2. About me: Tammo van Lessen
 SOA/BPM Consultant
 Working on Intalio|BPMS Server
 Member of the BPMN 2.0 FTF
 Apache Software Foundation
 Member
 Apache ODE: PMC Chair, Committer
 Book author
 German book about BPEL
 Researcher @ IAAS, University of Stuttgart
© Tammo van Lessen 3

3. The Talk Today
 Motivation for BPM
 BPM & IT
 Business Process Lifecycle
 Programming in the Small vs. Programming in the Large
 Workflow Languages / Standards / Status Quo
 WS-BPEL concepts
 Summary
© Tammo van Lessen 4

4. Business Processes: A Definition
 Hammer & Champy [1993]
 “a collection of activities that takes one or more kinds of input
and creates an output that is of value to the customer.”
 Davenport [1992]
 “a structured, measured set of activities designed to produce a
specific output for a particular customer or market. It implies a
strong emphasis on how work is done within an organization,
in contrast to a product focus’s emphasis on what. A process is
thus a specific ordering of work activities across time and
space, with a beginning and an end, and clearly defined inputs
and outputs: a structure for action. ... Taking a process
approach implies adopting the customer’s point of view.
Processes are the structure by which an organization does what
is necessary to produce value for its customers.”
© Tammo van Lessen 5

5. Motivation
 Modeling Business Processes
 You understand what is happening in your organization.
 You understand who is responsible for certain tasks.
 You understand which resources are involved.
 Simulating Business Processes
 You understand how your processes could be optimized.
 You can identify bottlenecks, dead locks, waste of time and
resources.
 Executing Business Processes
 You can automate parts of your business processes.
 You can implement changes to your processes as you go.
 Monitor Business Processes
 You can get a health status of your organization in real time.
 Optimize Business Processes
 You can continuously improve your organization’s processes.
© Tammo van Lessen 6

6. Business Process Lifecycle
Model
Optimize Implement
Monitor/
Execute
Analyse
© Tammo van Lessen 7

7. Process == Product
 Best practice:
 Take the customer’s point of view
 Your process is your product and vice versa (on certain
levels)
 Products can be composed of other products (recursion)
 Process Model:
 Abstract view on how a product is
build/composed/manufactured
 Process Instance
 Abstract view on a concrete product
© Tammo van Lessen 8

8. Business Process Modelling Notation (BPMN 1.x)
 Notation for business experts to analyse, document
and discuss business processes.
 Activities, Gateways, Events
 Control & Data flow (Sequence Flow, Data Objects)
 Organisational modelling (Pools, Lanes)
 No defined execution semantics!
 Calls for a technical language for business process
automation
© Tammo van Lessen 9

9. Business Process Execution Language (BPEL)
 Standardized XML-based language for executable,
technical business processes
 Hybrid language: block-structured & graph-based
 Well-defined execution language
 No dead-locks, no lack-of-synchronization
 Graphs must be acyclic
 Tied to concepts of SOA/Web Services
 No support for human activities
 No notation!
© Tammo van Lessen 10

10. BPMN + BPEL
 Established Approach
 Business experts create BPMN models
 IT experts translate them to BPEL in order to make them
executable
 Problem
 Mapping BPMN to BPEL is not straight forward
 Lax vs. strict semantics
 Loops / Blocks
 Lack of technical details in BPMN models
 Roundtripping is difficult
© Tammo van Lessen 11

11. Business Process Model and Notation (BPMN 2.0)
 Best of both worlds
 A notation (subset) for BPEL
 A meta model and execution semantics for BPMN
 Notational support for Choreographies
 BPMN 2.0 models
 are now interchangeable
 can be executed
 can carry technical details
© Tammo van Lessen 12

12. Mind the Gap
 BPMN 2.0 does not
automatically bridge
the Business/IT gap
 Don‘t entirely trust
the business model
 Business model and
technical model
may diverge
 Be careful with
blocking/non-
blocking tasks
© Tammo van Lessen 13

13. How Much BPMN do you Need?
 BPMN is very complex
 Try to agree on subsets
 Discuss your models
zur Muehlen, M.; Recker, J.: How much BPMN do you need?
http://www.bpm-research.com/2008/03/03/how-much-bpmn-do-you-need/
© Tammo van Lessen 14

14. Business Process
Execution
© Tammo van Lessen 15

15. Different Kinds of BPMS (1)
 The “commercial” model
 Standards-based
 Proprietary extension
 Closed-source
 Typically well tested & supported
 Often combined with consulting & support offerings
 The “open source” model
 Standards-based and/or proprietary
 Source code is available for free
 Tech experts needed to get started
 The “commercial open source” model
 Based on open source
 Sell technical experience, glue code, consulting & support
 E.g. Intalio, WSO2, Redhat,…
© Tammo van Lessen 16

16. Different Kinds of BPMS (2)
 The “embedded” approach
 Light-weight process engine
 Can be easily integrated into your application
 Java-centric
 E.g. jBPM, Drools Flow, Activiti
 The “SOA” approach
 Architecture typically more heavy-weight
 Orchestrates services to achieve a higher business goal
 Service implementation is hidden by an interface and is
exchangeable (mostly Web Services).
 E.g. Apache ODE, IBM, Oracle, SAP,…
© Tammo van Lessen 17

17. The Basis: Service Platform
Orchestration Protocols State
Components
Discovery, Negotiation, Agreement
Composite Atomic
Reliable Quality
Security Transactions
Messaging of Service
Interface + Bindings Policy Description
XML Non-XML Messaging
Transports Transport
© Tammo van Lessen , Frank Leymann

18. The Basis: Web Service Platform
WS-C, WS-CDL,
BPEL WSRF
BPEL4Chor Components
Composite Atomic
UDDI, WS-A, WS-MEX, WSIL
Quality
WSRM WS-Security* WS-AT, WS-BA,…
of Service
WSDL WS-Policy* Description
SOAP, WS-A JMS, RMI/IIOP Messaging
HTTP, SMTP, XMPP, TCP/IP, FTP, Tuple Spaces,… Transport
© Tammo van Lessen , Frank Leymann

19. Why Orchestration?
???
To achieve a business
goal, you often need
more than one service…
Which to use, in which
order, how to use them?
© Tammo van Lessen , Frank Leymann

20. Web Service Orchestration
BPEL!
© Tammo van Lessen , Frank Leymann

21. Process-based SOA
Messages / Conversations
ESB / WS Gateway
PI PI PI
PI PI PI
PI PI PI
PI PI PI
PI PI PI
PI PI PI
PM PM PM
Process Engine
© Tammo van Lessen 22

22. The Programming Models
Application
Processes
Programming in
the Large
Business Workflow
System
Service Configuration
Deployment pL EPR Service Bus
pT
Programming in
IT
Web Services
Service
the Small Container
© Tammo van Lessen

23. BPEL Concepts
© Tammo van Lessen 24

24. What is BPEL?
 Business Process Execution Language
 7/02 IBM & MS, 5/03 +BEA+SAP+Siebel, 4/07 OASIS Standard
 High-level programming language
 Recursive Model
 BPEL has native support for
 Long running processes
 Scalability
 Concurrency
 Message and instance correlation
 Fault handling
 Compensation based recovery
 Phoenix behaviour
 Most important: BPEL is standard and supported by most important
vendors.
 Defined Execution Semantics
 Abstract Processes (protocols, “views” on internal processes)
© Tammo van Lessen 25

25. BPEL 2.0 Activities
Basic Activities Structured Activities
receive reply invoke A flow pick
B C M1 M2 … A
assign validate
sequence forEach
1. 2. … N. 1. 2. … N.
throw rethrow exit
while if-elseif-else
c1 c2
compensate compensateScope c …
repeatUntil scope
wait
c
empty
extensionActivity
© Tammo van Lessen

26. BPEL Concepts: Variables & Partner Links
 Variables
 Shared variables, statically typed via WSDL messages, XSD elements or
XSD types
 “Global” process variables and “local” scoped variables
 Partner Links / Partner Link Types
 Partner Links define “contract channels” between partners
 Mutual call-back dependency
 Associates interfaces (pTs) with roles
 Partner Links define which partner takes which role
Key concept to enable asynchronous messaging!
Role 1 / myRole Role 2 / partnerRole “I expect from my partner
an implementation of this!”
portType portType
© Tammo van Lessen 29

27. BPEL Concepts: Fault Handling & Compensation
 Fault Handling
 Like in Java, enables alternative execution paths
 Can trigger compensation
 Compensation
 ACID Transactions are not applicable when dealing with
long running processes
 Compensation-based recovery
 Compensation Handler can reverse the work performed by an
already completed scope
 Compensation Handler is “installed” after successful execution of a
scope
 Compensation can only be triggered by
fault/compensation/termination handler of the enclosing scope
© Tammo van Lessen 30

28. BPEL Concepts: Fault Handling & Compensation
© Tammo van Lessen 31

29. BPEL Concepts: Data Manipulation
 (Strong type system)
 No explicit data flow
 Assigning variable values
 By receiving a message from a partner service
 By invoking a partner service and storing the result into a
variable
 Copying (parts) of variables into other variables
 <assign>
 Drawbacks: Quite cumbersome, requires often XSLT
Look at E4X and BPELJ
© Tammo van Lessen 32

30. BPEL Concepts: Modelling Styles
 Block structured modelling
 Nesting of structured activities
 Use of <flow> activity for parallelism
 Graph based modelling
 <flow> activity with links t1 t2
 Transition conditions & join conditions j
 Dead-Path-Elimination
 Acyclic graph to ensure sound execution
semantics
 Loops can be realized with <while> /
<repeatUntil> / <forEach>
© Tammo van Lessen 33

31. Message Correlation
 How can a messages be routed to the correct
process instance?
 A process instance is assigned one or more keys
 Business data is used as key
Process 4
(0123,15)
customerID
Process 3
orderNumber (0815,42)
Process 2
Message 1 (4711,37)
Process 1
4711 37 (0815,12)
Message 2
0815 42
© Tammo van Lessen 34

32. BPEL Extensions
 BPEL4People/WS-HT  BPEL4SWS
 Support for Human  Support for Semantic
Tasks Web Services (Service
 Standardization almost Discovery)
done
 Data Mediation
 BPEL-SPE
 BPELlight
 Support for sub-
processes  WSDL-less BPEL
 Autonomy is key  Is about message
 BPELJ exchanges
 Use Java in BPEL  BPEL JS/E4X
Activities  Use JavaScript/E4X for
 Use Java types in BPEL variable assignments
© Tammo van Lessen 35

33. Summary
 Process-oriented thinking is key to benefit from
service orientation
 on a business level
 on a technical level
 recursive aggregation model helps to support any
granularity
 BPEL is
 best suited for technical service orchestrations
 tailormade for WS-* based environments
© Tammo van Lessen 36

34. Apache ODE
© Tammo van Lessen 38

35. Apache ODE: Project Stats
 Open Source (Apache)
 ODE is widely deployed and being used in commercial
projects
 Intalio|BPMS
 WSO2 BPS
 Redhat/JBoss RiftSaw
 Progress Fuse ESB
 BPEL compliance
 Supports BPEL 1.1 & BPEL 2.0
 http://ode.apache.org/ws-bpel-20-specification-
compliance.html
 Runs on different platforms with different databases
 Interoperable with existing tools
© Tammo van Lessen 39

36. Apache ODE: Features
 Fast and scalable process engine
 Modular design & embeddable
 Lightweight ESB included
 Supported protocols: SOAP via HTTP/JMS/SMTP/what ever
Axis2 can do, POX/HTTP
 Implicit Message Correlation
 Via SOAP headers and WS-Addressing
 Different deployment scenarios
 JBI, hot-deployment
 Robustness
 Everything is internally executed within JTA/XA transactions
 Management and Auditing
© Tammo van Lessen 40

37. Apache ODE: Architecture
 Modular and extensible
Deployment *.bpel, *.wsdl,
architecture Unit deploy.xml
 Deployment Strategy
Apache ODE
 Integration Layer BPEL
OModel
Compiler
 Process and Instance
Management
BPEL Runtime
 Data Access
Axis2
 Scheduler
Management &
JACOB DAOs
JBI
Events
 Event Processor SCA
Hiber Open
Scheduler
 Transaction Manager … nate JPA
 Expressions
DB
© Tammo van Lessen 41

38. Thank you for
your attention!
Questions?
© Tammo van Lessen 42