Chapter 9. Integration into business processes 293
Documentation
The documentation is good, intuitive, easy to read and understand, and it is
readily available. In WebSphere Studio Application Developer Integration
Edition, click Help
→ Help Contents to bring up the Information Center. Select
WebSphere Studio on the left. Select Developing
→ Processes → The
Process editor (BPEL).
The online help contains detailed information explaining how to use the Process
editor, create processes, and set attribute values in the Attributes view of the
Process editor. It also explains concepts and describes all of the BPEL activities.
This is an excellent source of information that you should read before you start
developing your own business processes in the Process editor.
Note: Do not get a false sense of security that the tool will do everything for
you. Indeed, the tool does generate most (if not all in certain scenarios) of the
artifacts, components, and projects for you.
Rather than clients calling your business processes directly, in some situations
you might want to add another layer of abstraction between consumers of
your business process and the actual process. You might want to consider
doing common processing in a service end-point, such as request and
response handling, caching, security, adding your own custom SOAP
handlers, and so on.
Common architecture, design and implementation standards, principles , and
patterns must be adhered to. A principle concern should be stability through
interfaces. In a services-based architecture using Web services technologies,
you should layer your service end-points, typically using an interaction and
processing layer. Designing your service interface, and designing the
business process (service implementation) requires the same effort.
294 Managing Information Access to an EIS Using J2EE and Services Oriented Architecture
For additional online documentation on Business Process Choreographer you
can visit these sites:
???? WebSphere Business Integration Server Foundation Process Choreographer:
http://ibm.com/developerworks/websphere/zones/was/wpc.html
???? Process Choreographer Concepts and Architecture White paper:
http://ibm.com/developerworks/websphere/library/techarticles/wasid/WPC_Conc
epts/WPC_Concepts.html
Debugger
Using WebSphere Studio Application Developer Integration Edition, you can
debug your business processes by setting break points in Java snippet activities
and on control links, before or after some activities. The ability to debug your
BPEL business processes will help you to deliver robust processes. The
performance of the debugger at the time of writing this book is quite slow. You
would need a powerful development workstation with a lot of memory and
processing power to debug BPEL processes. This performance might affect your
project delivery if you are on a critical path and need to trace a problem using the
debugging tool.
Suggestion: Naming standards are especially important. Consider
documenting your naming standards before you begin to create your
processes projects in your development tool.
We suggest that you have naming standards for at least the following:
???? Service projects
???? EJB projects
???? Java and utility projects
???? Web projects
???? Package names
???? WSDL files
???? BPEL
– Business process names
– Process activities
– Process exception handlers
– Variables (or message definitions in WSDL files)
Behind the scenes, most of the projects, components, or artifacts are being
generated for you. If you or your project team must change names later in
your project, the effort to re-factor, re-deploy, and re-build could potentially
effect the delivery of your project.
Chapter 9. Integration into business processes 295
BPEL technology
If you have been implementing message flows in WebSphere Business
Integration Message Broker or process flows in WebSphere Business Integration
Workflow, then you are probably familiar with a lot of the concepts of BPEL
technology.
BPEL aims to provide a language that formally specifies business processes
based on Web services, thus extending the Web services interaction model to
support business processes. IBM have extended the standard BPEL
specification (sometimes referred to as BPEL+) to support Java snippet and Staff
activities.
Using a services-based architecture style, we exposed our components and
business processes using Web services technologies. We created composite
applications by using (or rather reusing) services. BPEL is crucial for business
process interoperability across Web services. Running business processes over
Web services is crucial for enterprise adoption of Web Services.
BPEL is best suited to provide the standards-based solution that addresses not
only business process representation and execution but also the sharing of
business processes across disparate systems. Business processes specified in
BPEL are fully executable and they are portable between BPEL compliant
environments. A BPEL business process interoperates with the Web services of
its partners, whether these Web services are realized based on BPEL.
BPEL is based on XML and WSDL. WSDL offers a very flexible binding
framework. SOAP over HTTP is only one binding. Other bindings allow
developers to reach out to EJB/RMI components, JMS destinations or even Java
objects without any performance degradation. The only constraint is that the
input and output parameters have to be describable using XML schema.
However, this is a very good constraint because it creates an important
abstraction which allows for better tooling.
For additional information about the specification, you can refer to the Business
Process Execution Language for Web Services Version 1.1 at:
http://ibm.com/developerworks/library/ws-bpel/
Definition: BPEL is an XML-based language for describing a flow of
messages across a set of services. Example:
???? First send message A to service A
???? Then wait until you receive message B from service B
???? Then tranform message B into message C
???? Then send message C in parallel to service D and Service F
296 Managing Information Access to an EIS Using J2EE and Services Oriented Architecture
Summary
At the time of writing this Redbook, the team used WebSphere Studio Application
Developer Integration Edition Version: 5.1.0 Build id: 20040319_0845 for
creating and testing our BPEL processes in the Process editor.
The Process editor tool is easy to use, if you understand the key concepts. Some
of the key concepts you must be familiar with are:
???? Flow- versus sequence-based BPEL processes
???? Which activities are available, when, where, how, and why you would use
each activity
???? Transactions and compensation handling
???? Correlation sets
???? Partner links
???? Variables
???? Exception handling
???? WSIF: if you want to invoke your business processes using the
BusinessProcess or LocalBusinessProcess session bean
You do have the ability to debug your BPEL processes, but at the time of the
writing of this book, the debugger performance was slow. It was quite a time
consuming process to trace a BPEL business process.
We expect that BPEL will continue to move forward and serve as the primary
foundational technology for executable business process descriptions. We also
expect that BPEL runtime environments and tools will move forward to provide a
efficient, effective, stable, and performant environment for business process
implementations.
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