1. BPEL4WS Business Process Execution Language for Web Services Jim Clark eBusiness Strategist

2. Agenda Evolution to Web Services Understanding BPEL4WS Using BPEL4WS
The need for business processes
Understanding BPEL4WS
BPEL4WS in a Nutshell
Abstract Processes
Simple Scenario
Using BPEL4WS
Implementing BPEL4WS
Quick walk-through
Typical BPEL4WS constructs
Update on the OASIS BPEL4WS Technical Committee

3. Evolution to Web Services

5. The Evolution to Web Services
Business Benefit
2000+
Web application
technology =
Web services
The Goal
A standards-based architecture that is broad yet flexible enough to provide secure, reliable, transacted Web services messaging infrastructure
Late 1990s
Web technologies appear
e.g. HTTP, HTML, XML
Early 1990s
Application integration technologies appear
Through 2002 and into 2003, the Web services landscape has evolved to meet customer demand:
- Interoperability
- Security and Policy
- Coordination, Transactions, Business Process
The goal: A standards-based architecture that is broad yet flexible enough to provide secure, reliable, transacted Web services messaging infrastructure
Pre-1990s
Custom, static
B2B Integration

6. Web Services Overview Internal Systems Your Company Customers Partners
XML
SOAP
SOAP
SOAP
Customers
Partners

7. Web Services Overview What’s Missing? Your Company Security
Reliable Messaging
Transactions

8. Good Progress…More To Do
Businesses need a model for describing how individual Web services can be connected to create complex, reliable and dependable business processes
This must enable...
Baseline transactional support
Interoperability between business processes and business partners in heterogeneous environments
Interoperability between tools such that any supporting tool can be used to author and analyze business processes
Executability in each supporting environment

9. Web Services “Secure, Reliable, Transacted”
Business Processes
Business Process Execution Language for Web Services (BPEL4WS)
Transactions
Reliable Messaging
Security
Quality of
Service
Description
Web Services Description Language (WSDL)
Messaging
Simple Object Access Protocol (SOAP)
Extensible Markup Language (XML)
Other protocols
Other services

10. “BPEL4WS in a Nutshell”
A Turing complete language that can be used to specify behavior of business processes
Between Web services...
...and as Web services
BPEL4WS is not a programming language
Exchange format for defining public behaviors (business protocols)
Export from one platform, import into another
BPEL4WS implementations leverage platform-specific strengths
Abstract processes
Specify constraints of message exchange
Exposes only information required by partner
Same language may also be used to define executable processes and business protocols
“Best practice” executable models?
We have discussed adding support for WSDL 1.2, but its too early at this point in time. (Same for XPath 2.0)
Every partner is assigned a unique endpoint reference

11. BPEL4WS Dependencies XML 1.0 W3C XML Schema 1.0 WSDL 1.1 XPath 1.0
WS-Addressing
Every partner is assigned a unique endpoint reference

12. BPEL4WS
Extends and subsumes previous specifications in this area published individually by Microsoft XLANG (05/01) and IBM WSFL (05/01)
XML-based workflow definition language
Describe business to consume/provide Web services in a reliable and dependable manner
Portability and interoperability by defining a set of constructs to implement executable business processes and to implement message exchange protocol

13. BPEL4WS – Basic Concepts
Peer-to-peer interaction between Web Services described in WSDL
Process and partners are modeled as WSDL services
BPEL4WS provides the process definition

14. What is an Abstract Process?
Description of public behavior
Public face of private processes
Independent of implementation
Scenarios:
BigCo dictates trading partner requirements
Industry consortia provides guidelines for working together
BPELa
Industry
Committee
BigCo
BPELa

15. Simple Scenario Goals:
Allow customers to submit travel itineraries to travel agents;
Automatically procure appropriate airline, hotel and vehicle reservations for customer itineraries;
Automatically return confirmation on all reservations back to the customer once processing of the itinerary is complete; and
Streamline cancellation procedure.

16. Simple Scenario
BPEL4WS: Define how to integrate the services of partners into business processes.
BPEL4WS: Define how specific activities of a business process can be exposed publicly as Web services, bridging the abstract and the executable.

17. BPEL4WS Expect most practical usage in
Design of business protocols (external behavior)
Design of best practices and templates (executable models)
Realistic process implementations will need platform-specific resources
Common model for “public” and “private” behavior
The boundary between private and public can shift
Outsourcing, mergers, etc.
Conformance relationships, export and import, is easier if the underlying set of core concepts is the same

18. BPEL and WSDL WSDL BPEL Port types, services and messages (extensions)
Defined abstractly
BPEL
Partner Links
Define partners, services
Variables
Globally visible, used to pass info, state, etc
Fault Handlers
Transfer of control during an exception
Activities
Process definition/description

19. What’s in BPEL4WS? Business Process Partner Links Variables
Correlation Sets
Partner links model relationships between partners
Fault Handlers
Activities

20. Correlation
Correlation identifiers are groups of properties embedded in messages
Correlation is used between partners to identify process instances
Different partners may use different correlation mechanisms
Even for a single partner correlation mechanism might change in course of interaction
Correlations can be based upon an XPath 1.0 query, but its also possible to use them with non-XML payloads such as EDI

21. Activities <-! activity can be any one of the following: -->
<empty>
<invoke>
<receive>
<reply>
<assign>
<wait>
<throw>
<compensate>
<terminate>
<flow>
<switch>
<while>
<sequence>
<pick>
<scope>

22. WSBPEL Technical Committee Update

23. About the WSBPEL TC Technical Committee launched 5/15/2003
BEA, IBM, Microsoft, SAP and Siebel submitted BPEL4WS V1.1 with royalty free terms
Subcommittees:
Issues
Specification Editing
Use Cases
Liaisons
Implementation
Liaisons with:
CEFACT Business Process WG
W3C Web Services Choreography WG
Others pending…
Publicly available:
Archives
Spec, Issues List, Resources
Comment “web form”

24. Recommended Resources
Start using BPEL today with BizTalk 2004
Download a trial copy
BPEL 1.1 specification (draft)
Goals of the BPEL4WS Specification
Abstract Processes in BPEL4WS
BPEL4WS Issues Tracking
BPEL4WS Use Cases
msdn.microsoft.com/library/en-us/dnbizspec/html/bpel4wsspecindex.asp

25. © 2003 Microsoft Corporation. All rights reserved.
This presentation is for informational purposes only. MICROSOFT MAKES NO WARRANTIES, EXPRESS OR IMPLIED, IN THIS SUMMARY.