More Related Content
Similar to Review of object orientation
Review of object orientation
- 1. Review of ObjectOrientation
- 2. What is ObjectOrientation? Procedural paradigm: • Software is organized around the notion of procedures • Procedural abstraction • Works as long as the data is simple • Adding data abstractions • Groups together the pieces of data that describe some entity • Helps reduce the system’s complexity. • Such as Records and structures Object oriented paradigm: • Organizing procedural abstractions in the context of data abstractions © Gurbakash Phonsa Object Oriented concept review 2
- 3. Object Oriented paradigm Anapproach to the solution of problems in which all computations are performed in the context of objects. • The objects are instances of classes, which: • are data abstractions • contain procedural abstractions that operation on the objects • A running program can be seen as a collection of objects collaborating to perform a given task © Gurbakash Phonsa Object Oriented concept review 3
- 4. A View ofthe Two paradigms main perform transaction compute fees if checking then xxx if savings then xxx etc. compute interest if checking then xxx if savings then xxx etc. debitcredit Account credit debit SavingsAccount compute interest compute fees CheckingAccount compute interest compute fees © Gurbakash Phonsa Object Oriented concept review 4
- 5. Classes and Objects •Object • A chunk of structured data in a running software system • Has properties • Represent its state • Has behaviour • How it acts and reacts • May simulate the behaviour of an object in the real world © Gurbakash Phonsa Object Oriented concept review 5
- 6. Objects © Gurbakash PhonsaObject Oriented concept review 6 Manit: date of birth: 1990/03/03 position: Teller Transaction 0487: amount: 2200.00 time: 2011/09/01 14:30 MrGarg: date of birth: 1980/01/01 address: 75 Object Dr. Mortgage Account 209865: balance: 198760.00 opened: 2015/08/15 property: 75 Object Dr. Instant Teller 9876: location: Java Valley Cafe Savings Account 0012876: balance: 19076.32 opened: 1997/03/03 Sandeep: date of birth: 1985/02/02 position: Manager address: 99 UML St. address: 150 C++ Rd.
- 7. Classes • A class: •Is a unit of abstraction in an object oriented (OO) program • Represents similar objects • Its instances • Is a kind of software module • Describes its instances’ structure (properties) • Contains methods to implement their behaviour © Gurbakash Phonsa Object Oriented concept review 7
- 8. Naming classes • Usecapital letters • e.g. BankAccount not bankAccount • Use singular nouns • Use the right level of generality • e.g. Municipality, not City • Make sure the name has only one meaning • e.g. ‘bus’ has several meanings © Gurbakash Phonsa Object Oriented concept review 8
- 9. Instance Variables • Variablesdefined inside a class corresponding to data present in each instance i. Attributes • Simple data • e.g. name, dateOfBirth ii. Associations • Relationships to other important classes • e.g. supervisor, coursesTaken © Gurbakash Phonsa Object Oriented concept review 9
- 10. Variables vs. Objects Avariable • Refers to an object • May refer to different objects at different points in time An object can be referred to by several different variables at the same time Type of a variable • Determines what classes of objects it may contain © Gurbakash Phonsa Object Oriented concept review 10
- 11. Class variables • Aclass variable’s value is shared by all instances of a class. • Also called a static variable • If one instance sets the value of a class variable, then all the other instances see the same changed value. • Class variables are useful for: • Default or ‘constant’ values (e.g. PI) • Lookup tables and similar structures Caution: do not over-use class variables © Gurbakash Phonsa Object Oriented concept review 11
- 12. Methods, Operations andPolymorphism Operation • A higher-level procedural abstraction that specifies a type of behaviour • Independent of any code which implements that behaviour • E.g., calculating area (in general) © Gurbakash Phonsa Object Oriented concept review 12
- 13. Methods, Operations andPolymorphism • Method • A procedural abstraction used to implement the behaviour of a class. • Several different classes can have methods with the same name • They implement the same abstract operation in ways suitable to each class • E.g, calculating area in a rectangle is done differently from in a circle © Gurbakash Phonsa Object Oriented concept review 13
- 14. Polymorphism A property ofobject oriented software by which an abstract operation may be performed in different ways in different classes. • Requires that there be multiple methods of the same name • The choice of which one to execute depends on the object that is in a variable • Reduces the need for programmers to code many if-else or switch statements © Gurbakash Phonsa Object Oriented concept review 14
- 15. Organizing Classes intoInheritance Hierarchies Superclasses • Contain features common to a set of subclasses Inheritance hierarchies • Show the relationships among superclasses and subclasses • A triangle shows a generalization Inheritance • The implicit possession by all subclasses of features defined in its superclasses © Gurbakash Phonsa Object Oriented concept review 15 Superclass Subclass
- 16. Example Inheritance Hierarchy Inheritance •The implicit possession by all subclasses of features defined in its superclasses © Gurbakash Phonsa Object Oriented concept review 16 Account MortgageAccountSavingsAccount ChequingAccount
- 17. The Isa Rule Alwayscheck generalizations to ensure they obey the isa rule • “A checking account is an account” • “A village is a municipality” Should ‘Province’ be a subclass of ‘Country’? • No, it violates the isa rule • “A province is a country” is invalid! © Gurbakash Phonsa Object Oriented concept review 17
- 18. A possible inheritancehierarchy of mathematical objects © Gurbakash Phonsa Object Oriented concept review 18 Rectangle Quadrilate ralCircle Ellipse Polygon PlaneLine Shape3DShape2D MatrixShape Point MathematicalObject
- 19. Make Sure allInherited Features Make Sense in Subclasses © Gurbakash Phonsa Object Oriented concept review 19 Account balance opened creditOrOverdraftLimit credit debit calculateInterest MortgageAccount collateralProperty collateralValue setCollateralValue ChequingAccount highestChequeNumber withdrawUsingCheque calculateServiceCharge SavingsAccount
- 20. Inheritance, Polymorphism and Variables © GurbakashPhonsa Object Oriented concept review 20 RegularPolygon numPoints radius changeNumPoints changeScale getArea getPerimeterLength getVertices Rectangle height width setHeight setWidth changeScale getArea getPerimeterLength getVertices getBoundingRect ArbitraryPolygon points addPoint removePoint rotate changeScale getArea getPerimeterLength getVertices SimplePolygon orientation rotate Shape2D rotate translate changeScale getArea getPerimeterLength getCenter getBoundingRect Ellipse getSemiMajorAxis getSemiMinorAxis rotate getArea getPerimeterLength getOrientation getBoundingRect Circle rotate getArea getPerimeterLength getBoundingRect Polygon getVertices getBoundingRect EllipticalShape semiMajorAxis semiMinorAxis changeScale changeScale getRadius getFocus1 getFocus2 orientation getOrientation center
- 21. UML Basics Design Model ProcessModel Deployment Model
- 22. What Is theUML? • The UML is a language for • Visualizing • Specifying • Constructing • Documenting The artifacts of a software-intensive system. • The Unified Modelling Language (UML) is an industry standard for object oriented design notation, supported by the Object Management Group (OMG).
- 23. The UML Isa Language for Visualizing • Communicating conceptual models to others is prone to error unless everyone involved speaks the same language. • There are things about a software system you can’t understand unless you build models. • An explicit model facilitates communication.
- 24. The UML Isa Language for Specifying • The UML builds models that are precise, unambiguous, and complete.
- 25. The UML Isa Language for Constructing • UML models can be directly connected to a variety of programming languages. • Maps to Java, C++, Visual Basic, and so on • Tables in a RDBMS or persistent store in an OODBMS • Permits forward engineering • Permits reverse engineering
- 26. The UML Isa Language for Documenting Use Case Diagram Actor A Use Case 1 Use Case 2 Use Case 3 Actor B Class Diagram GrpFile read( ) open( ) create( ) fillFile( ) rep Repository name : char * = 0 readDoc( ) readFile( ) (from Persistence) FileMgr fetchDoc( ) sortByName( ) DocumentList add( ) delete( ) Document name : int docid : int numField : int get( ) open( ) close( ) read( ) sortFileList( ) create( ) fillDocument( ) fList 1 FileList add( ) delete( ) 1 File read( ) read() fill the code.. Sequence Diagram user mainWnd fileMgr : FileMgr repositorydocument : Document gFile 1: Doc view request ( ) 2: fetchDoc( ) 3: create ( ) 4: create ( ) 5: readDoc ( ) 6: fillDocument ( ) 7: readFile ( ) 8: fillFile ( ) 9: sortByName ( ) ƯÁ¤¹®¼¿¡ ´ëÇÑ º¸±â¸¦ »ç¿ëÀÚ°¡ ¿äûÇÑ´Ù. ÈÀÏ°ü¸®ÀÚ´Â Àоî¿Â ¹®¼ÀÇ Á¤º¸¸¦ ÇØ´ç ¹®¼ °´Ã¼¿¡ ¼³Á¤À» ¿äûÇÑ´Ù. È¸é °´Ã¼´Â ÀоîµéÀÎ °´Ã¼µé¿¡ ´ëÇØ À̸§º°·Î Á¤·ÄÀ» ½ÃÄÑ È¸é¿¡ º¸¿©ÁØ´Ù. The UML addresses documentation of: System architecture Requirements System Testing Project planning and Release management Deployment Diagram Window95 ¹®¼°ü¸® Ŭ¶óÀ̾ðÆ®.EXE Windows NT ¹®¼°ü¸® ¿£Áø.EXE Windows NT Windows95 Solaris ÀÀ¿ë¼¹ö.EXE Alpha UNIX IBM Mainframe µ¥ÀÌŸº£À̽º¼¹ö Windows95 ¹®¼°ü¸® ¾ÖÇø´ ºÐ»ê ȯ°æÀÇ Çϵå¿þ¾î¹× ³×Æ®¿÷À¸·ÎÀÇ Á¤º¸ ½Ã½ºÅÛ ¿¬°á ¸ðµ¨ - À©µµ¿ì 95 : Ŭ¶óÀ̾ðÆ® - À©µµ¿ì NT: ÀÀ¿ë¼¹ö - À¯´Ð½º ¸Ó½Å: ÀÀ¿ë ¼¹ö ¹× µ¥ÀÌŸ ¼¹ö, Åë½Å ¼¹ö - IBM ¸ÞÀÎÇÁ·¹ÀÓ: µ¥ÀÌŸ ¼¹ö, Åë½Å ¼¹ö
- 27. History of theUML UML 1.0 (Jan. ‘97) UML 1.1 (Sept. ‘97) UML 1.5 (March, ‘03) UML 2.0 (2004) Other Methods Booch ‘91 OMT - 1OOSE Booch ’93 OMT - 2 Public FeedbackUnified Method 0.8 (OOPSLA ’95) UML 0.9 (June ‘96) UML 0.91 (Oct. ‘96) and
- 28. Diagrams • Diagrams graphicallydepict a view of a part of your model. • Different diagrams represent different views of the system that you are developing. • A model element will appear on one or more diagrams.
- 29. UML Diagrams inSoftware Architecture Behavioral Diagrams Structural DiagramsActivity Diagrams Sequence Diagrams Communication Diagrams State Machine Diagrams Deployment Diagrams Component Diagrams Composite Structure Diagrams Class Diagrams Use-Case Diagrams Model
- 30. Key Diagrams inUML Requirements System Structure System Behaviour Use Case Diagrams Interaction Diagrams Activity Diagrams State Charts Class Diagrams Collaboration Diagrams
- 31. Different diagrams ofsystem for different people Process View Deployment View Logical View Use-Case View Implementation View End-user Functionality Programmers Software management Performance, scalability, throughput System integrators System topology, delivery, installation, communication System engineering Analysts/Designers Structure
- 32. UML Building Blocks UMLBuilding Blocks © Gurbakash Phonsa Object Oriented concept review 32