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Software Engineering Lec5 oop-uml-i

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Taymoor Nazmy

This document discusses object-oriented concepts in software development. It describes the four main types of object-oriented paradigms used in the software lifecycle: object-oriented analysis, design, programming, and testing. It then explains some benefits of the object-oriented approach like modularity, reusability, and mapping to real-world entities. Key concepts like inheritance, encapsulation, and polymorphism are defined. The document also provides examples of how classes and objects are represented and compares procedural with object-oriented programming.

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5- Object-Oriented in Software lifecycle
Object-Oriented in Software lifecycle • Types of object oriented paradigms in SLC: – Object-oriented analysis (OOA) – Object-oriented design (OOD) – Object-oriented programming (OOP) – Object-oriented testing (OOT)
Why OOP? • “Software Crisis” in procedural programming: – Too many modules… – Too many functions… An expensive mess!!! – Too many variables… • While OOP approach provides: 1-Greater Reliability – Break complex software projects into small, self- contained, and modular objects 2- Maintainability – Modular objects make locating bugs easier, with less impact on the overall project
Benefits of OOP.. • 3- Inheritance: Elimination of Redundant Code and extend the use of existing classes. • 4- Encapsulation: Helps in building secure programs. • 5- Easy to map objects in problem domain to those objects in the program. • 6- It is easy to partition the work in a project based on objects.
analysis requirements design using class / object diagrams programming (coding / testing / debugging) in Java OOD OOP: background Simula 1967 C ++ Late 1980s Smalltalk 1972 Java 1991 The UML 1996 C# 2000+ Software life cycle OOPOOA
Procedural vs. OOP • Data Structure A • Data Structure B • Data Structure C • Function A1 • Function A2 • Function B • Function C • Class A – Data Structure A – Function A1 – Function A2 • Class B – Data Structure B – Function B • Class C – Data Structure C – Function C
Software Engineering Lec5 oop-uml-i
Examples of Objects Figure 1.9: Examples of objects CAR VDU BOY GIRL TREEBOOK CLOCK TRIANGLE
Class Candidates • External Entities – devices or people • Things in Problem Domain – Reports, displays, signals • Events – completion of some task • Roles – manager, engineer, salesperson • Organizational Units – divisions, groups, teams • Structures – sensors, vehicles, computers
Unified Modeling Language • UML (Unified Modeling Language) is a modeling technique, which is well suited for object-oriented programming  The UML is approved as a standard and has become widely accepted in the IT industry  The UML is a modeling language, not a software development process; it intends to support different object oriented approaches to software production
Object Oriented Paradigm The General Principle “ An object oriented program is structured as a community of interacting agents called objects. Action is initiated in object oriented programming by the transmission of a message to an agent (an object). The message encodes the request for action and is accompanied by additional information (arguments) needed to carry out the request. The receiver is the agent to which the message is sent. If the receiver accepts the message it accepts the responsibility to carry out the indicated action. In response to a message the receiver will perform some method to satisfy the request. “
OO Concepts • Object – encapsulates both data (attributes) and data manipulation functions (called methods, operations, and services) • Class – generalized description (template or pattern) that describes a collection of similar objects • Superclass – a collection of objects • Subclass – an instance of a class
Classes: Objects with the same attributes and behavior Person Objects Vehicle Objects Polygon Objects Abstract Person Class Attributes: Operations: Name, Age, Sex Speak(), Listen(), Walk() Into Abstract Vehicle Class Attributes: Operations: Name, Model, Color Start(), Stop(), Accelerate() Into Abstract Polygon Class Attributes: Operations: Draw(), Erase(), Move() Vertices, Border, Color, FillColorInto Figure 1.12: Objects and classes
Inheritance • New data types (classes) can be defined as extensions to previously defined types. • Parent Class (Super Class) – Child Class (Sub Class) • Subclass inherits properties from the • parent class. Parent Child Inherited capability
Inheritance - Example • Example – Define Person to be a class • A Person has attributes, such as age, height, gender • Assign values to attributes when describing object – Define student to be a subclass of Person • A student has all attributes of Person, plus attributes of his/her own ( student no, course_enrolled) • A student has all attributes of Person, plus attributes of his/her own (student no, course_enrolled) • A student inherits all attributes of Person – Define lecturer to be a subclass of Person • Lecturer has all attributes of Person, plus attributes of his/her own ( staff_id, subjectID1, subjectID2)
Inheritance - Example • Circle Class can be a subclass (inherited from ) of a parent class - Shape Shape Circle Rectangle
Inheritance - Example • Inheritance can also have multiple levels. Shape Circle Rectangle GraphicCircle
What is Polymorphism? • The ability to hide many different implementations behind a single interface Manufacture A Manufacture B Manufacture C
What is Encapsulation • Hide implementation from clients • Clients depend on interface It associates the code and the data it manipulates into a single unit; and keeps them safe from external interference and misuse. Data Functions
What is Abstraction? Counter Queue Item • An example of an item purchasing abstraction • A model that includes most important aspects of a given problem while ignoring less important details
Java’s OO Features OOP Paradigm Encapsulation Multiple Inheritance Genericity Delegation Persistence Polymorphism Single Inheritance Data Abstraction Java
Object = Identity + State + Behavior • Identity – Distinguishes an object from all other objects. • State – Consists of a set of attributes (or fields), which have names, types, and values. • Behavior – Defined by the set of operations (or methods) that may operate on the object. – Each method has a name, a type, and a value, where • The type consists of the return type and the list of parameter types of the method, often called signature. • The value is the implementation of the method often expressed as a sequence of statements, in languages like Java and C++.
objects – oo-program: consists of a set of communicating objects – object: fundamental abstractions to build software systems where do objects come from ? • From the problem statement • Analyze the problem to identify objects – e.g.: program to manage bank accounts • accounts (Account) • customers (Customer) • transactions (Transaction) • “money machines” (ATM) • windows (MainWindow)
objects: notation • representation object-name : Type name steven : Person c1 : Circle
objects: attributes and operations – example: • account (Account) objects: – attributes: number of account (accountnumber) name of owner (owner) date of opening (date opened) balance at opening initial balance) balance today (current balance) operations: on deposit (deposit) on transfer (transfer) on withdrawl (withdrawal) what’s my balance ? (get balance) queries and commands
objects: notation – attributes and operations c1 : Circle 20.6 radius getRadius getCircumference getSurface
myAccount : Account 098-2356784-45 accountnumber deposit withdraw get balance … 3/10/2004 date opened 1345.04 current balance
dirk : Person Dirk Smith name getName getGender itsYourBirthday … m gender 21 age … current account … savings account
dirk : Person Dirk Smith name getName getGender itsYourBirthday … m gender 21 age … current account … savings account :Account 045-5873784-53 accountnumber deposit withdraw get balance … 2/10/2004 date opened 10945.05 current balance :Account 098-2356784-45 accountnumber deposit withdraw get balance … 3/10/2004 date opened 1345.04 current balance
Class Compartments • A class is comprised of three sections • The first section contains the class name • The second section shows the structure (attributes) • The third section shows the behavior (operations) Lecturer Name save() change() delete() empID create()
Class Compartments (cont.) • The second and third sections may be suppressed if they need not be visible on the diagram Lecturer Name save() change() delete() empID create() Lecturer Name empID Lecturer save() change() delete() create() Lecturer Lecturer
Example of specification for Counter • Start listing its responsibilities: – Class: Counter • queries: – currentCount the current value of count, a non- negative integer • commands: – reset set the value of count to 0 – incrementCount increment the value of count by 1
Defining class Counter in Java /** * A simple integer counter. */ public class Counter { } Definitions of features goes here.
Specifying a Method for a query /** * The number of items counted. */ public int currentCount () { } Method implementation goes here. Type of value returned by query. Name of method.
Specifying a Method for a command /** * The number of items counted. */ public void incrementCount () { } Method implementation goes here. Type of value returned by command. Name of method.
End

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Software Engineering Lec5 oop-uml-i

  • 2. Object-Oriented in Software lifecycle • Types of object oriented paradigms in SLC: – Object-oriented analysis (OOA) – Object-oriented design (OOD) – Object-oriented programming (OOP) – Object-oriented testing (OOT)
  • 3. Why OOP? • “Software Crisis” in procedural programming: – Too many modules… – Too many functions… An expensive mess!!! – Too many variables… • While OOP approach provides: 1-Greater Reliability – Break complex software projects into small, self- contained, and modular objects 2- Maintainability – Modular objects make locating bugs easier, with less impact on the overall project
  • 4. Benefits of OOP.. • 3- Inheritance: Elimination of Redundant Code and extend the use of existing classes. • 4- Encapsulation: Helps in building secure programs. • 5- Easy to map objects in problem domain to those objects in the program. • 6- It is easy to partition the work in a project based on objects.
  • 5. analysis requirements design using class / object diagrams programming (coding / testing / debugging) in Java OOD OOP: background Simula 1967 C ++ Late 1980s Smalltalk 1972 Java 1991 The UML 1996 C# 2000+ Software life cycle OOPOOA
  • 6. Procedural vs. OOP • Data Structure A • Data Structure B • Data Structure C • Function A1 • Function A2 • Function B • Function C • Class A – Data Structure A – Function A1 – Function A2 • Class B – Data Structure B – Function B • Class C – Data Structure C – Function C
  • 8. Examples of Objects Figure 1.9: Examples of objects CAR VDU BOY GIRL TREEBOOK CLOCK TRIANGLE
  • 9. Class Candidates • External Entities – devices or people • Things in Problem Domain – Reports, displays, signals • Events – completion of some task • Roles – manager, engineer, salesperson • Organizational Units – divisions, groups, teams • Structures – sensors, vehicles, computers
  • 10. Unified Modeling Language • UML (Unified Modeling Language) is a modeling technique, which is well suited for object-oriented programming  The UML is approved as a standard and has become widely accepted in the IT industry  The UML is a modeling language, not a software development process; it intends to support different object oriented approaches to software production
  • 11. Object Oriented Paradigm The General Principle “ An object oriented program is structured as a community of interacting agents called objects. Action is initiated in object oriented programming by the transmission of a message to an agent (an object). The message encodes the request for action and is accompanied by additional information (arguments) needed to carry out the request. The receiver is the agent to which the message is sent. If the receiver accepts the message it accepts the responsibility to carry out the indicated action. In response to a message the receiver will perform some method to satisfy the request. “
  • 12. OO Concepts • Object – encapsulates both data (attributes) and data manipulation functions (called methods, operations, and services) • Class – generalized description (template or pattern) that describes a collection of similar objects • Superclass – a collection of objects • Subclass – an instance of a class
  • 13. Classes: Objects with the same attributes and behavior Person Objects Vehicle Objects Polygon Objects Abstract Person Class Attributes: Operations: Name, Age, Sex Speak(), Listen(), Walk() Into Abstract Vehicle Class Attributes: Operations: Name, Model, Color Start(), Stop(), Accelerate() Into Abstract Polygon Class Attributes: Operations: Draw(), Erase(), Move() Vertices, Border, Color, FillColorInto Figure 1.12: Objects and classes
  • 14. Inheritance • New data types (classes) can be defined as extensions to previously defined types. • Parent Class (Super Class) – Child Class (Sub Class) • Subclass inherits properties from the • parent class. Parent Child Inherited capability
  • 15. Inheritance - Example • Example – Define Person to be a class • A Person has attributes, such as age, height, gender • Assign values to attributes when describing object – Define student to be a subclass of Person • A student has all attributes of Person, plus attributes of his/her own ( student no, course_enrolled) • A student has all attributes of Person, plus attributes of his/her own (student no, course_enrolled) • A student inherits all attributes of Person – Define lecturer to be a subclass of Person • Lecturer has all attributes of Person, plus attributes of his/her own ( staff_id, subjectID1, subjectID2)
  • 16. Inheritance - Example • Circle Class can be a subclass (inherited from ) of a parent class - Shape Shape Circle Rectangle
  • 17. Inheritance - Example • Inheritance can also have multiple levels. Shape Circle Rectangle GraphicCircle
  • 18. What is Polymorphism? • The ability to hide many different implementations behind a single interface Manufacture A Manufacture B Manufacture C
  • 19. What is Encapsulation • Hide implementation from clients • Clients depend on interface It associates the code and the data it manipulates into a single unit; and keeps them safe from external interference and misuse. Data Functions
  • 20. What is Abstraction? Counter Queue Item • An example of an item purchasing abstraction • A model that includes most important aspects of a given problem while ignoring less important details
  • 21. Java’s OO Features OOP Paradigm Encapsulation Multiple Inheritance Genericity Delegation Persistence Polymorphism Single Inheritance Data Abstraction Java
  • 22. Object = Identity + State + Behavior • Identity – Distinguishes an object from all other objects. • State – Consists of a set of attributes (or fields), which have names, types, and values. • Behavior – Defined by the set of operations (or methods) that may operate on the object. – Each method has a name, a type, and a value, where • The type consists of the return type and the list of parameter types of the method, often called signature. • The value is the implementation of the method often expressed as a sequence of statements, in languages like Java and C++.
  • 23. objects – oo-program: consists of a set of communicating objects – object: fundamental abstractions to build software systems where do objects come from ? • From the problem statement • Analyze the problem to identify objects – e.g.: program to manage bank accounts • accounts (Account) • customers (Customer) • transactions (Transaction) • “money machines” (ATM) • windows (MainWindow)
  • 24. objects: notation • representation object-name : Type name steven : Person c1 : Circle
  • 25. objects: attributes and operations – example: • account (Account) objects: – attributes: number of account (accountnumber) name of owner (owner) date of opening (date opened) balance at opening initial balance) balance today (current balance) operations: on deposit (deposit) on transfer (transfer) on withdrawl (withdrawal) what’s my balance ? (get balance) queries and commands
  • 26. objects: notation – attributes and operations c1 : Circle 20.6 radius getRadius getCircumference getSurface
  • 27. myAccount : Account 098-2356784-45 accountnumber deposit withdraw get balance … 3/10/2004 date opened 1345.04 current balance
  • 28. dirk : Person Dirk Smith name getName getGender itsYourBirthday … m gender 21 age … current account … savings account
  • 29. dirk : Person Dirk Smith name getName getGender itsYourBirthday … m gender 21 age … current account … savings account :Account 045-5873784-53 accountnumber deposit withdraw get balance … 2/10/2004 date opened 10945.05 current balance :Account 098-2356784-45 accountnumber deposit withdraw get balance … 3/10/2004 date opened 1345.04 current balance
  • 30. Class Compartments • A class is comprised of three sections • The first section contains the class name • The second section shows the structure (attributes) • The third section shows the behavior (operations) Lecturer Name save() change() delete() empID create()
  • 31. Class Compartments (cont.) • The second and third sections may be suppressed if they need not be visible on the diagram Lecturer Name save() change() delete() empID create() Lecturer Name empID Lecturer save() change() delete() create() Lecturer Lecturer
  • 32. Example of specification for Counter • Start listing its responsibilities: – Class: Counter • queries: – currentCount the current value of count, a non- negative integer • commands: – reset set the value of count to 0 – incrementCount increment the value of count by 1
  • 33. Defining class Counter in Java /** * A simple integer counter. */ public class Counter { } Definitions of features goes here.
  • 34. Specifying a Method for a query /** * The number of items counted. */ public int currentCount () { } Method implementation goes here. Type of value returned by query. Name of method.
  • 35. Specifying a Method for a command /** * The number of items counted. */ public void incrementCount () { } Method implementation goes here. Type of value returned by command. Name of method.
  • 36. End