MSc. Software Engineering. Examinations for / Semester 1

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MSc. Software Engineering Cohorts: MSE/16B/PT Examinations for 2016 2017/ Semester 1 MODULE: Service Oriented Architecture MODULE CODE: WAT 5101C Duration: 3 Hours Instructions to Candidates: 1.

1 MSc. Software Engineering Cohorts: MSE/16B/PT Examinations for / Semester 1 MODULE: Service Oriented Architecture MODULE CODE: WAT 5101C Duration: 3 Hours Instructions to Candidates: 1. Answer all questions. 2. Questions may be answered in any order but your answers must show the question number clearly. 3. Always start a new question on a fresh page. 4. Questions do not carry equal marks. 5. Total marks 100 This question paper contains 4 questions and 6 pages. Page 1 of 6

2 QUESTION 1: (20 MARKS) a) Briefly describe the term "architectural style" in software development and explain why SOA is considered as an architectural style. (5 marks) b) Describe how the following characteristics can be achieved with SOA i. Modularity ii. Reusability iii. Interoperability iv. Scalability (8 marks) c) Explain how coarse-grained SOA services reduce complexity for system developers. d) Explain the following statement: SOA services can be realised as Web services, but not all Web services are equal to SOA services. (2 marks) e) Asynchronous communication is not required of an SOA service, but it does increase system scalability. Explain how. (2 marks) Page 2 of 6

QUESTION 2: (20 MARKS) a) Loose Coupling is one characteristic of SOA. In practice, this is achieved with the help of a WSDL (Web Services Description Language). Explain how.

3 QUESTION 2: (20 MARKS) a) Loose Coupling is one characteristic of SOA. In practice, this is achieved with the help of a WSDL (Web Services Description Language). Explain how. b) Briefly describe the three main building blocks of a SOAP message. c) A facade is classified as a type of intermediary service in SOA, explain how it can be implemented using XML Web Services. d) Apart from facade, list and briefly describe the other three types of intermediary in SOA. QUESTION 3: (30 MARKS) a) Refer to the Final State Machine (FSM) diagram below, which represents XML tokenisation, also known as the lexical analyser phase, and answer the questions which follow: Page 3 of 6

4 i. Completely described all the different states in the FSM. (8 marks) ii. Modify the FSM where appropriate to include XML attribute processing. b) XML parsers use different models to represent data. Explain the two models below, using diagrams where appropriate with focus on the XML parsing and access steps. i. DOM ii. SAX (10 marks) c) In terms of performance, explain why DOM requires high CPU processing and intensive memory utilisation as compared to SAX. d) Explain how hardware acceleration can boost XML parsing performance. QUESTION 4: (30 MARKS) REpresentational State Transfer (REST) which is also termed as the ROA style is based on four main design principles: Use of HTTP Methods, Stateless Server sides, Structured URLs and Transfer data in XML or JSON a) Fill in the table below, mentioning the usage pattern and whether they are considered as safe or idempotent type HTTP Methods. Page 4 of 6

5 HTTP Method Usage Pattern in REST Approach Type (Safe/Idempotent) GET POST PUT DELETE b) Explain, using an appropriate example, why the HTTP GET method used in REST should avoid state-changing operations. (5 marks) c) Explain, using an appropriate example, how the HTTP PUT method is used in REST. d) Using a simple example, explain how a stateless RESTful Web Service improves performance by saving bandwidth and minimising server-side application state as opposed to a stateful design. e) What is the role of the HTTP MIME types in REST, and explain how they are used by the Content-Type attribute in and HTTP Header. Page 5 of 6

6 f) Convert the following XML document into its JSON representation <?xml version="1.0" encoding="utf-8"?> <program> <batch> <student id='0001'> <name>john Doe</name> <address>some place</address> </student> </batch> <batch> <student id='0002'> <name>jane Doe</name> <address>another place</address> </student> </batch> </program> g) Using your answer above, briefly explain how JSON is more efficient than XML. ***END OF QUESTION PAPER*** Page 6 of 6

Distributed Systems. Web Services (WS) and Service Oriented Architectures (SOA) László Böszörményi Distributed Systems Web Services - 1

Distributed Systems. Web Services (WS) and Service Oriented Architectures (SOA) László Böszörményi Distributed Systems Web Services - 1 Distributed Systems Web Services (WS) and Service Oriented Architectures (SOA) László Böszörményi Distributed Systems Web Services - 1 Service Oriented Architectures (SOA) A SOA defines, how services are