1. Presentation 7: Part 1: Web Services Introduced

2. Outline Definition Overview of Web Services Examples Next Time: SOAP & WSDL

3. Web Service Defined W3C definition: [Definition: A Web service is a software system designed to support interoperable machine-to-machine interaction over a network. It has an interface described in a machine-processable format (specifically WSDL). Other systems interact with the Web service in a manner prescribed by its description using SOAP messages, typically conveyed using HTTP with an XML serialization in conjunction with other Web-related standards.] In reality: a very much more cloudy definition

4. Web services are many things SOAP & WSDL RESTFull XML-RPC JSON Other frameworks

5. Overview SOAP & Web services Simple Object Access Protocol: A light-weight & ultra heterogenic alternative to CORBA, DCOM & RMI Openness in focus Not meant in the role of large scale, transaction heavy communication (as CORBA & J2EE) Limited support for services for transactions, concurrency, persistence, scalability Does have Interface Definition Language for heterogeneity (WSDL) Fails on several of the dist. system requirements! Easy to implement yourself And many, many frameworks

6. Examples of Web Services Microsoft Mappoint – get adress information and GPS coordinates and maps from the web Google's Web Service - access the Google search engineGoogle's Web Service http://www.google.com/apis/ Amazon's Web Service - access Amazon's product informationAmazon's Web Service http://associates.amazon.com/e xec/panama/associates/join/dev eloper/resources.html XMethods - collection of information about existing Web servicesXMethods http://www.xmethods.com SalCentral - WSDL / SOAP Web services search-engineSalCentral

7. Service-Oriented Architecture Client Server Registry Abstract Architecture - Web service stack Abstract Architecture - Web service stack Legacy code on server Legacy code on server 1 1 2 2 3 3 Opening up for doing business (the sharing of services)

8. Technologies for SOA SOAP for communication WSDL for contract & binding UDDI & WSDL for registration & discovery