WS-BPEL 2.0 versus BPEL4WS 1.1

BPEL4WS 1.1 was contributed to the OASIS WS-BPEL Technical Committee, where it was advanced through an open process. The following list summarizes the major changes the Committee incorporated in WS-BPEL 2.0.

Data Access

Variables can be declared using XML schema complex types
XPath expressions are simplified by using the ‘$’ notation for variable access, for example, $myMsgVar.part1/po:poLine[@lineNo=3]
Access to WSDL messages has been simplified by mapping directly mapping WSDL message parts to XML schema element/type variables
Several clarifications have been added to the description of the <assign> activity’s <copy> semantics
The keepSrcElementName option has been added to <copy> in order to support XSD substitution groups or choices
The ignoreMissingFromData has been added to automatically some of <copy> operation, when the from data is missing.
An extension operation has been added to the <assign> activity
A standardized XSLT 1.0 function has been added to XPath expressions
The ability to validate XML data has been added, both as an option of the <assign> activity and as a new <validate> activity
Variable initialization as part the of variable declaration has been added

Scope Model

New scope snapshot semantics have been defined
Fault handling during compensation has been clarified
The interaction between scope isolation and control links have been clarified
Enrichment of fault catching model
A <rethrow> activity has been added to fault handlers
The <terminationHandler> has been added to scopes
The exitOnStandardFault option has been added to processes and scopes

Message Operations

The join option has been added to correlation sets in order to allow multiple participants to rendezvous at the same process with a deterministic order
Partner link can now be declared local to a scope
The initializePartnerRole option has been added to specify whether an endpoint reference must be bound to a partner link during deployment
The messageExchange construct has been added to pair up concurrent <receive> and <reply> activities

New Activities

Added serial and parallel <forEach> with optional completion condition
Added <repeatUntil>
Added new extension activity
Changed <switch> to <if>-<elseif>-<else>
Changed <terminate> to <exit>
Differentiate different cases of <compensate> by renaming them to <compensate> and <compensateScope>

Miscellaneous Changes

Added repeatEvery alarm feature to event handlers
Clarified resources resolution (e.g. variable, partner link) for event handlers
Added formal <documentation> support
Added extension namespace declarations in order to specify what extension must be understood
Add <import> support to import WSDL and XSD formally

Abstract Processes

Clarified Abstract Process usage patterns
Introduced Abstract Profiles to address different needs in Abstract Processes, and two profiles “Observable Behavior” and “Process Template” listed in the specification