Introducing Activiti: A Glimpse and [Hopefully] a Hook

Introducing
Rafael Cordones, [email protected], @rafacm
DevFest 2012, November 10th, 2012, Vienna
A Glimpse and [Hopefully] a Hook*
* “A Glimpse and a Hook“: http://www.randsinrepose.com/archives/2007/02/25/a_glimpse_and_a_hook.html

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DevFest 2012 – November 10th 2012 | Vienna
plexiti · pragmatic software productions
Agenda
n Introduction
n How did we all get here?
n Software Development,
Business Processes and
the Business Process Modeling Notation (BPMN 2.0)
n Meet Activiti… and friends!
n Conclusion and discussion
2

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How did I get here?
n Some background information about myself:
n Barcelonian by birth, European by choice. Currently living in
Vienna.
n Experience working for small companies developing web-based
software products for business customers
n Inoculated against the Not Invented Here syndrome and instead
prefer to embrace a Proudly Found Elsewhere attitude!
n Java (ecosystem) developer.
n Disclosure: I’m a partner at plexiti which is itself a partner
with camunda and signavio, companies that develop
products I mention in this presentation.
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How did you get here?
n How many of you have experience with Java development?
n How many of you are familiar with integration projects (B2B)?
n How many of you are familiar with Activiti, jBPM or other business
process engines?
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How did we get here?
n What is a “computer”?
5
Source: “An Illustrated History of Computers”: http://www.computersciencelab.com/ComputerHistory/History.htm

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n The ﬁrst (never built) general-purpose device that could be programmed.
Charles Babbage's blueprint for the Analytical Engine from the 1830s:
6
Seems it will be built after all!
http://plan28.org/
Source:
http://gregoryreher.com/2010/11/building-charles-babbages-analytical-engine/

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n The ﬁrst electronic general-purpose digital computer: the ENIAC (1946)
7
Text
Source: http://en.wikipedia.org/wiki/ENIAC

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n The ﬁrst electronic general-purpose digital computer: the ENIAC (1946)
7
Text
Source: http://en.wikipedia.org/wiki/ENIAC
Flexible plug-in architectures are
not that new after all!

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n “Hello World” in Assembly language for the x86 and Java:
8
section .data
str: db 'Hello world!', 0Ah
str_len: equ $ - str
section .text
global _start
_start:
mov eax, 4
mov ebx, 1
mov ecx, str
mov edx, str_len
int 80h
mov eax, 1
mov ebx, 0
int 80h
class HelloWorldApp {
public static void main(String[] args) {
String msg = "Hello World!";
System.out.println(msg);
}
}
Question: Is this all about lines of code?
Answer: No. It’s about the level of abstraction
at which a language (or technology) allows
you to express and evaluate concepts.
Sources:
http://en.wikipedia.org/wiki/X86_assembly_language#.22Hello_world.
21.22_program_for_Linux_in_NASM_style_assembly
http://en.wikipedia.org/wiki/Java_(programming_language)#Hello_world

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Source: http://en.wikipedia.org/wiki/Thomas_J._Watson
"I think there is a world market for
maybe ﬁve computers"
Mis-attributed to Thomas J. Watson
(Chairman of the Board of IBM, 1943)

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9
Apple
Open Shift
Amazon
Facebook
?
Google

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9
Apple
Open Shift
Amazon
Facebook
?
Google
He seems to have been almost right!

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Would you like to know more?
10
Get the whole tour about the history of computers at:
http://topdocumentaryﬁlms.com/the-machine-that-
changed-the-world/
or even better, read the book
“The Dream Machine: Exploring the Computer Age”!

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Software Development
n Q: Is software development an
individual activity?
A: It depends.
Q: On what?
A: On the context.
11
Source: http://en.wikipedia.org/wiki/
On_the_Internet,_nobody_knows_you're_a_dog
“On the Internet, nobody knows you’re a dog.”
“Any fool can write code that a computer
can understand.
Good programmers write code that
humans can understand”.
-- Martin Fowler

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Software Development
n Q: Is software development an
individual activity?
A: It depends.
Q: On what?
A: On the context.
11
Source: http://en.wikipedia.org/wiki/
On_the_Internet,_nobody_knows_you're_a_dog
“On the Internet, nobody knows you’re a dog.”
“Any fool can write code that a computer
can understand.
Good programmers write code that
humans can understand”.
-- Martin Fowler
Which code?!
To do what exactly?

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Enterprise Software Development
12
Source: http://www.projectcartoon.com

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Large Scale
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“The Tower of Babel” by Pieter Bruegel the Elder (1563). Kunsthistorisches Museum, Vienna.

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n Question: why?
One answer: every participant speaks a diﬀerent language:
n customer’s language, i.e. the business you are in (insurance, trading, …)
n business analyst language
n programming language (Java, .NET, Ruby, Python, … idioms)
n national language and culture (Deutsch, English, …)
14
From “Understanding Comics: The Invisible Art”. Scott McCloud. 1993. Pages 194-195.
Large Scale

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Diﬀerent People, Diﬀerent Languages
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Customers
Software developers
Business
analysts
System
administrators
Product
owners
Sales
Support

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What is a business process?
n Deﬁnition: “a sequence of related, structured activities or tasks that produce a
speciﬁc service or product (serve a particular goal) for a particular customer or
customers.”
16
Source: http://en.wikipedia.org/wiki/Business_process

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When do I need a business process?
n Business process modeling acid test*:
1. Long-running: hours, days, weeks, months, years, …
2. Bursty, sleeps most of the time:
when awake, a flurry of activities and then finished or to sleep again!
3. Persisted state: what happens between different steps or
when the application server goes down?
4. Orchestration of system or human communications:
who has to do what until when? what happens afterwards?
n What about communication? Common shared understanding?
n What about organizational learning?
n How long does it takes us to do X?
n Who did what when?
17
* “Essential Business Process Modeling”, Michael Havey, O’Reilly Press
http://shop.oreilly.com/product/9780596008437.do via http://stackoverflow.com/questions/4869734/how-do-you-know-when-you-need-a-bpm-solution

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Business Process Modeling Notation 2.0
n Example: announcing a job position
18
Source: “Praxishandbuch BPMN 2.0” http://www.bpm-guide.de/2012/02/16/praxishandbuch-bpmn-2-0-in-der-3-auﬂage/

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n Example: announcing a job position explained… ﬁrst tasting:
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Start event
Sequence ﬂow
User (human) task
Pool (participant)
Lane
Gateway (exclusive)
Call activity
(sub-process)
Service
task
End
event
Activities

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n Great! I just need to learn some new symbols and then …
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n Great! I just need to learn some new symbols and then …
20
From the movie: “The Matrix” by Larry and Andy Wachowski. 1999.
WOAH!
I know BPMN 2.0!

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21
In your dreams!
Mister Anderson

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21
In your dreams!
Mister Anderson
“It is diﬃcult, if not impossible, for anyone to learn a subject purely by reading about it, without
applying the information to speciﬁc problems and thereby forcing himself to think about what has
been read. Furthermore, we all learn best the things we have discovered ourselves.”
-- Donald Knuth, “The Art of Computer Programming”*
* Via Alexander Daniel: http://lachdrache.wordpress.com/2012/03/11/reading-•-applying-•-thinking/

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Activities Conversations
Events
Gateways
Conversation Diagram
None: Untyped events,
indicate start point, state
changes or final states.
Message: Receiving and
sending messages.
Timer: Cyclic timer events,
points in time, time spans or
timeouts.
Error: Catching or throwing
named errors.
Cancel: Reacting to cancelled
transactions or triggering
cancellation.
Compensation: Handling or
triggering compensation.
Conditional: Reacting to
changed business conditions
or integrating business rules.
Signal: Signalling across differ-
ent processes. A signal thrown
can be caught multiple times.
Multiple: Catching one out of
a set of events. Throwing all
events defined
Link: Off-page connectors.
Two corresponding link events
equal a sequence flow.
Terminate: Triggering the
immediate termination of a
process.
Escalation: Escalating to
an higher level of
responsibility.
Parallel Multiple: Catching
all out of a set of parallel
events.
Start End
Intermediate
Catching
Throwing
Event Sub-Process
Interrupting
Top-Level
Event Sub-Process
Non-Interrupting
Boundary
Interrupting
Boundary Non-
Interrupting
Sequence Flow
defines the execution
order of activities.
Conditional Flow
has a condition
assigned that defines
whether or not the
flow is used.
Default Flow
is the default branch
to be chosen if all
other conditions
evaluate to false.
Task
A Task is a unit of work, the job to be
performed. When marked with a symbol
it indicates a Sub-Process, an activity that can
be refined.
Transaction
A Transaction is a set of activities that logically
belong together; it might follow a specified
transaction protocol.
Event
Sub-Process
An Event Sub-Process is placed into a Process or
Sub-Process. It is activated when its start event
gets triggered and can interrupt the higher level
process context or run in parallel (non-
interrupting) depending on the start event.
Call Activity
A Call Activity is a wrapper for a globally defined
Sub-Process or Task that is reused in the current
process.
Task Types
Types specify the nature of
the action to be performed:
Send Task
Receive Task
User Task
Manual Task
Business Rule Task
Service Task
Script Task
Markers indicate execution
behavior of activities:
Activity Markers
Sub-Process Marker
Loop Marker
Parallel MI Marker
Sequential MI Marker
~ Ad Hoc Marker
Compensation Marker
A Communication defines a set of
logically related message exchanges.
When marked with a symbol it
indicates a Sub-Conversation, a
compound conversation element.
A Forked Conversation Link connects
Communications and multiple
Participants.
A Conversation Link connects
Communications and Participants.
Inclusive Gateway
When splitting, one or more
branches are activated. All
active incoming branches must
complete before merging.
Complex Gateway
Complex merging and
branching behavior that is not
captured by other gateways.
Exclusive Event-based Gateway
(instantiate)
Each occurrence of a subsequent
event starts a new process
instance.
Parallel Event-based Gateway
(instantiate)
The occurrence of all subsequent
events starts a new process
instance.
Pool
(collapsed)
Multi Instance Pool
(collapsed)
Communication
Sub-Conversation
Pool
(collapsed)
Participant B
The order of message
exchanges can be
specified by combining
message flow and
sequence flow.
Pool Pool
Pools (Participants) and Lanes
represent responsibilities for
activities in a process. A pool
or a lane can be an
organization, a role, or a
system. Lanes subdivide pools
or other lanes hierarchically.
Lane
Task
Lane
Task
Pool
Message Flow
symbolizes information
flow across organizational
boundaries. Message flow
can be attached to pools,
activities, or message
events.
Data
Task
Input Out-
put
Data Store
A Data Object represents information flowing
through the process, such as business
documents, e-mails, or letters.
A Data Store is a place where the process can
read or write data, e.g., a database or a filing
cabinet. It persists beyond the lifetime of the
process instance.
A Data Input is an external input for the
entire process. It can be read by an activity.
A Data Output is a variable available as result
of the entire process.
A Message is used to depict the contents of a
communication between two Participants.
A Collection Data Object represents a
collection of information, e.g., a list of order
items.
Pool (Collapsed)
Collaboration Diagram
Pool (Expanded)
Lane
Lane
Choreographies
Choreography Diagram
A Choreography Task
represents an Interaction
(Message Exchange)
between two Participants.
Choreography
Task
Participant A
Participant B
A Choreography Sub-
Process contains a refined
choreography with several
Interactions.
Multiple Participants Marker
denotes a set of
Participants of the
same kind.
Swimlanes
BPMN 2.0 - Business Process Model and Notation
Collection
Ad-hoc Sub-Process
Task
Task
~
Message
Start Event
Message Flow
Data Object
Collapsed
Sub-Process
Event-based
Gateway
Escalation
End Event
Timer
Intermediate
Event
Receive Task
Attached
Intermediate
Timer Event
Link
Intermediate
Event
Manual Task
End
Event
Data
Store
Link
Intermediate
Event
Parallel
Multiple
Intermediate
Event
Text Annotation
Group
Multi Instance
Task (Parallel)
Message
End Event
Send Task
Parallel
Gateway
Exclusive
Gateway
Attached
Intermediate
Error Event
Signal
End
Event
Call Activity
Sub-Process
Event Sub-Process
Conditional
Start Event
Error End
Event
Start
Event
End
Event
Looped
Sub-Process
condition
http://bpmb.de/poster
Participant A
Participant C
Participant B
Choreography
Task
Participant A
Participant B
Choreography
Task
Participant A
Participant C
Initiating
Message
Response
Message
Choreography
Task
Participant B
Participant A
When splitting, it routes the sequence flow to exactly
one of the outgoing branches. When merging, it awaits
one incoming branch to complete before triggering the
outgoing flow.
Exclusive Gateway
Is always followed by catching events or receive tasks.
Sequence flow is routed to the subsequent event/task
which happens first.
Event-based Gateway
When used to split the sequence flow, all outgoing
branches are activated simultaneously. When merging
parallel branches it waits for all incoming branches to
complete before triggering the outgoing flow.
Parallel Gateway
Choreography
Sub-Process
Participant A
Participant C
Participant B
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And THE poster!
PDF: http://www.bpmb.de/images/BPMN2_0_Poster_EN.pdf
Printed: http://www.signavio.com/joomla/de/bpmn-poster.html
Get THE book!
German: http://www.bpm-guide.de/2012/02/16/
praxishandbuch-bpmn-2-0-in-der-3-auﬂage/
English: http://www.bpm-guide.de/2012/10/30/real-life-
bpmn-2-0-book-now-available-in-english/
Get the BPMN 2.0 Examples at: http://www.omg.org/cgi-bin/doc?dtc/10-06-02

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n Question: Is this a business process?
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n Answer: No. It’s a model of a business process!
24
Picture sources: http://en.wikipedia.org

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n Answer: No. It’s a model of a business process!
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All models are incomplete!
But they serve very well their role as a common shared understanding.
Picture sources: http://en.wikipedia.org

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n The point is not to have a great model, the point is to ship software!
n In every moderate to complex software project:
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n The point is not to have a great model, the point is to ship software!
n In every moderate to complex software project:
25
[T]here are known knowns; there are things we know that we know.
There are known unknowns; that is to say there are things that, we now know we don't know.
But there are also unknown unknowns – there are things we do not know we don't know.
--- United States Secretary of Defense, Donald Rumsfeld

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Meet Activiti
n Light-weight workﬂow and Business Process Management (BPM) platform
n Able to execute BPMN 2.0 business processes
n For business analysts, developers and system admins
n Open-source and distributed under the Apache License 2.0
n Activiti runs in any Java application or web application server
n Integrates with Spring
n Has a REST API
26
http://activiti.org

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Meet Activiti
n An engine or a platform? Both!
27
Source: http://activiti.org/components.html

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Diﬀerent People, Diﬀerent Needs
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Customer
Software developers Business analysts
System administrators
Activiti Designer
Activiti Engine
Activiti Probe
Activiti Modeler
Activiti Explorer

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Meet Activiti (demo)
n Installing and starting the Activiti demo project
n Exploring the packaged examples
n Developing process applications:
n What about testing?! --> unit testing your processes
n Connecting the process to your business logic (services, …)
n Deploying the process and related resources
n “Using” the process
n Monitoring the process
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Hi!
I’m Kermit!

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Hi!
I’m Kermit!
I’m Gonzo!

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Hi!
I’m Kermit!
I’m Gonzo!
And
I’m Fozzie!

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… and friends: camunda fox
n Commercially supported version of Activiti
n Focus on the Java EE / CDI environment
n JBoss, Glassﬁsh, WAS, … application servers
n Improved tooling: designer, cockpit, cycle, …
n Full featured comparison here:
http://www.camunda.com/fox/product/features/
n Development and production support
n camunda employs a good portion of the
Activiti core developers
n Open Source Community Edition also available!
http://www.camunda.com/fox/
n camunda fox open source strategy:
http://www.bpm-guide.de/2012/02/17/camunda-fox-open-source-strategy/
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The Job Announcement Showcase
n A kick-start application for your
business process-centric project!
n Java EE 6 technology stack
n camunda fox BPM Platform
n Try online at:
http://the-job-announcement.com/
n Fork, clone, modify, … at
https://github.com/plexiti/the-job-
announcement-fox
n Feedback highly appreciated!
n More to come: http://plexiti.com/blog
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The Job Announcement Showcase
n Demo
32

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Conclusions
n BPMN 2.0 process diagrams as
n means of communication and sharing knowledge between project participants
n executable in an open-source business process engine like Activiti
n Question: do we need software developers anymore then?! Answer: Sure!
n Zero-code: business analysts will be able to “draw” the processes themselves.
Snake oil!
n Less-code: software developers can focus on implementing what brings value.
n There’s no silver bullet!
“No Silver Bullet — Essence and Accidents of Software Engineering”
http://www.cs.nott.ac.uk/~cah/G51ISS/Documents/NoSilverBullet.html
“All non-trivial abstractions, to some degree, are leaky”
http://www.joelonsoftware.com/articles/LeakyAbstractions.html
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n For the technical side of process-based application implementation:
n “Wie man Workﬂows mit Activiti als Open Source Process Engine
leichtgewichtig in die Java-Welt bringt”
by Daniel Meyer and Bernd Rücker
http://www.camunda.com/wp-content/uploads/2012/06/JM_6_12_Meyer_R%C3%BCcker_Activiti.pdf
34
“Activiti in Action:
Executable business processes in BPMN 2.0”
by Tijs Rademakers
http://www.bpmnwithactiviti.org/
Discount code available on the Activiti website!
http://activiti.org/

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Discussion
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Answers to Discussion Questions
n Q: “Since you are using EL expressions, are you forced to use JSF?”
A: No! Check out this cool AngularJS-based demo for camunda fox by
Daniel Meyer and Nico Rehwaldt:
Demo: http://showcase-camundafox.rhcloud.com/fruit-shop/app/index.html
Code: https://github.com/meyerdan/order-processing-demo
n Q: I presume Activiti is only for Java-based projects, or?
A: No! Activiti also oﬀers a REST API!
http://activiti.org/userguide/index.html#N12855
n Q: Must all the application data be also stored in the Activiti database tables?
A: Not at all! See here on how to use your JPA-based model entities with Activiti
http://activiti.org/userguide/index.html#N1200A
n Q: Is designing process models only available as Eclipse plug-in?
A: No! See the
Activiti Modeler: http://bpmn20inaction.blogspot.nl/2012/09/activiti-modeler-getting-started-part-1.html
Signavio Process Editor: http://www.signavio.com/products/process-editor/process-modeling/
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Thanks!
Rafael Cordones, [email protected], @rafacm
DevFest 2012, November 10th, 2012, Vienna

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Introducing Activiti: A Glimpse and [Hopefully] a Hook

Introducing Activiti: A Glimpse and [Hopefully] a Hook

Rafael Cordones

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