1. 1 Web Services Distributed Systems

2. 2 Service Oriented Architecture Service-Oriented Architecture (SOA) expresses a software architectural concept that defines the use of services to support the requirements of software users

3. 3 Service Oriented Architecture Service Requestor Service Provider Service Broker Legacy System Internet

4. 4 Requirements for a SOA Interoperability between different systems and programming languages Clear and unambiguous description language Retrieval of the service Security

5. 5 Web Services: Definition W3C 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 implement a Service Oriented Architecture

6. 6 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.

7. 7 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

8. 8 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.

9. 9 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.

10. 10 Technologies

11. 11 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. What are Web Services good for?

12. 12 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. What are they good for?

13. 13 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. What are they good for?

14. 14 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. What are they good for?

15. 15 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.

16. 16 How Is a Service Described? WSDL (“Web Service Description Language”) –XML-based –Submitted to W3C for standardization Terraserver example –http:terraserver.microsoft.com/default.aspx

17. 17 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

18. 18 XMethods

19. 19 Currency Exchange

20. 20 Using the Currency Exchange Web Service RV Application Currency Exchange WS Internet

21. 21 WebSphere Studio Wizards Wizards make it easy for you to create and use Web Services –Wizard to create a Web Service from a JavaBean Generates WSDL document Creates all required software components Create a Test client –Wizard to create a Web Service Client Use the WSDL document as input

22. 22 Generate a Web Service Client

23. 23 Web Service Client

24. 24 Web Service Client

25. 25 Testing Input.jsp Result.jsp Method.jsp

26. 26 conversion.html

27. 27 conversion.html <IFRAME src="Input.jsp?method=getRate"name="inputs" scrolling="no" frameborder="0" height="250"> <IFRAME src="Result.jsp" name="result" scrolling="no" frameborder="0">

28. 28 conversion.html

29. 29 Currency conversion

30. 30 Lab Exercises Create Web Services client Integrate Web Service into the RV application