Unified Modeling Language UML Nelson Padua Perez Chau Wen Tseng Department of Computer Science University of Maryland College Park Overview Unified Modeling Language UML Models views Class diagrams Sequence diagrams 1 UML UML Unified Modeling Language Graphic modeling language for describing object oriented software Started in 1994 Combined notations from 3 leading OO methods OMT James Rumbaugh OOSE Ivar Jacobson Booch Grady Booch UML Motivation Software growing larger complex Difficult to analyze Need to describe software design Clearly Concisely Correctly UML equivalent to software blueprint Provides simple yet clear abstraction for software Computer aided software engineering CASE Tools for generating analyzing UML 2 Definitions Model Abstraction describing all or part of system View Depicts selected aspects of a model using set of diagrams Diagram Actual depiction of aspect of model Notation Set of graphical textual rules for representing view Models Views System Model 1 View 1 View 2 View 3 Model 2 3 UML Industry standard Many features Large collection of notations Multiple views Multiple diagrams We focus mainly on Logical view of relationship between classes UML Views Use Case Show external user actor view of system Logical Show how functionality is implemented Component Show organization of code components Deployment Show assignment of code to physical computers 4 Some UML Diagrams Class Describe static structure of the classes in system Sequence Describe dynamic behavior between users and objects Use case Describe functional behavior seen by external user State Describe dynamic behavior of objects as finite state machine Activity Model dynamic behavior of a system as a flowchart UML Conventions Rectangles classes or instances Ovals functions or use cases Types preceded by colon not underlined SimpleWatch Instances underlined names myWatch SimpleWatch Diagrams graphs Nodes entities Arcs relationships between entities 5 Class Diagrams Class Multiplicity Association SimpleWatch 1 1 1 1 1 2 PushButton state push release 2 LCDDisplay blinkIdx blinkSeconds blinkMinutes blinkHours stopBlinking referesh 1 Battery load Time now Attributes Operations Class diagrams represent structure of system Sequence Diagram Object WatchUser SimpleWatch LCDDisplay pressButton1 blinkHours pressButton1 blinkMinutes pressButton2 Time incrementMinutes refresh pressButtons1And2 commitNewTime stopBlinking Activation Message Sequence diagrams represent behavior as interactions 6 Use Case Diagrams Package SimpleWatch Actor ReadTime SetTime WatchUser Use case WatchRepairPerson ChangeBattery Use case diagrams represent functionality of system from external user s point of view State Diagrams Initial state Event button1 2Pressed button2Pressed Increment Hours Blink Hours Transition button1 2Pressed State button1Pressed Blink Minutes button2Pressed Increment Minutes button1Pressed button2Pressed Stop Blinking Blink Seconds Increment Seconds button1 2Pressed Final state 7 UML Sequence Diagrams Represent behavior in terms of interactions During requirements analysis Used to refine use case descriptions During system design Used to refine subsystem interfaces Sequence Diagram Notation Columns Classes Arrows Messages Narrow rectangles Activations 8 Sequence Diagram Example Sequence of events for printer queue UML Class Diagrams Represent the static structure of the system During analysis Used to model problem domain concepts During detailed design Used to model classes 9 Class Diagrams Class contains Name State Behavior Class Diagrams Types may be included Only class name is required 10 Sequence Diagram Observations Represents behavior in terms of interactions Complement the class diagrams which represent structure Useful for finding participating objects UML Class Diagrams Java Code Different representation of same information Name state behavior of class Relationship s between classes Should be able to derive one from the other Motivation UML Java Implement code based on design written in UML Java UML Create UML to document design of existing code 11 Java UML Clock Example Java class Clock name state int seconds int minutes int hours behavior void start void adjustTime void reset Java Code Class Diagram Java UML Printing System Java class Job class Registry PrintQueue findQueue 12 Java UML Printing System Java class PrintQueue List printJobs Printer myPrinter Registry myRegistry void newJob int length Resources getResource Java UML Printing System Java class Printer Resources myResources Job curJob void print boolean busy boolean on 13 UML Java Printing System UML Java class Printer Resources myResources Job curJob void print boolean busy boolean on Summary Overview of UML Focus on class diagrams How they represent structure of software Conversion to from Java Next lecture will examine How UML represents relationships between classes More UML Java conversions 14
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