Architecture Working Group Andrew Jacobs

Introduction The AWG has been examining two separate but related issues: –Having the root node express the message type would make messaging easier to understand and the documents easier to process e.g. –Using type substitution on the FpML element is incompatible with WSDL based WebServices

Modelling Issues Many XML design tools don’t show types that can be substituted –Looking at the FpML element shows an empty element –Have to find message types in a long list of complex types XML binding tools have poor support type substitution –XML parsing and XSLT processors are fine Note however: –Type substitution is currently also used in FpML for block trade identifiers. –It is used by a number of firms to introduce extended types into FpML documents

The WSDL Problem WSDL interfaces are defined in terms of elements –Type substitution within the element is not allowed The W3C were queried and did not support a change to the WSDL specification to allow it.

WSDL Conclusions WSDL documents can contain their own schema definitions to create elements from imported types –Elements for method parameters can be created within the WSDL as needed. e.g Using FpML types in WSDL interfaces ties it to a single specific version –Service providers would want probably support several versions simultaneously –Possibly ‘string’ based to allow any XML to be passed

First Vote Changing the root element was first voted on in January along with 3 other issues –Fewer options where considered than latest round –Some uncertainty around the options –Voting was tied It was decided to look at the problem again, see what some other standards do, and re-vote –Brian Lynn asked to produce a paper

Patterns in Other Standards ISO Discrimination by namespace – … FixML – Discrimination on inner element – … Acord – Three different payload types – - Generic structure similar to an FpML DataDocument – - A generic business process messaging framework, similar to FpML’s messaging framework. – - Contains information following the Society of Actuaries ACORD tabular standard. Also examined ebXML & SOAP

Summary All of the standards identified above use a single, standard element name as their entry point. –ACORD has three but these appear to be in effect for different standards –In some of the cases (e.g. FIXML, FpML) this element name is based on the standard’s name; –In most cases (especially the more horizontally-oriented standards) this element name is generic (e.g., “Document”, “definition”, “envelope”, etc.) Only FpML makes use of xsi:type for defining document/message structure. Other methods used for defining document/message structure include –substitution groups (FIXML), –distinct namespaces and schemas (ISO 20022), –a transaction code (ACORD), and –single standard structure with optional elements (WSDL 1 and 2, SOAP).

Expanded Set of Options (A) No change – (B) New wrapper element containing FpML – … (C) Substitution group with FpML – … (D) Message type as a value field – messageType … (E) Root element name indicates message type – …

May Voting – 7 to 3 MemberAffiliation#1#2#3#4#5 Andrew JacobsHandCodedACEBD Andrew ParryJPMCECBDA Andrew CoatesMiley WattsECABD Brian LynnGlobal eMarketsACDEB Dominic MackenzieBGIEABCD Marc GratacosISDAECBDA Matthew RawlingsJPMCECBDA Raj PatelHSBCECDBA Simon HeinrichC24ACDEB Steve Ross-TalbotHat Trick SoftwareEABCD Henri PegeronDTCCACEDB DTCC vote received after cut-off.

Modifications to Rules of Operation Currently doesn’t allow a change to: –The root element, or –FpML version attributes Both need to changed –To allow multiple root elements –Make version attribute more FpML specific e.g. fpmlVersion Requires Standards committee approval.

Related Work Changes will require updates to: –Architecture specification –Messaging specification –Schemas –Examples & test cases Other 5.0 features are scheduled for the summer but implementation may take longer –Delay 5.0 or release later as 6.0? –Can’t be 5.1 as changes are not backwards compatible Changes will affect virtually all FpML implementations