1 / 8

Software Development Cycle

Software Development Cycle. From Wikipedia: http://en.wikipedia.org/wiki/Systems_development_life-cycle Preliminary Analysis Systems analysis, requirements definition Systems design Development Integration and testing Acceptance, installation, deployment Maintenance.

bdeanda
Télécharger la présentation

Software Development Cycle

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Software Development Cycle • From Wikipedia:http://en.wikipedia.org/wiki/Systems_development_life-cycle • Preliminary Analysis • Systems analysis, requirements definition • Systems design • Development • Integration and testing • Acceptance, installation, deployment • Maintenance

  2. Validation vs. Verification • Validation involves testing: white box vs. black box testing, alpha- and beta-test • Testing may be thorough, but not exhaustive • Verification is (mathematically) proving that the program meets the input/output specifications. • Use formal procedures

  3. Types of Errors • Syntax Errors: Missing ; { }, misspelling, case differences, missing declarations, missing import statement, ... • Run-time Errors: Array boundary violations, null pointer exception, ... • Design Flaw: Misunderstanding of program requirements, program works sometimes, but not always

  4. Debugging Strategies • Strategic printing: System.err.println() • Print out values of parameters when entering method and return values before leaving to isolate the error • Use of debugger:http://drjava.sourceforge.net/docs/user/ch09.html • Setting breakpoints, watches • Allows user to interact as program runs

  5. Polymorphism • An object may be of more than one class, e.g., a Ship is a Thing is an Object (due to inheritance) • A derived class may override methods of the base class • Which method is called? • Especially tricky because variables may be cast to other types from what was declared, e.g., Thing[][] b = new Thing[10][10]; b[0][0] = new Ship(4,"Battleship",'B');

  6. Early vs. Late Binding • Early, or static, binding is when the choice is made at compile time. The type of the variable is used to determine which method is called. For example, b[0][0].shootAt() would call the Thing shootAt() method, not the Ship one. • Late, or dynamic, binding is when the choice is made at run-time. The type of the actual object is used to select the method, so Ship shootAt() is called. • Java uses late binding. • This means that objects must know their types.

  7. Static Methods • Since static methods belong to the class, not to an object, late binding cannot be used for them. • Static methods use early, or static, binding. The type of variable determines the method that is called.

  8. Final Modifier • A class may be declared to be final which means that is cannot be subclassed. • A method may be declared to be final which means that it may not be overidden.

More Related