280 likes | 299 Views
E-commerce Project. Erik Zeitler. Lab 2. Will be anounced and scheduled later We will deploy Java Server Pages on a Tomcat server. Form groups. I want the following information from each group: Names, ”personal numbers”, e-mail addresses Contact person (”project leader”)
E N D
E-commerce Project Erik Zeitler
Lab 2 • Will be anounced and scheduled later • We will deploy Java Server Pages on a Tomcat server. Erik Zeitler
Form groups • I want the following information from each group: • Names, ”personal numbers”, e-mail addresses • Contact person (”project leader”) • Deadline for group formation: Friday Feb 1st Erik Zeitler
Project plan • Project plan deadline: Feb 8th • Project plan: • Description of the business case • ”How will you make money?” • A system architecture • ”How will it work?” • Must include • ER diagram • Use cases • Description of user interface • An implementation plan Erik Zeitler
Office hours • I will be available for questions during the following times, • <see posting on web page> Erik Zeitler
Mid term report • Request a time slot from me • E-mail me • During week 10 (Mar 3rd – Mar 7th) • Any time between 10.15 and 17.15 • We will talk about the progress of your project Erik Zeitler
Final presentation • Presentations • Mon, Mar 31st (all day) • Presentation of your project • Demonstration of a working solution Erik Zeitler
Final report • A written report, including • The business case • A description of the system • Deadline • To be announced. • Probably Tue, Apr 1st • We will ask questions Erik Zeitler
Dream up a business case • Think of a service you want to see • Figure out how to do it in a way that doesn’t suck • Do it Erik Zeitler
How to do it? • Think about the use cases • How will the service be used • Cut the work into pieces • User Interface, application code, database • Assign pieces within the project group • Use Test Driven Development • Test each piece (unit tests) • Test all pieces together (integration/regression tests) Erik Zeitler
Rapid prototyping • Make a simple prototype ASAP • See what new ideas it gives you • ”Often, users don’t know what they want until they see it” – Steve Jobs • Show the prototype to other project groups • Give feedback to each other Erik Zeitler
E-commerce and security? • How can you make sure that • The customers won’t fool you • The customers won’t fool each other • Your site won’t be compromised Erik Zeitler
(Test Driven) Software Development Erik Zeitler
Three-tier architecture • User Interface • What should the user see? • Make drawings • Database • What information will you keep? • Do data modelling, using ER diagrams • Business logic • How will you present the data to the users? • For any non-trivial function, do test driven development Erik Zeitler
Data modelling • Keep persistent data in a database • Customer information • Banking information • Inventory • What do you carry, and how much do you have right now? • Past activity • What has the customer bought? • What has the customer looked at? • What information do you want to store? Why? • Make an Entity Relationship diagram • Translate the ER diagram into SQL tables Erik Zeitler
Example of an ER diagram Erik Zeitler
Why ER diagrams? • ”Keep talking about the algorithms, and everyone will stay totally mystified” • ”Show the ER diagram, and everything else will be obvious” Erik Zeitler
Software development is all about Getting Things Done Priorities in software development: • Make it work • Make it beautiful • Make it fast Erik Zeitler
How? • How to make it work? • First write tests, then write code. This is called Test Driven Development. • How to make it beautiful? • Re-factor • How to make it fast? • Don’t worry about performance until performance is a problem. Erik Zeitler
Why? • Because • Debugging sucks • Testing rocks • Because does it • A test is a specification • The capabilities of a program is defined by its tests • If the tests pass we knowthat the program works – for the test cases. • A test is a piece of documentation Erik Zeitler
The rules of TDD are simple • You can't write production code unless there is a broken test. • First write a test, then write the code • When there is a broken test, you change your code to make it pass. • When your code is working, you refactor to eliminate any code smells… Erik Zeitler
What is code smell? • ”Something is fishy about the code” • http://en.wikipedia.org/wiki/Code_smell • Examples: • Large method • A function that is > 1 page • Duplicated method • A method, function, or procedure that is very similar to another. • Contrived Complexity • Forced usage of overly complicated design patterns where simpler design would suffice Erik Zeitler
A good set of tests • covers all code • performs tests of different scales • tests for all cases, including edge cases and errors Erik Zeitler
Different sized tests isolation,speed confidence in whole system Erik Zeitler
Where is the bug? vs. ”Test failed” ”Test failed” Erik Zeitler
Does the entire system work? + vs. + + + Erik Zeitler
Tests for edge cases and errors • No data, null pointers, garbage data • Very important! • Make sure that no component crashes • Then, the entire system is more likely to stay alive. • Write tests for invalid input data, like • empty strings • null pointers • broken input data Generate exceptions in the production code, catch these exceptions in the test code Erik Zeitler
Automated tests • Netbeans has some infrastructure for testing • You did it in Lab 1, ”Java SE Intro”: Right-click the LibClass.java node in the Projects window and choose Tools >Create JUnit Tests (Ctrl-Shift-U). Erik Zeitler