Intro to Intro to Software Engineering

Transcription

1 Intro to Intro to Software Engineering John Jannotti CSCI032 (cs032) Jan 28, 2010 John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

2 Introductions Me John Jannotti JJ HTAs Alex Unger Ben Herila TAs Jacob Frank Kevin Doo Osmar Olivo Nathan Partlan Paul Sastrasinh Pete White Rutledge Chin Feman Sam Boger Sandy Ryza Waler Blaurock John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

3 Welcome to CSCI0320 Software Development is... Satisfying Challenging Easy Fun Rewarding Lucrative American or Unpleasant Frustrating Difficult Painful A Waste of Time A Dead End Job Outsourced John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

4 Software Development Software Development Programming Programming is only a small part Other aspects Determining what to build (Reqs and Specs) Determining how to built it (Design) Debugging and testing Maintaining the program Hopefully, software lifetime is mostly maintenance. John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

5 CSCI0320 Covers two types of programming Applications programming Systems programming These have different skill sets Generally different languages & libraries These have different concerns User interaction vs. performance You probably need both If you will program for a living Directly or indirectly John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

6 Programming Languages The language itself is not terribly important Should be able to pick up new ones on your own We ll teach underlying concepts Which are language independent But, how you use the language is important Varies some from one language to another We ll teach this, for Java, C, C++ Most of the course will use Java With techniques that apply to all languages For systems issues we use C and C++ C is standard for low-level programming. C++ is a safe and convenient C, but is big. Large systems often involve multiple languages. John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

7 Choosing the Right Language What language to use is part of design Need good reasons for any language Need to justify choice of language Why Java Easy to teach CSCI0320 concepts Cuts development and debugging time Extensive libraries available Why C/C++ Closer to the machine Performance More flexible Existing libraries Others Scripting languages (python, javascript) Functional languages (lisps, erlang) You will select the right language for your final project. John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

8 What Will Be Taught Skills Advanced Java, C/C++, XML, Multithreading, Sockets, Testing, Debugging, HTML, Web Programming, Libraries, Databases Concepts Design (OO, UI, System, Architecture) Extreme Programming; Team Development; Software Engineering; Systems Development Goals Write 100,000 LoC program Use your skills in other courses, workplace, future projects Start your own business, contribute to FOSS John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

9 Specific Topics Advanced Programming Java features for large-scale development Threads, sockets, and files User interface design and coding Databases Object-oriented design From classes to packages to systems Systems programming Using C and C libraries Abstraction in C C++ as a safe and convenient C Some advanced C++ techniques John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

10 More Topics Tools git, junit, ant, make, gdb,... An alphabet soup of languages, protocols XML, HTML, SQL, HTTP, CSS... Software Engineering Testing Extreme (agile) programming Team software development The software life cycle John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

11 Resources The Elements of Java Style Required Read it. Learn it. Live it. Updates/changes for this course available on-line On-line References JavaDoc, tool documentation, man pages, help files... Will be available on the web site John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

12 Assignments Solar/Galaxy Java refresher; emphasis on testing and design Available online now Real Java programming; XML; OO design; simulation; debugging Galaxy will improve Solar for larger simulations Image based search An arc of three assignments. Will integrate Java and C++. Swing, Web access; Image libraries; C/C++; threads; sockets John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

13 Final Project Project of your choice You own it, you live it Hopefully wont stop at the end of the course Despite my best efforts, you will learn the most from this Team project (4 person teams) Concepts Pull together all your skills Software engineering, project management; software design Handout on-line now Project ideas due in 8 days Team selection due in 15, we encourage heterogeneous teams John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

14 Meetings Lectures (Smith-Buonano 106) Emphasis on design, we ll walk through many case studies. Tue/Thu 2:30pm-3:50pm Weekly Labs Hands-on training you ll need for assignments. Done on your own. Required (20% of grade) Lab times available Tue, Wed, Thu. Communication via the web-site Google calendar and group are linked. Most handouts will not be handed to you. You are responsible for everything there John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

15 Deadlines and Lateness This course will be intense There is no slack in the schedule. Start assignments when they come out. Late policy Early Date: +5% On Time: Full credit Late Date: -15% One late date turnin will be forgiven. No credit at all after the late date. Every assignment must be turned in (and working ) John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

16 Lectures Much of the course is learn-by-doing However Doing is better if it s done right Lectures teach the concepts Will make the programming/design easier Lectures provide the context, examples Historic and future: the why War stories Not everything you will need is in assignments CSCI0320 is a prerequisite for advanced courses Your future classes at Brown expect you to know this material. John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

17 QUESTIONS? About the course itself About the course mechanics Remember to go through the first day checklist John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

18 The Software Crisis Software engineering is a response to what is called the software crisis Why is there a software crisis? Does any of the software you use have problems? John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

19 The Software Crisis Software engineering is a response to what is called the software crisis Why is there a software crisis? Does any of the software you use have problems? Does any of the software you use not have problems? John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

20 Software Problems Problems Always Late Exceeds cost Doesn t satisfy specifications Not maintainable Not understandable or modifiable Unreliable Lacks desired efficiency Not portable Not secure Software engineering is a response to these problems John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

21 Software Engineering Building software that works We know how to build other things Engineering is the discipline that teaches us the methodologies that work for building complex objects Apply engineering techniques to software Knowing what methodologies work Understanding why and how John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

22 Software Engineering Knowledge Fundamentals (theory) Applied sciences (practice) Empirical knowledge (applications) Skills Inventiveness Good judgment and foresight Communication skills Objectivity Methodologies Managing people Organizing software development John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

23 Design as Constraints Design involves finding a solution that satisfies a set of constraints Users needs and wants Target platform or environment Financial or temporal resources Programmer s abilities Competing products Government regulations Set of constraints is essentially infinite Find a practical subset Set priorities and ignore irrelevant ones Find solutions that optimize the remainder John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

24 Software Is Different Set of constraints is continually changing In significant and meaningful ways In unknown and unknowable ways Priorities are changing People expect software to adapt More so than anything else Software often fails to meet expectations Must be built anyway So how do we go about building software This is what software engineering is about John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

25 Requirements Analysis First step in building a system Define the problem from the user s view Determine outlines of best solution Determine what is required & optional Determine limitations on resources Determine acceptance criteria All from the user s point of view Techniques User studies; interviews; surveys Keep the user part of the team First step for you final project You must understand what the user wants before you decide what to build! John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

26 Specifications Analysis Programmer s requirements Detail the problem: what the program does Define the inputs and outputs Define interfaces to existing systems Give a precise statement of what will be done Describe how this meets requirements Develop testing and acceptance plan What, not how Techniques Stories & scenarios; Design diagrams, UML; User manual You have to know what you are going to build before you can design it! John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

27 Software Design What is involved Define system architecture Specify packages, classes and methods Develop data structures and algorithms Problem analysis Define the solution down to a level where it can be easily implemented Key principles Risk Avoidance Simplicity Abstraction John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

28 Software Design Top-Level Design Components and interfaces Define the boundaries between components Components allocated to individuals or groups All communications through interfaces Detailed design Class implementations Helper classes, methods,... Techniques UML; interface code; XP: design as you go (and refactor) Prototyping: try things out as part of design John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

29 Coding AKA Programming Easiest part of the process (If the design is done right) Techniques Emphasis on programming style Emphasis on defensive programming Write tests with (before?) implementations John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

30 Testing Types of Testing Module or class testing unit tests Integration testing putting classes together Systems testing the whole shebang Acceptance testing by user A successful test case finds a problem Testing starts before coding Design: design for and with testing XP: write the test cases first Testing should be thorough and continuous John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

31 Maintenance What it involves Fixing bugs; adding features; adapting Most costly and longest (hopefully) part This is what we want to minimize This is the lesson of software engineering Design for Maintenance Flexibility; planning for change Coding for Maintenance Simplicity; abstraction Coding style; defensive programming John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

32 Models of Software Engineering How to put these phases together How to effectively engineer systems John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

33 Waterfall Model 1 Requirements 2 Specifications 3 Design 4 Coding 5 Testing 6 Maintenance John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

34 Feedback Model 1 Requirements 2 Specifications 3 Design 4 Coding 5 Testing 6 Maintenance Each step may return to a previous step. John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

35 Prototyping Model 1 Requirements 2a Prototype 2 Specifications 3 Design 4 Coding 5 Testing 6 Maintenance Build a prototype from initial requirements. John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

36 Agile Programming What s wrong with these approaches It s unclear what the customer wants It s unclear what really needs to be built It s unclear what is difficult/easy to do It s unclear what the best design is a priori Agile programming attempts to address these concerns John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

37 Agile Components Write the test cases first Testing is the important aspect This gets the design correct; ensures system continues to work Work with the end user continually Not just initially User is part of the development team Work in terms of scenarios Implement vertical functionality; driven by user demand Work with short development cycles Each week, implement a set of scenarios Get feedback after each cycle to determine what next Your projects will be interative, especially final project. John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

38 Agile Components Pair programming Program in pairs, one writing, one reading We encourage you to try this on pair/group work We may allow it on some labs. Shared responsibility Everyone on the team is responsible for all the code in the project We may ask anyone in a group about any part of design. Emphasis on simplicity Write the simplest code possible Avoid complexity unless absolutely necessary Encourage refactoring The best design will evolve As you see ways to improve the design, do so incrementally John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1

39 Agile Programming Model 1 Requirements / Scenarios 2 Test Cases 3 Implementation Even more that in the feedback model, focus is on returning, again and again, to previous steps. John Jannotti (cs32) Intro to Intro to Software Engineering Jan 28, / 1