SERVICE ORIENTED ARCHITECTURES

AND

WEB SERVICES

SOUMYALATHA .J

Agenda

Introduction to SOA Why SOA Architecture Web Services Standards Conclusion

SOA Definition

It is an IT approach in which applications make use of services available in a network

It involves developing applications that use services and making applications available as services.

Loose coupling between participating software agents.

Services

A service provides a specific function, typically a business function, such as analyzing an individual's credit history

A service can provide a single discrete function It can perform a set of related business functions, Services that perform a related set of business functions, as

opposed to a single function, - "coarse grained." Multiple services can be used together in a coordinated way. The aggregated, or composite, service can be used to satisfy a

more complex business requirement.

Service Oriented Architecture

Why SOA

Primary Benefits

Reusability Interoperability Scalability Flexibility Cost Efficiency

Web Services

The web services approach is based on a set of standards that are widely accepted and used.

This makes it possible for clients and services to communicate and understand each other across a wide variety of platforms and across language boundaries.

Types of Web Services

External – the request and the service belong to two different companies Risk of Security

Internal – the request and service are in the same company.

Web Services Standards

XML SOAP WSDL UDDI and ebXML WS-Security WS-BPEL

XML

XML has become the de facto standard for describing data to be exchanged on the Web.

As it's name indicates, XML is a markup language.

It involves the use of tags that "mark up" the contents of a document, and in doing so, describe the contents of a document.

An XML tag identifies information in a document, and also identifies the structure of the information.

XML - Example

<bookshelf>     <book>        <title>My Life and times</title>       <author>Felix Harrison</author>      <price>39.95</price> </book> </bookshelf>

SOAP

SOAP - Simple Object Access Protocol SOAP is an XML-based protocol for exchanging

information in a distributed environment. SOAP provides a common message format for

exchanging data between clients and services. The basic item of transmission - is a SOAP

message, which consists of a mandatory SOAP envelope, an optional SOAP header, and a mandatory SOAP body

SOAP

WSDL

WSDL – Web Service Description Language. A WSDL document contains information specified in

Web Service Description Language, as defined in the WSDL specification.

WSDL defines an XML schema for describing a web service.

To uncover the description for a Web service, a client needs to find the service's WSDL document.

UDDI

The Universal Description, Discovery, and Integration (UDDI) specifications define how to publish and discover information about services in a UDDI-conforming registry.

More specifically, the specifications define a UDDI schema and a UDDI API.

The UDDI schema identifies the types of XML data structures that comprise an entry in the registry for a service.

UDDI registry - "Yellow Pages" for web services.

WS-Security

It describes security-related enhancements to SOAP messaging that provide for message integrity and confidentiality.

WS-Security uses security tokens to enable SOAP message security and integrity.

Provides a general-purpose mechanism for associating security tokens with messages, and describes how to encode binary security tokens.

WS-Security is flexible and can be used with a wide variety of security models and encryption technologies, such as Public-key infrastructure (PKI) and Kerberos, as well as the SSL and TLS

WS-BPEL

WS-BPEL is (Web Services Business Process Execution Language), also identified as BPELWS, BPEL4WS, or simply BPEL

An XML-based language that is used to coordinate web services across a single business process.

It uses WSDL to describe the web services that participate in a process and how the services interact

Prior Service-Oriented Architecture specifications

DCOM is the acronym for the Distributed Component Object Model

CORBA - is the acronym for Common Object Request Broker Architecture

DCOM

An extension of the Component Object Model (COM).

Introduced in 1996 Designed for use across multiple network

transports, including Internet protocols such as HTTP.

DCOM is based on the Open Software Foundation's DCE-RPC spec.

CORBA

CORBA - acronym for Common Object Request Broker Architecture.

It was developed under the auspices of the Object Management Group (OMG). It is middleware.

The first service-oriented architecture for many people in the past was with the use of Object Request Brokers (ORBs) based on the CORBA specification.

The CORBA specification is responsible for really increasing the awareness of service-oriented architectures. 

Applications

FlightTracker is a good example; it can be integrated into management and refund systems for tracking frequent business trips

GetEarthLocation (06/15/2001), developed by a Solar Resource Institute, offers services to industries that use solar panels and helps them determine when energy generation is optimal.

Conclusion

SOA is a way of sharing functions in a widespread and flexible way.

Web services makes it possible for clients and services to communicate and understand each other.

Questions ?