Introduction to UML.ppt

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1、Introduction to UML,Majid Ali KhanSpring 2005,Acknowledgements,Slides material are taken from different sources including: Prashanth Aedunuthula UML presentation, Fall 2004 Lecture slides from Software Engineering course at UC Berkeley (Professor Necula Fall 2004) Lecture slides from a course on web

2、 at: www.sts.tu-harburg.de/ teaching/ws-98.99/OOA+D/3-0-UML.pdf,Overview,What is Modeling? What is UML? A brief history of UML Understanding the basics of UML UML diagrams UML Modeling tools,Modeling,Describing a system at a high level of abstraction A model of the system Used for requirements and s

3、pecificationsIs it necessary to model software systems?,Object Oriented Modeling,What is UML?,UML stands for “Unified Modeling Language”It is a industry-standard graphical language for specifying, visualizing, constructing, and documenting the artifacts of software systemsThe UML uses mostly graphic

4、al notations to express the OO analysis and design of software projects. Simplifies the complex process of software design,Why UML for Modeling,Use graphical notation to communicate more clearly than natural language (imprecise) and code(too detailed).Help acquire an overall view of a system.UML is

5、not dependent on any one language or technology.UML moves us from fragmentation to standardization.,History of UML,Types of UML Diagrams,Use Case DiagramClass DiagramSequence DiagramCollaboration DiagramState DiagramThis is only a subset of diagrams but are most widely used,Use Case Diagram,Used for

6、 describing a set of user scenarios Mainly used for capturing user requirements Work like a contract between end user and software developers,Use Case Diagram (core components)Actors: A role that a user plays with respect to the system,including human users and other systems. e.g.,inanimate physical

7、 objects (e.g. robot); an external system that needs some information from the current system. Use case: A set of scenarios that describing an interaction between a user and a system, including alternatives.,System boundary: rectangle diagram representing the boundary between the actors and the syst

8、em.,Use Case Diagram(core relationship),Association: communication between an actor and a use case; Represented by a solid line. Generalization: relationship between one general use case and a special use case (used for defining special alternatives) Represented by a line with a triangular arrow hea

9、d toward the parent use case.,Use Case Diagram(core relationship),Extend: a dotted line labeled with an arrow toward the base case. The extending use case may add behavior to the base use case. The base class declares “extension points”.,Include: a dotted line labeled beginning at base use case and

10、ending with an arrows pointing to the include use case. The include relationship occurs when a chunk of behavior is similar across more than one use case. Use “include” in stead of copying the description of that behavior. ,Use Case Diagrams,Library System,Borrow,Order Title,Fine Remittance,Client,E

11、mployee,Supervisor,A generalized description of how a system will be used. Provides an overview of the intended functionality of the system,Boundary,Actor,Use Case,Use Case Diagrams(cont.),(TogetherSoft, Inc),Use Case Diagrams(cont.),Pay Bill is a parent use case and Bill Insurance is the child use

12、case. (generalization)Both Make Appointment and Request Medication include Check Patient Record as a subtask.(include) The extension point is written inside the base case Pay bill; the extending class Defer payment adds the behavior of this extension point. (extend),Class diagram,Used for describing

13、 structure and behavior in the use cases Provide a conceptual model of the system in terms of entities and their relationships Used for requirement capture, end-user interaction Detailed class diagrams are used for developers,Class representation,Each class is represented by a rectangle subdivided i

14、nto three compartments Name Attributes Operations Modifiers are used to indicate visibility of attributes and operations. + is used to denote Public visibility (everyone) # is used to denote Protected visibility (friends and derived) - is used to denote Private visibility (no one) By default, attrib

15、utes are hidden and operations are visible.,An example of Class,OO Relationships,There are two kinds of Relationships Generalization (parent-child relationship) Association (student enrolls in course) Associations can be further classified as Aggregation Composition,Subtype2,Supertype,Subtype1,OO Re

16、lationships: Generalization,- Generalization expresses a parent/child relationship among related classes. - Used for abstracting details in several layers,Regular Customer,LoyaltyCustomer,Customer,Example:,Regular Customer,LoyaltyCustomer,Customer,or:,Represent relationship between instances of clas

17、ses Student enrolls in a course Courses have students Courses have exams Etc. Association has two ends Role names (e.g. enrolls) Multiplicity (e.g. One course can have many students) Navigability (unidirectional, bidirectional),OO Relationships: Association,Association: Multiplicity and Roles,Univer

18、sity,Person,1,01,*,*,Multiplicity Symbol Meaning 1 One and only one 01 Zero or one MN From M to N (natural language) * From zero to any positive integer 0* From zero to any positive integer 1* From one to any positive integer,teacher,employer,Role,Role “A given university groups many people; some ac

19、t as students, others as teachers. A given student belongs to a single university; a given teacher may or may not be working for the university at a particular time.”,student,Class Diagram,Order,-dateReceived,-isPrepaid,-number :String,-price : Money,+dispatch(),+close(),Customer,-name,-address,+cre

20、ditRating() : String(),Corporate Customer,-contactName,-creditRating,-creditLimit,+remind(),+billForMonth(Integer),Personal Customer,-creditCard#,OrderLine,-quantity: Integer,-price: Money,-isSatisfied: Boolean,Product,*,1,1,*,Employee,*,if Order.customer.creditRating is,“poor“, then Order.isPrepaid

21、 must,be true ,*,1,Constraint (inside braces,Operations,Attributes,Name,Association,Multiplicity: mandatory,Multiplicity: Many value,Multiplicity: optional,Generalization,from UML Distilled Third Edition,class,01,Association: Model to Implementation,Class Student Course enrolls4; Class Course Studen

22、t have; ,Student,Course,enrolls,has,*,4,OO Relationships: Composition,Class W,Class P1,Class P2,Composition: expresses a relationship among instances of related classes. It is a specific kind of Whole-Part relationship. It expresses a relationship where an instance of the Whole-class has the respons

23、ibility to create and initialize instances of each Part-class. It may also be used to express a relationship where instances of the Part-classes have privileged access or visibility to certain attributes and/or behaviors defined by the Whole-class. Composition should also be used to express relation

24、ship where instances of the Whole-class have exclusive access to and control of instances of the Part-classes.Composition should be used to express a relationship where the behavior of Part instances is undefined without being related to an instance of the Whole. And, conversely, the behavior of the

25、 Whole is ill-defined or incomplete if one or more of the Part instances are undefined.,Whole Class,Part Classes,Example,From Dr.David A. Workman,OO Relationships: Aggregation,Class C,Class E1,Class E2,AGGREGATION,Aggregation: expresses a relationship among instances of related classes. It is a spec

26、ific kind of Container-Containee relationship. It expresses a relationship where an instance of the Container-class has the responsibility to hold and maintain instances of each Containee-class that have been created outside the auspices of the Container-class. Aggregation should be used to express

27、a more informal relationship than composition expresses. That is, it is an appropriate relationship where the Container and its Containees can be manipulated independently. Aggregation is appropriate when Container and Containees have no special access privileges to each other.,Container Class,Conta

28、inee Classes,Bag,Apples,Milk,Example,From Dr.David A. Workman,Aggregation vs. Composition,Composition is really a strong form of aggregation components have only one owner components cannot exist independent of their owner components live or die with their owner e.g. Each car has an engine that can

29、not be shared with other cars.Aggregations may form “part of“ the aggregate, but may not be essential to it. They may also exist independent of the aggregate. e.g. Apples may exist independent of the bag.,ClassReservations,ResponsibilityKeep list of reserved titlesHandle reservation,CollaboratorsCat

30、alogUser session,Good Practice: CRC Card,Benefits: It is easy to describe how classes work by moving cards around; allows to quickly consider alternatives.,(Class Responsibility Collaborator),Sequence Diagram(make a phone call),Caller,Phone,Recipient,Picks up,Dial tone,Dial,Ring notification,Ring,Pi

31、cks up,Hello,Sequence Diagram:Object interaction,Self-Call: A message that an Object sends to itself.Condition: indicates when a message is sent. The message is sent only if the condition is true.,Iteration,Condition,Sequence Diagrams Object Life Spans,Creation Create message Object life starts at t

32、hat point Activation Symbolized by rectangular stripes Place on the lifeline where object is activated. Rectangle also denotes when object is deactivated. Deletion Placing an X on lifeline Objects life ends at that point,Activation bar,Sequence Diagram,Sequence diagrams demonstrate the behavior of o

33、bjects in a use caseby describing the objects and the messages they pass. The horizontal dimension shows the objects participating in the interaction. The vertical arrangement of messages indicates their order. The labels may contain the seq. # to indicate concurrency.,Message,Interaction Diagrams:

34、Collaboration diagrams,User,Catalog,Reservations,start,1: look up,2: title data,3 : not available reserve title,4 : title returned,5 : hold title,6 : borrow title,6: remove reservation,5: title available,Shows the relationship between objects and the order of messages passed between them. between th

35、em. The objects are listed as rectangles and arrows indicate the messages being passed The numbers next to the messages are called sequence numbers. They show the sequence of the messages as they are passed between the objects. convey the same information as sequence diagrams, but focus on object ro

36、les instead of the time sequence.,State Diagrams (Billing Example),State Diagrams show the sequences of states an object goes through during its life cycle in response to stimuli, together with its responses and actions; an abstraction of all possible behaviors.,Unpaid,Start,End,Paid,Invoice created

37、,paying,Invoice destroying,State Diagrams (Traffic light example),Yellow,Red,Green,Traffic Light,State,Transition,Green timer expires,Yellow timer expires,Car trips sensor,Event,Start,UML Modeling Tools,Rational Rose () by IBMTogetherSoft Control Center, Borland (http:/ (free software) (http:/argoum

38、l.tigris.org/ )OpenSource; written in java Others (http:/ ),Reference,1. UML Distilled: A Brief Guide to the Standard Object Modeling Language Martin Fowler, Kendall Scott 2. IBM Rational http:/ Practical UML - A Hands-On Introduction for Developershttp:/ Software Engineering Principles and Practice. Second Edition; Hans van Vliet.5. http:/www-inst.eecs.berkeley.edu/cs169/,