About Business Process Execution Language?

Business Process Execution Language

1. Business Process Execution Language, platform independent, XML-based
2. A language to specify the behavior of business processes between Web services and as Web services
3. Contains process flow constructs for conditional branching, parallel processes, nested sub-processes, process joins, etc.
4. Uses WSDL to describe process interfaces so that they can be more easily integrated into other processes or applications.
5. Provided as an open standard under royalty free terms.

BPEL Goals:

1.      Platform independence – XML based language (Java, .Net implementations available)

2.      Services and Messages are first order citizens

3.      Provide an asynchronous programming model

4.      Leverage runtime metadata based interface like WSDL

5.      ‘Enterprise ready’ (security, transactional, reliable, scalable, etc.)

What's new in WS-BPEL 2.0?
1.    New activity types: repeatUntil, validate, forEach (parallel and sequential), rethrow, extensionActivity, compensateScope
2.    Renamed activities: switch/case renamed to if/else, terminate renamed to exit
3.    Termination Handler added to scope activities to provide explicit behavior for termination
4.    Variable initialization
5.    XSLT for variable transformations (New XPath extension function bpws:doXslTransform)
6.    XPath access to variable data (XPath variable syntax $variable[.part]/location)
7.    XML schema variables in Web service activities (for WS-I doc/lit style service interactions)
8.    Locally declared messageExchange (internal correlation of receive and reply activities)
9.    Clarification of Abstract Processes (syntax and semantics)
10.    Enable expression language overrides at each activity