Monday, 26 August 2013

web technology 2 marks


UNIT –I
1. Write about  the implementation of Web Service.
      A web service servlet accepts HTTP requests from clients and provides an HTTP
response for each request received. It expects that each HTTP request it receives will contain a SOAP XML document in the body of the request. This SOAP document specifies an operation to be performed by the web service and supplies input data for that operation.
                           
2. How client-server systems have more advantage than monolithic system?
    Advantages of client server systems
    Decomposition of system components.
    Separation of client from server.
    Encapsulation of data into the database server.
    Client does not know the physical layout of data.

3. Define interoperability.
   Interoperability is the ability of systems of using different platforms and languages to communicate with each other. Interoperability is achieved by supporting the protocol and data formats of the service’s current and potential clients.
   
4. Define web services.
     A web service is a software application identified by a URI, whose interface and bindings are capable of being identified, described and discovered by XML artifacts and supports direct interactions with other software application using xml based  via Internet based protocols.


5. Differentiate Service based development and Component-based development.
                                    Service based development          Component based development
Granularity                       Coarse                                         Medium                                        Contract                            Published                                    Public
Reusability                       High                                            Medium
Coupling                           Very loose                                  Loose
Dependencies                    Run time                                    Compile time
Communication Scope      Interenterprise                            Interapplication

6. Define Client/Server Architecture.
     Client server architecture is the client  which is used to make  the request   and  the server which give response to the requests.
      The client process retrieved the data from a server across a connection.

7. What is hub and spoke model?
    Each application that needs to communicate with each other must first send the message to the EAI hub which transforms and routes the message to the recipient on behalf of the sender.
    Sender and receiver uses different protocols.
  

8. List  the characteristics of SOA.
    The characteristics of SOA are
 Services are discoverable and dynamically bound
 Services are self-contained and modular
 Services stress interoperability
Services are loosely coupled
Services have a network addressable interface
Services are location-transparent
Services are composable.
Service oriented architecture supports self-healing.

9. What N-tier Development attempted  to do?
     N-tier development attempted to separate the layers of the application that presented the data to the user from the layers of the application that acted on the data in the database. It separates the presentation from the data manipulation logic.

10. What are the features of service model?
 The features of service model are
     Service abstraction
     Service encapsulation
     Service modularity
     Service polymorphism

11. Write the QoS specification.
The QoS specification contains the information such as
       Availability
       Accessibility
       Integrity
       Performance
       Reliability
       Regulatory
       Security

12. Define UDDI & WSDL.
     UDDI defines a platform independent framework for businesses to describe their publicly available services , discover the other services and share information about points of interaction in a global registry.
     WSDL is an XML format for describing network services as a set of endpoints operating on messages containing either document-oriented or procedure-oriented information.

13. Differentiate Application logic and Services logic.
    In the application scenario web services are building business-to-business and enterprise application integration applications from organizations.
    In the service scenario web service follows different implementation models such as simple service, composite service ,middleware service and service bus.

14.What are the different roles played by the application in SOA?
 The different roles played by the application in SOA are
       Service provider
       Service broker
       Service requestor

15.How the  client/server architecture is different from three-tier architecture?
     The client server architecture employs a simple client and a server in an enterprise system whereas the three-tier architecture employs a client side user interface, middle  tier and a backend data tier.
      The client server architecture redundantly copies the same business logic to call clients whereas the three tier architecture separates the business logic and all clients share a single implementation of business logic on the middle tier.

16.Define service contract.
    A service contract is a specification of the way a consumer of a service will interact with the provider of the service. It specifies the format of the request and response from the service. It requires a set of preconditions and post conditions.

17.Why we are using loose coupling in SOA?
     Loosely coupled modules have a few well known dependencies. A systems degree of coupling directly affect its modifiability. In a loosely coupled system the service consumer does not need detailed knowledge of the service before invoking it.

18.List out the layers in web services technology stack.
     Service Transport
     Service Messaging
     Service Registry
     Service Description
     Service Composition
     Standard Messaging

19. Write the features of  system architecture.
     System architectures are based on two-tier, three-tier or n-tier models.
     System architectures provide a distributed service framework to satisfy certain types of business needs.
    
20. Define SOA.
    Service oriented architecture is a special kind of software architecture which defines the service model derived from the object model. It has several unique characteristics such as discoverable and dynamically bound services, interoperability and lovation-transparent services.


21.What are Web Services used for?
Uses of Web Services:
               Middleware for distributed applications
               For remote procedure calls and data exchange
               Open standard based on XML
               For loosely coupled software services
               Independent of programming languages and operating systems
               Utilizing existing Internet protocols and server architectures

22. Define find ,bind and execute paradigm.
    The “find, bind and execute paradigm” allows the consumer of a service to ask a third party registry for the service that matches its criteria. SOA consists of six entities to support the find, bind and execute paradigm. The entities are service consumer, service provider, service registry, service contract ,service proxy and service lease.

23. What is service registry?
      A service registry is a network-based directory that contains available services. It is an entity that accepts and stores contracts from service providers and provides those contracts to interested service consumers.

24. What do you mean by service messaging?
     The messaging layer of the web services technology stack describe the data formats used to transmit data from one service to another over the transport. XML is the base format used for Web Services.

25.Define service proxy.
      The service proxy finds a contract and a reference to the service provider in the registry.It then formats the request message and executes the request on behalf of the consumer..The service provider supplies a service proxy to the service consumer.



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