WS-BPEL 2.0 versus BPEL 1.0

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