Proposal for dynamic context for BPSS

["David RR Webber" <david@drrw.info>]

Monica,

 

As requested today, here is the text of the

context proposal.

 

Use Cases:

=========

 

Given that BPSS should:

 

a) support late binding of specific parameters within

    the BPSS based on business factors that

    occur during a BPSS use

b) support business modellers being able to

    identify critical factors during creation of a BPSS

    that effect linking and switching within a process

    and be able to specify those and quantify their

    details -

    (e.g. deliveryCountry = Mexico, USA, Canada).

c) support ability to configure BPSS flows to match

    locale or other factors globally based on context

    provided when a CPA is determined between

    participants based on their own transaction

    needs (e.g. produceType="mustRefridgerate")

d) provide context to external components that

    may be directed by BPSS - such as transaction

    handling software (Java, EDI Mapper, XSLT, CAM,

    EAI adaptor, et al), or web service step.

e) have a mechanism to determine pre-conditions

    for BPSS and outcomes - start, wait, or skip

    that allows implementers to configure when

    a BPSS should commence.

 

Approach:

=======

 

Provide an XML instance, separate from but

relating to the BPSS, specifically for managing

context, and link to that from BPSS either

directly (URL) or indirectly via reference in CPA

(CPA can provide link to constrained BPSS

 context set verified by collaboration

 participants as they define their CPA).

 

In constructing context rules within this XML

instance simple XML will be used along with

XPath expressions and a basic datatyping

system founded on the W3C foundation

data types.  This will be supplemented

with a limited set of string referencing

functions necessary to complete the

data model of context rule parameters.

 

The aim is to make this rapidly implementable

with off the shelf simple XML development

tools, and concise and complete to be specified

with a supplemental Context Technical Note

specification of 15 pages or less.  This

supplemental document will follow the model

used by the Registry team for their supplemental

notes to their main specifications.

 

Rationale:

=======

 

1) A well featured context mechanism will set

    BPSS V2.0 apart as the premier approach to

    business orchestration using the latest

    techniques for integration into the SOA

    solution stack.

 

2) The cost of documenting the technical

    note in 15 pages is comparable to

    defining a lesser capability within the

    existing BPSS with mostly the

    same effort (XPath expression

    definition and control mechanisms).

 

3) Setting this feature now for V2.0 will

    set the foundation for V3.0 and beyond,

    without requiring implementers to "two-step",

    (supporting a lesser V2.0 capability that

    then is extended later with attendent need

    to support two related mechanisms).

 

4) Having a consistent context mechanism

    that BPSS can use to manage not only

    its own needs but can be referenced by

    any other component that relates to the

    BPSS provides a single consistent

    system across the ebXML stack.

 

5) The context mechanism proposed is

    already known and therefore the level

    of effort and risk in designing it is

    significantly less than involved in

    starting with nothing. 

 

6) Having a well featured context

    system that is extensible ensures

    that all the use cases a) thru e)

    can be accommodated sufficiently

    in V2.0 - therefore significantly

    enhancing the value and utility of

    the BPSS specification.

 

Technical Detail:

============

 

The draft proposed initial Context Technical Note

document will be posted separately for

reference, but it is anticipated that this

will be completed as a work item for V2.0

and agreed to as part of that process, by

BPSS team members.  Input from all

6 use cases and worked examples can then

be generated as part of the deliverable too.

 

Thanks, DW.