Software Systems EngineeringSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Classes in UML (1)Slide 18Classes in UML (3)Classes in UML (4)Classes in UML (5)Classes in UML (6) - MetaclassesClasses in UML (7) - MetaclassesClasses in UML (8) - Parameterized ClassesClasses in UML (9) - Parameterized ClassesClasses in UML (9) - Abstract ClassesSlide 27Slide 28Classes in UML (9) - Utility ClassesObjects in UML (1)Objects in UML (2)Slide 32Objects in UML (4)Objects in UML (5)Attributes in UML (1)Attributes in UML (2)Attributes in UML (3)Attributes in UML (4)Operations, Methods in UML (1)Operations, Methods in UML (2)Operations, Methods in UML (3)Operations, Methods in UML (4)Operations, Methods in UML (5)Stereotypes in UML (1)Stereotypes in UML (2)Stereotypes in UML (3)Stereotypes in UML (4)Slide 48Interfaces & Interface Classes in UML (1)Interfaces & Interface Classes in UML (2)Interfaces & Interface Classes in UML (3)Interfaces & Interface Classes in UML (4)Constraints in UML (1)Constraints in UML (2)Constraints’ Examples in UML (3)Constraints’ Examples in UML (4)Constraints’ Examples in UML (5)Constraints’ Examples in UML (6)Constraints’ Examples in UML (7)Constraints’ Examples in UML (8)Constraints’ Examples in UML (9)Tagged Values in UML (1)Tagged Values in UML (2)Tagged Values in UML (3)Packages in UML (1)Packages in UML (2)Packages in UML (3)Packages in UML (4)Packages in UML (5)Packages in UML (6)Notes in UML (1)Notes in UML (2)Cooperation / Design Pattern Notation in UML (1)Cooperation / Design Pattern Notation in UML (2)Discussion QuestionsQuestions for the Next Lecture© M.E. Fayad 2000 -- 2006SJSU -- CmpESoftware Systems EngineeringDr. M.E. Fayad, ProfessorComputer Engineering Department, Room #283I College of EngineeringSan José State UniversityOne Washington SquareSan José, CA 95192-0180 http://www.engr.sjsu.edu/~fayad© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S2 Objects & Classes2Lesson 14:Objects & Classes© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S3 Objects & Classes Lesson ObjectivesObjectives3 Overview of Previous Lecture  Explore Modeling Notation Understand Objects, Attributes, Operations, and Notes in UML Discuss the following:– Different Kind of Classes– Class Diagrams© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S4 Objects & ClassesNotationNotation Again !Modeling Notation4© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S5 Objects & ClassesReal-world systems can be decomposed into discrete entities called objectsObjects represent things, concepts, or abstraction with definable boundaries and behaviorsAn object is specific instance of a class to which it belongsClasses have attributes and behaviorsIndividual objects have their own specific values for each attribute and share the same behaviorsObjects & Classes (1)5© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S6 Objects & ClassesExample Objects Classes AttributesA computer screen Screen Resolution, # of colorsA window Window Size, locationIBM Company Name, location, total revenue Joe Harris Employee Name, department, salaryObjects & Classes (2)6© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S7 Objects & ClassesObjects & Classes (3)Objects with the same attributes, behaviors, and relationships are grouped together into classesA class describes general attributes and behaviors for a group of objectsAn object is a single instance of its class (e.g., IBM is an instance of the Company class)A Class diagram is used to describe the attributes and behaviors of a class7© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S8 Objects & ClassesClasses (1)Classes are the most important building block of any Classes are the most important building block of any object-oriented systemobject-oriented systemA class is a description of a set of objects that share A class is a description of a set of objects that share the same attributes, operations, relationships, and the same attributes, operations, relationships, and semantics.semantics.Graphically, a class is rendered as a rectangleGraphically, a class is rendered as a rectangle8© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S9 Objects & ClassesClasses (2)9RegistrationFormRegistrationManagerCourseStudentCourseOfferingProfessorScheduleAlgorithm© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S10 Objects & ClassesNaming & AttributesNaming & AttributesNamingNaming Classes should be named using the vocabulary of the domainClasses should be named using the vocabulary of the domainNaming standards should be created -- e.g., all classes are Naming standards should be created -- e.g., all classes are singular nouns starting with a capital lettersingular nouns starting with a capital letterAttributesAttributesAn attribute is a named property of a class that describes a An attribute is a named property of a class that describes a range of values that instances of the property may holdrange of values that instances of the property may hold10© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S11 Objects & ClassesAttributes11Each course offeringhas a number, location and timeCourseOfferingnumberlocationtime© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S12 Objects & ClassesOperationsOperationsAn operation is the implementation of a service that An operation is the implementation of a service that can be requested from any object of the class to affect can be requested from any object of the class to affect behaviorbehavior12RegistrationManageraddCourse(Student,Course)© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S13 Objects & ClassesResponsibilityResponsibilityA responsibility is a contract or an obligation of a classA responsibility is a contract or an obligation of a class13RegistrationManagerResponsibility:-- manage the registration process© M.E. Fayad 2000 -- 2006SJSU – CmpE M.E. Fayad L3-5a-S14 Objects & ClassesFinding ClassesWhere to find candidate classes:Where to find candidate classes:o Nouns in descriptions or conversationNouns in descriptions or conversationo Checklists of general/typical object typesChecklists of general/typical object typeso Similar computerized systemsSimilar computerized systemso Technical literature in the problem domainTechnical literature in the problem domain14© M.E. Fayad