L8 - Technology Perspective of Service-oriented System Integration

Question 1

What are the goals of the lecture?

Answer 1

Explain Web service technology and its use in SoSI.

Explain RESTful service technology and its use in SoSI.

Question 2

What is the SOA principle of Contracts?

Answer 2

Services must have a common way to describe their interface, documents, and constraints.

Question 3

What is the SOA principle of Discoverability?

Answer 3

There must be means to find out which services are available.

Question 4

What is the SOA principle of Loose Coupling?

Answer 4

Dependencies between services, contracts, implementations, and consumers should be minimized.

Question 5

What is the SOA principle of Statelessness?

Answer 5

Services should not hold intermediate states in running instances to support scalability and reuse.

Question 6

What is the SOA principle of Composability?

Answer 6

Services should be designed to be repeatedly combined with other services.

Question 7

What are the standardized steps of Web Services?

Answer 7

Publish, Find, Bind.

Question 8

What are the standardized sub-technologies of Web Services?

Answer 8

XML, SOAP, WSDL, UDDI.

Question 9

What is XML in Web Services?

Answer 9

A data representation language used for exchanging information.

Question 10

What is WSDL in Web Services?

Answer 10

A contract description language that describes the service interface.

Question 11

What is SOAP in Web Services?

Answer 11

A text-based application protocol for sending and receiving messages.

Question 12

What is UDDI in Web Services?

Answer 12

An architecture for service discovery that catalogs and publishes WSDL descriptions.

Question 13

Why is XML used in Web Services?

Answer 13

It is a standard format for data exchange, middleware-independent, and forms the basis of WSDL, SOAP, and UDDI.

Question 14

What is WSDL?

Answer 14

An XML-based language that describes the interface of web services, including network addresses and operations.

Question 15

What are the three parts of a WSDL document?

Answer 15

Root – Service name and included standards.

Abstract interface – Service operations and messages.

Implementation interface – Binding of abstract part to message format, protocol, and address.

Question 16

What are the key elements of the abstract interface part in WSDL?

Answer 16

PortType: Specifies operations and messages.

Operation: Defines a function.

Message: Defines data exchanged, including input and output.

Question 17

What are the key elements of the implementation interface part in WSDL?

Answer 17

Binding: Binds operations to a transport protocol.

Service and Port: Define the service name and network address.

Question 18

What is SOAP?

Answer 18

A text-based protocol for exchanging messages in Web Services.

Question 19

What are the elements of a SOAP message?

Answer 19

Envelope: Identifies the XML document as a SOAP message.

Header (optional): Contains metadata like security and priority.

Body: Contains the actual message data.

Question 20

What transport protocols does SOAP support?

Answer 20

Originally designed for HTTP but can also use HTTPS and other protocols.

Question 21

What is UDDI?

Answer 21

A registry that allows service providers to publish services and consumers to discover them.

Question 22

What is the UDDI Invocation Model?

Answer 22

1. Provider registers the service.
2. Consumer searches for a service.
3. Consumer binds to the service.
4. Consumer invokes the service.

Question 23

What is a RESTful service?

Answer 23

A service that transfers resource representations over HTTP using a URI.

Question 24

What is a resource in RESTful services?

Answer 24

An object (e.g., product, customer, order) accessed at a unique URI.

Question 25

What are the four basic HTTP methods in REST?

Answer 25

GET POST PUT DELETE

Question 26

What does the GET method do?

Answer 26

Retrieves a resource. Example: GET /api/customers/2.

Question 27

What does the POST method do?

Answer 27

Creates a new resource. Example: POST /api/customers.

Question 28

What does the PUT method do?

Answer 28

Updates an existing resource. Example: PUT /api/customers/2.

Question 29

What does the DELETE method do?

Answer 29

Deletes a resource. Example: DELETE /api/customers/3.

Question 30

What is the role of media types in RESTful services?

Answer 30

Defines the format of data exchange between client and server.

Question 31

What are common media types in RESTful APIs?

Answer 31

application/JSON application/XML text/plain text/html

Question 32

How does RESTful services support the SOA principle of Contracts?

Answer 32

By applying defined HTTP methods and media types over a URI.

Question 33

How does RESTful services support the SOA principle of Discoverability?

Answer 33

Through resource URIs managed by IANA.

Question 34

How does RESTful services support the SOA principle of Loose Coupling?

Answer 34

The client-server architecture ensures separation of concerns.

Question 35

How does RESTful services support the SOA principle of Statelessness?

Answer 35

RESTful services do not maintain session states between requests.

Question 36

How does RESTful services support the SOA principle of Composability?

Answer 36

Limited composability as there is no explicit structuring.

Question 37

What are the key differences in architecture between Web Services and RESTful services?

Answer 37

Web Services: Rigid architecture with WSDL, heavyweight. RESTful: Simpler architecture based on REST principles, lightweight.

Question 38

What are the key differences in flexibility between Web Services and RESTful services?

Answer 38

Web Services: Supports multiple protocols, security, and reliability. RESTful: Supports different data formats (JSON, XML) with fewer constraints.

Question 39

What are the key differences in complexity between Web Services and RESTful services?

Answer 39

Web Services: Complex due to formal WSDL and SOAP definitions. RESTful: Simpler, relying on HTTP methods and resources.

Question 40

What are the key differences in communication style between Web Services and RESTful services?

Answer 40

Web Services: Message-oriented, using SOAP envelopes. RESTful: Resource-oriented, using HTTP methods.

Question 41

What are the key differences in adoption and use cases between Web Services and RESTful services?

Answer 41

Web Services: Used in enterprise applications requiring security and transactions. RESTful: Used in modern web and mobile applications for simplicity and performance.