Lecture 01
- 1. Software Construction Dr. Shaukat Ali shaukat@icp.edu.pk
- 2. Course outline • Module 1: Introduction to software construction • Requirement engineering: structural and behavioral modeling using state machines • 1. Introduction to requirements modeling • 2. Behavioral modeling • 3. Communicating state machines • Module 2: Languages, grammars and analyzers • 1. Introduction to languages and compilers • 2. Lexical analysis (formal languages, regular expressions and accepting automata) • 3. Syntax analysis
- 3. Software Processes •A Software Process is • A set of activities (e.g. requirements, analysis, design, coding, testing) combined and sequenced in a particular fashion to produce software
- 4. Software Development Phases Requirements What needs to be done Analysis How it should be done Design Create a software structure (architecture) around which code will be built Coding Fill in the software structure with code Testing Check that the code does what it is supposed to (functionality, performance, reliability, …) Project Management Devise a plan, manage resources, costs, time, …
- 5. Software Phases Related to this Course Design Create a software structure (architecture) around which code will be built Coding Fill in the software structure with code
- 6. Introduction Definition of Software Construction: Detailed creation of working, meaningful software through a combination of coding, verification, unit testing, integration testing, and debugging Software construction closely tied to • Software design • Software testing Design Construction Testing
- 7. Main Activities • Managing Complexity: Programmed systems are always much more complex than the corresponding design • this involves approaches to coping with that complexity oManaging Change: the environment changes and the platform and components change regularly o this involves developing systems that are resilient to anticipated change oFacilitating Validation and Verification: the final code will be subject to test, review, walkthroughs o the structure of the code is an essential influence on ease of validation oStandards Compliance : Important to ensure the capacity to interwork and sometimes an essential to a product
- 8. Managing Complexity oAvoid complexity: by forcing a redesign to remove the complexity from the system oAutomate complexity: use tools to carry out complex, error-prone, tasks that are well understood, encapsulate complexity in manageable components oLocalize complexity : use structuring and hiding to contain complexity inside manageable boundaries. Conceptual tools like coupling and cohesion are useful in identifying and managing locality.
- 9. Managing Change • Both the Environment changes and the platform and components evolve • (some systems just freeze the system and undertake limited maintenance). • Main management approaches • Attempt to generalize the interface to components so the component is capable of easy adaptation • Experiment to identify variability and likely directions for change in the environment • Exploit locality - attempt to generate designs with low coupling so change in components and environments have limited impact on the overall system
- 10. Facilitating Validation • There are a variety of ways of validating systems • Approaches in the code can be helpful • Manual inspection: comments, structure for reading, documentation • Test: code structure to allow good unit test and sensible interfaces so that integration test and the creation of “stubs” and “drivers” is easy
- 11. Complying with Standards • Standards directly affect construction issues • E.g. programming languages, communication methods, platforms, tools, etc. • External standards are often crucial in determining the saleability of products, e.g.: • XML, CORBA, COM, DCOM, and so on in order to ensure interoperability • Quality standards, e.g., Capability Maturity Model (CMM) or ISO 9001 can be crucial in gaining contracts • Internal standards contribute towards organization or project work practice and knowledge
- 12. Reference Chapter 4 of the SWEBOK on Software Construction