12Web ServicesNew services provided by various Web service combinations
13ProtocolA protocol is like an alphabet or dictionary. It allows you to translate things.A protocol is open if the "translator guide" is available to anyone. It means that you can easily build a software that talk and understand this protocol. A closed protocol is a protocol for which the "translator guide" is not available. It means that only the company who developed the protocol can use it and build software using it.
18WSDL (Web Service Description Language) Role of WSDL in Web service use
19WSDL (Web Service Description Language) Composition of a WSDL document, including Web service URL in implementation component
20WSDL Document Data structures and data types are defined or referenced The logic encapsulated by the service is divided up and made available through service operationsSpecific messaging requirements are establishedNaming conventions are applied to the service interface itself
21SOAP (Simple Object Access Protocol) SOAP's features allow communication with Web services even if they are protected by firewalls
25Case StudyThis case study develops a web application that accepts place names, and returns a map showing a road route between the two places.Traditional Application Design
26Case StudyThis case study develops a web application that accepts place names, and returns a map showing a road route between the two places.Application Design using a Web Service ArchitectureThe development of this application has resulted in the deployment of a number of reusable services that can initiate the development of other applicationsThe architecture is scalable: even if all services were initially deployed on a single computer, if the server is swamped by heavy use, services can easily be migrated to different computersThe most suitable participant can provide the back-end services (e.g. the Atlas of Canada can provide the server that provides the base map).
28Technologies XML (eXtensible Markup Language) markup language that underlies most of the specifications used for Web services. SOAP (Simple Object Access Protocol)A network, transport, and programming language-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.
29How it worksA 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.
30Characteristics A Web Service is accessible over the Web. Web Services communicate using platform-independent and language-neutral Web protocols.A Web Service provides an interface that can be called from another program.A Web Service is registered and can be located through a Web Service Registry.Web Services support loosely coupled connections between systems.
31What are Web Services good for? 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.
32What are they good for? 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.
33What are they good for? 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.
34What are they good for? 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.