IT1204 – Software Engineering L6
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The document discusses the software engineering process, focusing on the waterfall model and various design strategies such as functional and object-oriented design. It outlines essential design principles, including the Single Responsibility Principle and Dependency Inversion Principle, which improve code maintainability. The document also mentions the importance of testing, including both manual and automated approaches, to identify errors and ensure software quality.
IT1204 – Software Engineering L6
- 1. Software Engineering L6 Sameera Gunathilaka Lead Software Engineer ERP Technical Consultant IT1204 – Software Engineering Institute of Technology, University of Moratuwa 1
- 2. SDLC – Waterfall Model IT1204 – Software Engineering Institute of Technology, University of Moratuwa 2
- 3. IT1204 – Software Engineering Institute of Technology, University of Moratuwa 3
- 4. IT1204 – Software Engineering Institute of Technology, University of Moratuwa 4 The idea is actually transformed in to a real working system Problem Domain Solution Domain
- 5. Architectural design Abstract specificatio n Interface design Component design Data structure design Algorithm design Sy stem architecture Software specification Interface specification Component specification Data structure specification Algorithm specification Requirements specification Design activities Design products IT1204 – Software Engineering Institute of Technology, University of Moratuwa 5
- 6. Design Activities • Architectural design: Identify sub-systems. ( Inventory/ HR/ Finance) • Abstract specification: Specify sub-systems. (Inventory > Part Management, Finished good, Raw material) • Interface design: Describe sub-system interfaces( Raw materials > Receive Raw material, Supplier Order, Show on hand quantity) • Component design: Decompose sub-systems into components(material, order, supplier) • Data structure design: Design data structures to hold problem data(Material > Name, price, on hand quantity, category) • Algorithm design: Design algorithms for problem functions. ( Calculate_safety_stock) IT1204 – Software Engineering Institute of Technology, University of Moratuwa 6
- 7. Design Strategy IT1204 – Software Engineering Institute of Technology, University of Moratuwa 7 Function Oriented Design – Procedural approach Object Oriented Design – OO approach
- 8. SOLID Design Principles - OOD Make software designs more understandable, flexible and maintainable. IT1204 – Software Engineering Institute of Technology, University of Moratuwa 8
- 9. S - Single responsibility principle IT1204 – Software Engineering Institute of Technology, University of Moratuwa
- 10. S - Single responsibility principle • Testing – A class with one responsibility will have far fewer test cases • Lower coupling – Less functionality in a single class will have fewer dependencies • Organization – Smaller, well-organized classes are easier to search than monolithic ones IT1204 – Software Engineering Institute of Technology, University of Moratuwa 10 Person Add Person Add Address Address Add Address
- 11. O- Open Close Principle IT1204 – Software Engineering Institute of Technology, University of Moratuwa 11 Open for Extension, Closed for Modification Stop ourselves from modifying existing code and causing potential new bugs
- 12. IT1204 – Software Engineering Institute of Technology, University of Moratuwa 12
- 13. L - Liskov Substitution principle IT1204 – Software Engineering Institute of Technology, University of Moratuwa 13 Child class should be perfectly substitutable for their parent class If class C is derived from P then C should be substitutable for P. Using base class then derived class should be able to extend their base class without changing their original implementation
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- 15. I - Interface Segregation Principle You shouldn't be forced to implement an interface when your object doesn't share that purpose
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- 18. D- Dependency Inversion Principle IT1204 – Software Engineering Institute of Technology, University of Moratuwa 18 High-level modules should not depend on low-level modules. Both should depend on abstractions Abstractions should not depend on details. Details (concrete implementations) should depend on abstractions
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- 21. Framework • A software framework is a software model for development of software applications • framework is made up of one or many components • components generally include programs and code libraries IT1204 – Software Engineering Institute of Technology, University of Moratuwa 21
- 22. Code Compilation Translating formal language to machine instructions IT1204 – Software Engineering Institute of Technology, University of Moratuwa 22
- 23. Runtime vs Compile time IT1204 – Software Engineering Institute of Technology, University of Moratuwa 23
- 24. Errors IT1204 – Software Engineering Institute of Technology, University of Moratuwa 24 Compile time Runtime Syntax errors Exceptions Typechecking errors Dereferencing a null pointer Compiler crashes (Rarely) Running out of memory Division by zero
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- 27. 3 – tire architechture IT1204 – Software Engineering Institute of Technology, University of Moratuwa 27
- 28. Testing Testing is executing a system in order to identify any gaps, errors, or missing requirements in contrary to the actual requirements. IT1204 – Software Engineering Institute of Technology, University of Moratuwa 28
- 29. Testing IT1204 – Software Engineering Institute of Technology, University of Moratuwa 29 MANUAL TESTING AUTOMATION TESTING (TOOLS: SELENIUM, LOADRUNNER)
- 30. Thank you IT1204 – Software Engineering Institute of Technology, University of Moratuwa 30
Editor's Notes
- #4: Requirements engineering help software engineers to better understand the problem they will work to solve. It encompasses the set of tasks that lead to an understanding of what the business impact of the software will be, what the customer wants and how end-users will interact with the software.
- #5: Transformation phase The idea is actually transformed in to a real working system
- #24: CIL – common interface language