Dr. Minder Chen

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Building XML Web Services for E-Business
Applications

• Dr. Minder Chen
• Associate Professor of Decision Science and MIS
• George Mason University
• Email MCHEN_at_GMU.EDU
• 703-993-1788

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Blinds and Elephants Though each was partly in
the right, and all were in the wrong!
It moves air like a fan.
It is massive as a wall.
It is sharp like a spear.
It is sneaky like a snake.
It is soft like a rope.
It stands solid like a tree.
Elephant illustration (c)2002 Jason Hunt
naturalchild.org/jason
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Diversified Views on Web Services
Business Processes Services
It moves air like a fan.
XML, SOAP, WSDL, UDDI
It is massive as a wall.
Web services?
Modularized ASP, WS Grids
It is sharp like a spear.
EDI, XML, B2B, SCM
It is sneaky like a snake.
Programmable Web
It is soft like a rope.
RPC, Corba, RMI, DCOM
It stands solid like a tree.
Elephant illustration (c)2002 Jason Hunt
naturalchild.org/jason
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Definition of Web Service

• Loosely coupled, reusable software components
  that
• semantically encapsulate discrete
  functionality and are
• distributed and programmatically accessible
  over standard
• Internet protocols.
• Web services are a stack of emerging standards
  that
• describe a service-oriented, component-based
  application
• architecture.
• Web services represent a model in which
  discrete tasks
• within e-business processes are distributed
  widely
• throughout a value net.
• -- The Stencil Group

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Where Is the Web going?
Static Content Web

• HTML
• Dynamic HTML (JavaScript)

• CGI (using Perl, etc.)
• ColdFusion, ASP, Java Servlet, JSP
• ASP.NET
• XML (Document interchange)

Dynamic Interactive Web
Integrated Programmable Web

• XML
• Web Services (SOAP, WSDL, UDDI)

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Evolutions of IT Applications
Web sites (Content-oriented)
C/S Applications (Transaction-oriented)
Enterprise Software Systems
Web-based Applications
Service-Oriented E-Business Applications
Web Services (Distributed Computing
Component-based development CBD )
Electronic Commerce (B2B EDI XML)
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Distributed Computing

• Remote Procedure Call (RPC)
• Message Queue
• IBM QSeries(IBM)
• Message Queue (Microsoft)
• Common Object Request Broker Architecture (CORBA)
• Distributed Common Object Model (DCOM)
• Java Remote Method Invocation (RMI)
• J2EE - Enterprise Java Bean

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HTTP and Firewalls
DCOM Service
U
Web Service
Client
Port 80
U
RMI Service
Firewall
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XML Standards

• XML definition
• languages
• XML 1.0
• XML Schemas

XML Parsers
XML/XSL Applications

• DOM
• SAX

• XML DTD files
• XSD files

Validation

• Generated
• Documents
• formatted in
• HTML CSS
• XML
• WML

XML documents
XSL Standards
XSL files
Standard XML software
Application files
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SOAP

• SOAP "Simple Object Access Protocol
• XML-RPC
• SOAP 1.1
• SOAP 1.2 (Working Draft)
• XML-based lightweight protocol for exchanging
• information in a decentralized, distributed,
  heterogeneous environment
• Encapsulates the ability to make RPC Calls
• Data Encoding (serializing and de-serializing)
• Message Structure
• Message-Processing

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XML Web Service Lifetime
Phase 2 Deserialize
Phase 1 Serialize
SOAP request
HTTP Header
SOAP Envelope
Attachments
Proxy object
XML Web Service object
Client
Web Server
Phase 3 Serialize
Phase 4 Deserialize
SOAP response
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SOAP Encoding Complex Data
ltsoapEnvelope ...gt ltsoapBodygt
ltGetStockResult xmlns"http//tempuri.org/"gt
ltresultgt ltNamegtWeb Service Inc.lt/Namegt
ltPricegt66lt/Pricegt ltTickergtWSIlt/Tickergt
lt/resultgt lt/GetStockResultgt lt/soapBodygt lt/soap
Envelopegt
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Develop Deploy Web Services
Web Services Provider
WSClass.Method() as ReturnedDataType


Web Services Application Server
VS.NET
Add Web Ref HTTP/WSDL
Web Service Source Code (Server)
HTTP-SOAP-IN Message
Web Service Executables
HTTP-SOAP-OUT
Deploy
WSDL
.NET Client Platform


VS.NET
Web Services Consumer
Web Service Proxy Code (client)
Web Service Proxy Code
Compiler
Client Source Code
Client Application
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• Service
• Registries
• Public UDDI
• Private UDDI

Find
?
Search criteria for web services
Publish
Business services info. URL to WSDL
WSDL URLs
?
?
Bind
?
Web Service Providers
WSDL URL
Web Service Consumers
WSDL File
?
?
SOAP Request
SOAP Response
?
Invoke
Role Operation Data flow
Data/Message
n
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Web services in the context of a Three-Tier
Application Architecture
Presentation Layer
Middle-Tier Layer
Server Resource Layer
XML
Windows Applications
Distributed Midle-Tier Components
Distributed Midle-Tier Components
Data Bases
Distributed Middle-Tier Components
.NET Framework Runtime Or Java Runtime
Environment (JRE)
Web Applications
Web Services
Web Services
Other Server Resources
Web Services
Mobile Web Applications
PDA Pocket PC
Legacy Applications
.NET CF J2ME
Web Services
Web Services
Web Services
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What is .NET Industry View
Software that connects people, information and
devices
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SOAP

• The SOAP Envelope is a XML-based message format
• HEAD
• BODY
• Bindings for exchanging SOAP envelopes
• HTTP-SOAP, HTTP-GET, HTTP-POST
• SMTP
• FTP
• Messaging queuing

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Web Services Standard Stack Reference Model
Service Composition (BPEL4WS)
Service Directory (UDDI)
Service Description (WSDL)
Standard Definition Languages (XML 1.0
Specification and XML Schema)
Messaging Protocol
Security (SAML, WS-Security)
Management (WS-Manageability )

SOAP Extension Reliability, Transaction (WS-Reliab
leMessaging, WS-Transaction)
(SOAP)
Communication Protocol (HTTP, FTP, SMTP, etc.)
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E-Business Integration Imperatives
B2C
Trading Partners Suppliers Distributors Business
Partners
Consumers
B2B Integration
REQUIREMENTS Standards based integration Configura
ble across applications Business process
oriented Loosely coupled Supports an incremental
approach Scaleable, available, secure, manageable
EAI
Heterogeneous Platforms ERP Application
Packages Proprietary Apps Legacy Applications
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compete / cooperate
Standard Organizations
Participate via contributing some IPs
develop
Open standards
Participate via giving feedbacks on practical
usefulness
support
adopt
Propriety standards
Development tools Infrastructure systems
Applications IT Infrastructures
use
develop
develop
IT Users
IT Vendors
Influence standards adoption
compete/ cooperate
Figure 20. Ecology of Standard Development and
Adoption
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Driving Forces

• Standards and
• Stakeholders
• IT Product Vendors
• Systems Integrators
• Enterprise Customer
• WS Providers
• Standard Organizations
• Web services standards

• Decision Outcomes
• Targeted applications
• Technical architecture
• Development strategies
• Deployment strategies

Web Services Adoption Implementation Decisions

• Technical Factors
• Application architecture
• Infrastructure tools
• Development tools

• Perceived Benefits
• Technical benefits
• Business benefits
• Operational benefits
• Strategic benefits

Driving Forces of Web services adoptions and
decision
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IT User Community
Needs for better faster development
deployment environments
Competing standards proposals
Requirements for applications integration
Systems Integration Firms or Internal IT Units
Standard Setting Organizations
IT Products Vendors
Enterprise IT Users
Integrated applications
Advanced integration skills and solutions
Web services development tools and
infrastructure products
Web services standards
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• The relatively rapid Web services adoption rate
  may be contributed by the following factors
• IT vendors are strongly endorsing of Web services
  standards.
• The cost of adopting Web services is marginal.
• Web services has a relatively smooth learning
  curve comparing to other distributed computing
  technology.

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Justification for Web service adoption Technical
and business benefits
Link to
Technical benefits
Business benefits