Presentation on theme: "BT User Experiences Jon Calladine 21st June 2005."— Presentation transcript:
BT User Experiences Jon Calladine 21st June 2005
BT Schema/Web Services evolution Enabling the Infrastructure Document Centric Services 3 rd Party Schema Going to Market
Enabling the infrastructure Wide industry support for the standards. Interoperability was achieved. –RPC encoded Code generation matched existing practice. –Productivity Heterogeneity conquered –Legs to the legacy Was a success because :
Enabling the Infrastructure - 2 Heavy emphasis on testing –TestBench Simplicity and restricted vocabulary Some technologies depended on annotations –SOAPENC,:arrayType, unbounded arrays Hadn’t fully embraced the concept of contract first coding. Versioning began to be an issue But...
35 systems >30 registered robots 20,000 ‘dumb’ screens CSS Copper Records migration BMS (COTS) BMS Hub Pub/Sub Document Centric: Bearer Mgt System 15 WS(MQ) 170k calls/hour DCE RPC RMI Corba SISS MQSeries IP 3270
Document Centric Objectives –Open re-usable services –Generic –Future proofed, Compliant = DocLit –Use of tools essential. (Range of clients + robots) Constructs not supported, unpredictable behaviour –xs:all, xs:choice Raised the bar on testing. We had to constrain the schema designers.
Document Centric - 2 Avoid date & time types Avoid user defined simple types Namespace qualify schema elements Always qualify schema references Use venetian blind style schema Nest repeated elements in their own container Avoid xs:choice, xs:all Use nillable=“true” & minOccurs= “0” for optional schema elements Toolkit Friendly Schema Vocabulary
3 rd Party schema Non determinism, Invalidation of the UPA rule Uses substitution groups extensively. –Toolkits don’t support this well Mixed Content elements –Incorrectly represented/rejected Result: we have departed from the spec. Service Provisioning Markup Language. OASIS Nov 2003
Going to Market Mass market, volume services Usable interfaces essential Deregulation, equivalence of input Not acceptable to support ‘best of breed’ only Current BT B2B/ebXML implementations do not publish schemas but.. Customers are clamouring for them …. –To assist in processing the documents
Summary The standard for describing Web service messages. Code binding is an expectation amongst developers. In our experience, XML Schema is implemented inconsistently in vendor tools, especially code generators. There already is a lowest common denominator ‘profile’. Practical interoperability testing is essential. Better test pack is required. –Working around interoperability issues with vendor supplied tools is difficult. Best Practices are required for a number of different aspects of schema e.g. Versioning.
C Q A X O N V Q J I D U A G T O X M A S N K X J R R X B C C M T A I C C T D D C S Z Z S B P X W L X P H A R S D T G R J L G A V U E P O E A R V B U J E Q W S B Q D Q I N W R S C O X U V Q N H U C L C E U R C R T A G P N E F J O C E H T O Z Y L V E N E T I A N B L I N D P I E C T Q T P W B T C R I N E F E A Q Z S C E U Y E G M W O Y F O P E L J A V H O N R R T O P C M N I L L A B L E T W E E L A W N L W E A V J X F D X I N A P U R U O N O H G R T XS:SEQUENCE XS:CHOICE HONOUR UPA COMPLEXTYPE MINOCCURS MIXEDCONTENT NAMESPACE QUALIFY NILLABLE VENETIANBLIND.