WEB Services Test Marking Guide

Transcription

1 Time 40 min Total marks 40 WEB Services Test Marking Guide Answer any 5 questions(each worth 8 marks) If you do more that 5 only the first 5 (as they appear in the book) will be marked. 1. Question Give a definition of Web Services. Provide an insight of the W3 consortiums vision for Web Services, and the value it provides for business activities on the web. Answer: Web Services connect computers and devices with each other using the Internet to exchange data and combine data in new ways. The key to Web Services is on-the-fly software creation through the use of loosely coupled, reusable software components. Software can be delivered and paid for as fluid streams of services as opposed to packaged products Business services can be completely decentralized and distributed over the Internet and accessed by a wide variety of communications devices. The dynamic enterprise and dynamic value chains become achievable and may be even mandatory for competitive advantage. Provide a means to expose business functions as automated and reusable interfaces Provide a uniform mechanism for enterprise resources and applications to interface with one another. Offer business investment protection by allowing a business resource wrapped in a web service interface to be replaced without impacting the consumer of the web service Outline benefits to service provider, customer, and integration platform provider.

2 2. Question Provide a complete description of a B2B model, what are the likely services that would be offered what are the challenges and how would the data flow be described? Answer: The B2B model Tier 1 Interface / Interface Logic Interface / Business Logic Mediator Tier 2 Business Logic Tier 3 Database / Database Logic Services Procurement, Customer Relationship Management (CRM), billing, accounting, human resources, supply chain, manufacturing.

3 Chalenges Interaction. Interaction is the interoperation and integration with both internal and external enterprise applications. B2B applications are composed of autonomous, heterogeneous, and distributed components. Problem of Interactions among loosely coupled and tightly coupled systems. Area of research in databases, knowledge-based systems, and digital libraries. Applications Virtual malls, Loyalty Schemes Customized news delivery, Traffic monitoring, Route planning.

4 3. Question Explain the WSDL Layer, what is its role, how is it implemented, give a diagram to show how a service might have more than 1 interface. Answer The Layer WSDL is written in XML WSDL is an XML document WSDL is used to describe Web services WSDL is also used to locate Web services Definition Web Services Description Language (WSDL) provides a model and an XML format for describing Web services. WSDL enables one to separate the description of the abstract functionality offered by a service from concrete details of a service description such as "how" and "where" that functionality is offered. [W3C] what is WSDL For our purposes, we can say that a WSDL file is an XML document that describes a set of SOAP messages, and how the messages are exchanged. WSDL is XML, it is readable and editable, it is generated and consumed by software Diagram of WSDL

5 4. Question What is SOA give the basic principles involved Answer: The SOA is the basic architecture used by most RPC-style middleware systems. A service is an application that exposes its functionality through an application. A resource that is designed to be consumed by software rather than by humans. service implies service-oriented architecture (SOA). The Web Services architecture is based upon the interactions between three roles: Service provider, Service registry, Service requestor The interactions involve the: Publish operations Find operation Bind operations.

6 5. Question What facility is provided by the UDDI layer in the web services stack? Answer UDDI is an industry initiative to enable businesses to quickly, easily, and dynamically find and transact with one another UDDI enables a business to: describe its business and its services, discover other businesses that offer desired services, and integrate with these other businesses. A public registry Developed a specification based on open standards and non-proprietary technologies to solve the challenges associated with publishing Web services. Stores information about businesses and their services. One can publish and discover information about a business and its Web Services. This data can be classified using standard taxonomies so that information can be found based on categorization Contains information about the technical interfaces of a business's services. can interact with UDDI through a set of SOAP-based XML API calls. This can occur at both design time and run time to discover technical data, So that services can be invoked and used. Hosted by multiple operator nodes at no cost. Serves as infrastructure for a software landscape based on Web Services.

7 6. Question WSFL is based on Flow models Give a description of Flow Models and the role of WSFL. (You are not required to give a detailed discussion of WSFL) Marks: 8 Answer: We are looking at the notion of ordering (orchestration and Choreography) of activities In WSFL, flow models are used for the specification of complex interactions of services A flow model describes a usage pattern of a collection of available services, so that the composition of those services provides the functionality needed to achieve a certain business goal IE the composition describes a business process. The flow model specifies precisely how those services (steps in the flow) are combined, specifying in which order they have to be performed (including the possibility of concurrent execution), the conditional logic deciding whether an individual step or a group of steps have to be performed at all or should be looped, and the passing of data between the involved steps.

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