1 / 15

Class and Object Diagrams

Class and Object Diagrams. Class diagram – basic syntax. Association name. Class name. Class name. Attributes. Attributes. Methods. Component. aggregation. Aggregate. Class name. specialization. Class name. This is a subclass. Attributes. Methods. comments.

sylvia
Download Presentation

Class and Object Diagrams

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. Class and Object Diagrams

  2. Class diagram – basic syntax Association name Class name Class name Attributes Attributes Methods Component aggregation Aggregate Class name specialization Class name This is a subclass Attributes Methods comments C-S 546

  3. Class diagram - semantics • a class icon must have a class name. Optionally, it can have attributes and/or methods. • attributes and methods are strings and will not be validated by the modeling tools. • attributes can be specified by their names or by <name, type> pairs. • methods can be specified by their names or partial signature or complete signature. • additional qualifiers for methods (such as public, private or protected) can also be specified. • UML has specific symbols for these qualifiers C-S 546

  4. Class diagram – semantics (continued) • Comments can be included in any diagram with a stripped rectangle • The dotted line from the comment box is important to indicate which portion of the diagram is explained in the comments • When showing aggregation relationship, the aggregate (the one near the diamond edge) must include an attribute whose type is the component class C-S 546

  5. Details of a class icon Account Initial value - Account number : Integer - Balance : Real - Overdraft : Boolean = true • + GetAccountId () • # UpdateBalance (sign : Sign, amt : Integer) • ~ ReturnBalance () : Real • ChangeOverdraft () • + public • private • # protected • ~ visible within the package C-S 546

  6. An abstract class Polygon {abstract, author = Kasi, last modified = Oct 2002} <<constructor>> + Polygon(List of Vertex vertices) <<query>> #area () : Real C-S 546

  7. Object Diagram act : Account : Account Account number = 1256 Balance = 0 Overdraft = false act : Account Various representations of an account object C-S 546

  8. Object diagram (continued) rect : Rectangle topLeft : Coordinate x = 100.0 y = 110.0 bottomRight : Coordiante x = 570.0 y = 390.0 Composite objects - aggregation C-S 546

  9. Association –syntax Association label Direction of association uses customer Account User 1 n Account number Balance Overdraft Manager 1 cardinality Get accountID () Update balance() Return balance() Role names {xor} uses Unary association Corporate Account n C-S 546

  10. Association - Semantics • every association is expected to be labeled • UML does not require a name for an association • direction of an association, cardinality, role name are all optional • for unary associations, role names must be included • representations of cardinality • 0, 1, * (zero or more), n..m (values in the range between n and m both inclusive) • a constraint may be [optionally] placed between two associations • see the example in the previous slide that asserts an Exclusive OR relationship between the associations C-S 546

  11. Association – Semantics (continued) • When a subclass specializes a superclass, it also inherits all associations between the superclass and other classes • In the current example, the association “uses” between “User” and “Account” is also inherited by “Corporate Account” • The diagram shows this association explicitly but it is not necessary to include it in the diagram C-S 546

  12. Association with qualifiers uses Account User 1 n Account number Balance Overdraft Account number Get accountID () Update balance() Return balance() Qualifier attribute Qualifier Corporate Account C-S 546

  13. Association - Qualifiers • Qualifiers can be attached to a “1-many” association • It is rectangle attached to the “many” end of the association • A qualifier is a collection of variables whose values uniquely identify an instance at the “many” end of the association • In the example, an account number uniquely identifies an account in a collection of accounts • Qualifier is part of the association, and not necessarily be a part of the classes participating in the association C-S 546

  14. Association Class User Account Transaction Job Employee Salary C-S 546

  15. Association Class - semantics • a piece of information that belongs to both classes in an association is put into a separate class called “association class” • association class is a dependent class that depends on the other two classes in the association • cannot exist independently • object of an association class must refer to objects of the other two classes in the association • Example: A “Transaction” object depends on a “User” object and on an “Account” object. C-S 546

More Related