics:
Signals
● Signal is similar to message, except
○ Is not addressed to any particular consumer
○ Entity producing signal does not “care” who is listening
○ Many instances of the same process can consume it
○ Good for loosely coupled communication
○ Signals are used often inside one process, messages not
Event semantics:
Timer
● Cyclic events
● Points in time
● Timeouts
● Handling unusual but expected behaviour
○ Corrective actions (interrupting)
○ Additional steps to be done in parallel (non-interrupting)
Event semantics:
Escalations
picture source: http://processpedia.com.au/community/wp-content/uploads/Order-Procurement-Process-Map-Example.png
Event semantics:
Errors
● Used for serious problem in process
● Throw - catch mechanism
○ Always interrupting
○ Always boundary event
● There should be some error handling actions
picture source: http://www.activiti.org/userguide/, http://mainthing.ru/wp-content/uploads/2010/11/message-e.png
Event-based gateway
● Event-based gateway
○ Branching based on event, only one triggered
○ Different semantics – branched according to
event that is placed after the gateway
Multi-instance and Loop
activity
● Multi-instance
○ Shortcut for a number
(dynamically defined) of the
same activities that run in
parallel or in series.
● Loop
○ Shortcut for a repeating
one activity until a
condition is met.
What is in not covered here
● Transactional events
○ Compensations
○ Cancellations events
○ Rollbacks
● Other diagrams covered in BPMN 2.0 specs
○ Choreography diagrams
○ Conversation diagrams
FIN
Questions?
PV207 – Business Process Management
Spring 2021 Jiří Kolář, Lubomír Dočkal