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2006 IEEE International Conference on Web Services ICWS 2006. Overview. Contents. Introduction to Web Services SOA WS-* Standrads Amazon Web Services Complex Events Processing. Introduction to Web Services. Web Services: W3C Definition. A Web service is a software system
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2006 IEEE International Conference on Web Services ICWS 2006 Overview
Contents • Introduction to Web Services • SOA • WS-* Standrads • Amazon Web Services • Complex Events Processing
Web Services: W3C Definition • A Web service is a software system • Identified by a URL, whose public interfaces and bindings are defined and described using XML • Its definition can be discovered by other software systems • These systems may then interact with the Web service • using XML based messages conveyed by Internet protocols
Web Services • Web services are an emerging technology that offer a solution for providing a common collaborative architecture • Web services provide functional building blocks which are not tied to any particular programming language or hardware platform • They are accessible over standard Internet protocols
The Evolution • Online systems replace Batch systems • Graphical User Interfaces replace “green” screens • Networked systems replace standalone systems • Internet based systems replace LAN based systems • Future ??? • Web Services replace simple Internet and LAN based systems
Web Services Technologies • XML (eXtensible Markup Language) • markup language that underlies most of the specifications used for Web services • SOAP (Simple Object Access Protocol) • (Simple Object Access Protocol), similar to JDBC, is a network, transport, and programming language and platform neutral protocol that allows a client to call a remote service. The message format is XML. • WSDL (Web services description language) • An XML-based interface and implementation description language. The service provider uses a WSDL document in order to specify the operations a Web service provides. • UDDI (universal description, discovery, and integration) • Both a client-side API and a SOAP-based server implementation that can be used to store and retrieve information on service providers and Web services.
How it works • A Web Service is a URL-addressable software resource that performs functions (or a function) • Web Services communicate using standard protocol known as SOAP (Simple Object Access Protocol) • A Web Service is located by its listing in a Universal Discovery, Description and Integration (UDDI) directory
Web Services Integration • In a lot of organizations, the data and logic of one application are basically useless to other applications • When an application and its data are isolated from other applications, we often say that they are in “silos” • Web Services are better at sharing data and functions • The result is that the “silos” come down, and previously isolated systems can talk to each other
Web Services Access • Web Services are especially good at providing access through different interfaces • A Web Service can have a dedicated client application, but it can also be readily accessed through browsers, wireless devices, voice-activated interfaces, and so on • Adding new access methods is much simpler than with a traditional application
Web Services Flexibility • One of the more important innovations in Web Services is “machine-to-machine communications” • This means that a Web Service can ask another Web Service to do something, and that Web Service can ask another Web Service to do something, and so on • In the future, many Web Services will really just be aggregations of other Web Services
Web Services Application Assembly • Future applications will be assembled from a diverse group of web services, aggregating functionality • Reusability is extended to the execution level, versus reusability from just the design and construction level
SOAP • Simple Object Access Protocol • SOAP is an open protocol specification defining a uniform way of performing RPCs using HTTP as the underlying communications protocol with XML for the data serialization.
How Is a Service Described? • WSDL (Web Service Description Language) • XML-based • W3C for standard
How Do I Find Web Services? • UDDI project by Microsoft, IBM, and others • Take a look at uddi.org • Websites • //www.xmethods.net • //www.salcentral.com
Using the Currency Exchange Web Service Currency Exchange WS RV Application Internet