Messaging

1
Messaging Web Services an Architectural View

• John Arnett, MSc
• Standards Modeller
• Information and Statistics Division
• NHSScotland
• Tel [phone] (x2073)
• mailtoJohn.Arnett_at_isd.csa.scot.nhs.uk
• http//isdscotland.org/xml

2
Contents

• XML Usage
• XML Applications
• Messaging and Web Services
• Interaction Models
• Message Construction

3
XML Usage

• Key features

• Human readable
• Structured and searchable
• Separates data from presentation
• Self-describing
• Extensible any number of tags allowed
• Meta-markup language

4
XML Usage

• Open standard, promoted by many vendor-neutral
  organisations, incl.
• W3C
• OASIS (Organization for Structured Information
  Standards)
• HL7 (Health Level 7)
• OMG (Object Management Group)
• UK Government

5
XML Usage

• Widely supported by software vendors and open
  source groups, incl.

6
XML Applications
Data Storage Content Management
7
Messaging and Web Services

• XML Messages
• Ideal for data interchange
• Text based
• Open
• Self describing
• Extensible
• Exchanged between applications on the same
  network or over the Internet/Extranet

8
Messaging and Web Services

• Web Services
• Set of emerging standards, incl. SOAP, WSDL and
  UDDI
• Allow systems to communicate over the internet
  using XML messages
• Used for
• remote service requests/calls
• enterprise application integration
• business process integration

9
Messaging and Web Services

• SOAP
• Lightweight, XML-based protocol for exchanging
  information over the internet
• Language, platform and transport independent
• v1.2 W3C Recommendation

10
Messaging and Web Services

• WSDL (Web Services Definition Language)
• XML-based language for describing services
  available on the internet

• UDDI (Universal Description, Discovery and
  Integration) directory services
• Information Services
• Operations

11
Interaction Models

• Message Channel

Message
Channel
Sender
Receiver
12
Interaction Models

• One-way (fire-and-forget)
• non-blocking, asynchronous model

Consumer
Provider
13
Interaction Models

• Synchronous Request/Response
• RPC

Consumer
Provider
14
Interaction Models

• Call Back
• Asynchronous conversations

Consumer
Provider
15
Interaction Models

• Telephone-like Post Office-like
• Synchronous Asynchronous
• Tighter coupling Loose coupling
• Strongly typed Document-based
• Fast feedback Slower feedback -
  call-return - queuing and routing

RPC Message-oriented
16
Interaction Models

• Point-to-Point
• One input channel to one output channel
• Message sent to 1 receiver only
• Message sent directly or via router/queue

17
Interaction Models

• Multi-Point
• One input channel to many output channels or
  subscribers
• Copy of message sent to each subscriber
• Message published via router / topic

18
Message Construction

• Document - transmits structured or unstructured
  data
• Command - specifies a function or method to
  invoke on the receiver
• Event - notifies receiver of some event of
  interest, e.g. an acknowledgement

• Message Types

19
Message Construction

• High Level Information Model
• HL7 v3 RIM
• CEN (European) Standards
• e-GIF (UK Government)

20
Message Construction

• Message Content
• Clinical guidelines, e.g. SIGN
• National Data Definitions, e.g. SMR
• Consultation with user groups, professional
  bodies and manufacturers
• Other sources, e.g. existing EDIFACT messages

21
Message Construction

• Standard XML Vocabularies
• Health Care
• NHSS architectural schemas
• Health Level 7 (HL7) v3
• Government
• UK GovTalk schemas
• International
• UNeDocs Code Lists XML - units of measurement, etc

22
Message Construction

• Message Schemas
• Messages
• Referral
• Waiting Times
• Message Structures
• NHSS
• HL7 CDA
• Government Gateway

23
Message Construction
24
Find Out More

• Scottish Health and Community Care XML Steering
  Group
• www.isdscotland.org/xml
• SCI XML Standards
• www.show.scot.nhs.uk/sci
• GovTalk Schemas and Standards
• www.govtalk.gov.uk
• Health Level 7
• www.hl7.org

25
Messaging and Web Sevices

• W3C Web Services Activity
• www.w3.org/2002/ws
• Web Services Interoperability
• www.ws-i.org

26
Communication Models

• WS-I Usage Scenarios
• www.ws-i.org/SampleApplications/
• SupplyChainManagement/2003-04/
• UsageScenarios-1.01-BdAD.doc
• Enterprise Integration Patterns
• www.enterpriseintegrationpatterns.com