1 / 31

Enterprise & Application Frameworks

Enterprise & Application Frameworks. Dr. M.E. Fayad, Professor Computer Engineering Department – RM# College of Engineering San José State University One Washington Square San José, CA 95192-0180 URL: http://www.cmpe.sjsu.edu/~fayad. Lesson 5: Object-Oriented Concepts-3. 2.

megan
Download Presentation

Enterprise & Application Frameworks

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. Enterprise & Application Frameworks Dr. M.E. Fayad, Professor Computer Engineering Department – RM# College of Engineering San José State University One Washington Square San José, CA 95192-0180 URL: http://www.cmpe.sjsu.edu/~fayad SJSU -- CmpE

  2. Lesson 5: Object-Oriented Concepts-3 2 SJSU -- CmpE M.E. Fayad

  3. Lesson Objectives • Discuss UML Associations • Discuss UML – aggregation • Understand UML- inheritance • Explore use case concepts • Understand How to identify UML Artifacts 3 SJSU -- CmpE M.E. Fayad

  4. An association shows a two-way relationship between objects (instances) of two or more classes and requiring special implementation to ensure integrity. A particular instance of an association is often called a link. Associations between classes are required if the objects need to communicate. Associations are often named, and have role-names for each side of the link. Associations 4 SJSU -- CmpE M.E. Fayad

  5. More on Associations Association Name Car Person Vehicle Registration model year # of doors name age address registeredCar owner Roles Names 5 SJSU -- CmpE M.E. Fayad

  6. Simple example: An association has a name and a numerical specification (multiplicity indication) of how many objects on one side of the association are connected with how many objects on the other side. Associations are called use relationships – even if this may seem somewhat cheeky in the example below More on Associations displays 0..* Window GeomFigure employs 0..* Company Person 6 Employer Employee SJSU -- CmpE M.E. Fayad

  7. Associations are directed (one way), bidirectional, and undirected. UML makes no distinction between bidirectional and undirected associations. More on Associations Multiplicity Stereotype RelationName {Constraints} * Class1 Class2 7 role1 Role2: interface SJSU -- CmpE M.E. Fayad

  8. Recursive association: A class has a relation with itself. It is also possible to model associations that are valid only temporarily “stereotype or temporary” Constraints may be used to restrict the relation under specific aspects. A role name describes how the object is seen by the opposite object in the association. An association can be described in more detail by means of constraints, tagged values, and stereotypes. Stereotypes are noted before or above the relation name, constraints, and tagged values after or below the name. More on Associations 8 SJSU -- CmpE M.E. Fayad

  9. Directed association is a one-way association, in which one side knows the other, but not vice versa. Multiplicity Specification: 1 exactly one 0, 1 zero or one 0..4 between zero and four 3, 7 either three or seven More on Associations 9 SJSU -- CmpE M.E. Fayad

  10. More multiplicity specifications: 0..* greater than or equal to zero (default) * ditto 1..* greater than or equal to one 0..3, 7, 9..* between zero and three, or exactly seven, or greater than or equal to nine. More on Associations 10 SJSU -- CmpE M.E. Fayad

  11. Recursive associations are associations in which one class is involved. More on Associations has Patient Employee name staffNo roomNo office clerk relative * * 1 manager Person leads 11 reports to SJSU -- CmpE M.E. Fayad

  12. An n-ary association is like a common (binary) association, except that more than two association roles involved in it. N-ary Association N-ary association Class1 Class2 Ternary association 12 Class3 SJSU -- CmpE M.E. Fayad

  13. More on n-ary Association Reservation Seat Train 1..* 1 carriageNo seatNo date trainNo 1..* Passenger name title Ternary association 13 SJSU -- CmpE M.E. Fayad

  14. More on Associations • Recursive Associations • N-ary Associations • Attributed Associations (Association Class) • Association Constraints • Qualified Associations • Derived Associations • Directed Associations • Ordered Associations • Realization/Refinements • Dependency 14 SJSU -- CmpE M.E. Fayad

  15. More on Associations • Associations are usually bidirectional • Allows each object involved in the relationship to refer to the object to which it is related. • Bidirectional association means at the relationship has an inverse. • Associations do not have to be bidirectional. 15 SJSU -- CmpE M.E. Fayad

  16. Association Type One-to-One One-to-Many (One-to-Zero-or-More) Many-to-Many Zero or One Man Woman Marriage husband wife Screen Window Windows Nets User Authorization Car Trailer 16 SJSU -- CmpE M.E. Fayad

  17. Association Type Specified the # of instances on the “many” side Specify the possible # of instances using “or” Ternary relationship Square Line Sides Secure Room Person Occupants TraditionalFamily Male Female • father mother • children 17 Child SJSU -- CmpE M.E. Fayad

  18. Association Class Server Client Connection Connection baudRate protocol wireType disconnect rerouteLink • These attributes don’t belong in either the Client or Server class. • They are attributes of the connection itself. 18 • The association class can have behaviors as well as attributes. SJSU -- CmpE M.E. Fayad

  19. Aggregation is a special form of association. Aggregation is used when the relationship is “part/whole” or “contains/is-part-of” Aggregation is transitive and operations on “whole” often cascade down to “parts”. Aggregation & Composite 19 SJSU -- CmpE M.E. Fayad

  20. Aggregation & Composite Computer Server Aggregation “whole” “part” 52 * CPU Disk Drive Client Keyboard Mouse 20 SJSU -- CmpE M.E. Fayad

  21. Special diamond symbol used on “whole” side to indicate aggregation. Aggregation is an anti-symmetric that is, if A is part of B, then B is not part of A. DO NOT confuse aggregation with generalization An essential property of aggregates is that the whole acts as a proxy for its parts. A composition is a strict form of aggregation, in which the parts are existence-dependent on the entirely Aggregation & Composite 21 SJSU -- CmpE M.E. Fayad

  22. Aggregation & Composite Aggregation Part Entirely Composition Existence- DependentPart 22 SJSU -- CmpE M.E. Fayad

  23. Mr. Clinton’s hand is part-of Mr. Clinton & Mr. Clinton is part-of U.S.A. Therefore: Mr. Clinton’s hand is part-of U.S.A. Aggregation Problem 23 SJSU -- CmpE M.E. Fayad

  24. Keypad Cash Register Example * Total Key Subtotal Key Number Keys display display display drawer Drawer Display 24 SJSU -- CmpE M.E. Fayad

  25. Attributes are simply the information associated with the object. The data type used to hold the attributes is often a fundamental type, such as int or char. Sometimes the attribute can be a non-fundamental type, such as String type and Address type. Avoid using attributes which might be better implemented as an association to a new class. Attributes 25 SJSU -- CmpE M.E. Fayad

  26. x More on Attributes • For example: Using Association Using Attributes TV TV Manufacturer String model String serialNum String manName String model String serialNum • product manu- • facturer String name Address address * • Why? Using an association to a Manufacturer class, the name and address of each manufacturer will be stored in one place rather than in each of the TV objects made by that manufacturer. 26 SJSU -- CmpE M.E. Fayad

  27. More on Attributes • If attributes only make sense in some instances of a given class but not in others. It will make sense to split the single class into two classes or more. Employee String name float salary Employee Split into two classes String name float salary long clearanceNum inheritance ClearedEmployee 27 long clearanceNum openVault() • Not all employees have clearances SJSU -- CmpE M.E. Fayad

  28. When a relationship exists between classes such that lower-level classes (called subclasses) share certain attributes and behaviors which can be defined once in a higher-level class (called superclasses). Subclasses inherit properties (attributes and behaviors) of its superclass and then adds its own unique properties and modifies any inherited properties. This is called Generalization or Inheritance. Inheritance 28 SJSU -- CmpE M.E. Fayad

  29. More on Inheritance Window paintWindow size icon bitmaps textWindow contents 29 SJSU -- CmpE M.E. Fayad

  30. Aggregation vs. Inheritance AggregationInheritance Instances of distinct classes Instances of a single class “a-part-of” (APO) “a-kind-of” or “is-a” (AKO) Contains superclass-of Aggregate + parts Superclass + subclass “and” relationship “or” relationship Propagated only if specified Inheritance 30 SJSU -- CmpE M.E. Fayad

  31. What are the other terms for attributes & operations? Define an object and a class in UML What is an association? Give examples Associations are usually bidirectional. Please describe. Describe the basic difference between aggregation and inheritance. What do they have in common? What do you think “multiple inheritance” means? Which type of association is more likely to yield savings in the amount of code required for implementation? why? Define the process of identifying objects, classes, inheritance, associations & aggregation, attributes, and behaviors Define Polymorphism with examples What do we mean by saying “Model/View/Controller”? Discussion Questions 31 SJSU -- CmpE M.E. Fayad

More Related