Chapter 2 UML Overview

1. Chapter 2 UML Overview • Building blocks of the UML • Structure things in the UML • Behavioral things in the UML • Grouping things in the UML • Relationships in the UML • Diagrams in the UML • Extension mechanism of the UML • Simple Example - Hello World

2. Building Blocks of the UML

3. Building Blocks of the UML • The vocabulary of the UML encompasses three kinds of building blocks: • Things: the abstractions that are first-class citizens in a model; • Relationships: relationships tie these things together; • Diagrams: diagrams group interesting collections of things.

4. Things in the UML • There are four kinds of things in the UML: • Structural things: class, interface, collaboration, use case, active class, component, artifact & node • Behavioral things: interaction, state machine, activity • Grouping things: package • Annotational things: note • These things are the basic object-oriented building blocks of the UML.

5. Structural things in the UML

6. Structural things in the UML • the nouns of UML models. • the mostly static parts of a model, either conceptual or physical • Collectively, the structural things are called classifiers • eight kinds: • Logic view: class, interface, collaboration, • Requirement view:use case • Process view: active class • Implementation view: component, artifact, node

7. Objects Professor Smith Professor Mellon Professor Jones Structural things - Class • A class is a description of a set of objects that share the same attributes, operations, relationships, and semantics. • A class is represented using a compartmented rectangle Attributes Operations

8. Class Name Professor name Attributes empID Operations create( ) save( ) delete( ) change( ) Review: Class Compartments • A class is comprised of three sections • The first section contains the class name • The second section shows the structure (attributes) • The third section shows the behavior (operations)

9. a + b = 10 Professor Clark Review: Representing Objects • An object is represented as rectangles with underlined names : Professor ProfessorClark Class Name Only ProfessorClark : Professor Object Name Only Class and Object Name

10. Pyramid Cube Tube <<interface>> Shape Draw Move Scale Rotate Structural things - Interface • An interfaceis a collection of operations that specify a service of a class or component. • Interfaces support “plug-and-play” architectures Realization relationship

11. Pyramid Pyramid Cube Tube Tube Cube <<interface>> Shape Draw Move Scale Rotate Review: Interface Representations Elided/Iconic Representation(“lollipop”) Shape Canonical (Class/Stereotype) Representation

12. Structural things - Collaboration • In the context of a system's architecture, a collaboration allows you to name a conceptual chunk that encompasses both static and dynamic aspects. • A collaboration names a society of classes, interfaces, and other elements that work together to provide some cooperative behavior that's bigger than the sum of all its parts. • You use collaborations to specify the realization of use cases and operations, and to model the architecturally significant mechanisms of your system.

13. Structural things - Collaboration • A collaboration is a society of classes, interfaces, and other elements that work together to provide some cooperative behavior that's bigger than the sum of all its parts. • A collaboration is also the specification of how an element, such as a classifier (including a class, interface,component, node, or use case) or an operation, is realized by a set of classifiers and associations playing specific roles used in a specific way. • Graphically, a collaboration is rendered as an ellipse with dashed lines. Login Login

14. Structural things – Use Case • a use case is a description of set of sequence of actions that a system performs that yields an observable result of value to a particular actor. • A use case is used to structure the behavioral things in a model. • A use case is realized by a collaboration. • Graphically, a use case is rendered as an ellipse with solid lines, usually including only its name. Login Login

15. EventManager suspend() flush() Structural things – Active Class • an active class is a class whose objects own one or more processes or threads and therefore can initiate control activity. • An active class is just like a class except that its objects represent elements whose behavior is concurrent with other elements. • Graphically, an active class is rendered as a class with double lines on the left and right; it usually includes its name, attributes, and operations.

16. Orderform Structural things – Component • A component is a modular physical part of the system design that hides its implementation behind a set of external interfaces. • The implementation of a component can be expressed by wiring together parts and connectors. • Graphically, a component is rendered like a class with a special icon in the upper right corner.

17. Structural things – Artifact • An artifact is a physical and replaceable part of a system that contains physical information ("bits"). • An artifact typically represents the physical packaging of source or run-time information. • Graphically, an artifact is rendered as a rectangle with the keyword «artifact» above the name. <<artifact>> Login.dll

18. <<Node>> Node #1 Structural things – Node • a node is a physical element that exists at run time and represents a computational resource, generally having at least some memory and, often, processing capability. • A set of components may reside on a node and may also migrate from node to node. • Graphically, a node is rendered as a cube, usually including only its name.

19. Behavioral things in the UML

20. Behavioral things in the UML • the verbs of UML models. • the mostly dynamic parts of a model • three primary kinds: • Among a set of objects: interaction • For an object: state machine • The sequence of steps: activity

21. display() Behavioral things - Interaction • an interaction is a behavior that comprises a set of messages exchanged among a set of objects within a particular context to accomplish a specific purpose. • The behavior of a society of objects or of an individual operation may be specified with an interaction. • An interaction involves a number of other elements, including messages, action sequences (the behavior invoked by a message), and links (the connection between objects). • Graphically, a message is rendered as a directed line, almost always including the name of its operation.

22. Collaboration Diagrams Sequence Diagrams What Is an Interaction Diagram? • An interaction diagram shows an interaction, consisting of a set of objects and their relationships, including the messages that may be dispatched among them. • It models the dynamic aspects of a system.

23. Sequence Diagrams What Is a Sequence Diagram? • A sequence diagram is an interaction diagram that emphasizes the time ordering of messages. • The diagram shows • The objects participating in the interaction. • The sequence of messages exchanged.

24. What Is a Communication Diagram? • A communication diagram emphasizes the organization of the objects that participate in an interaction. • The communication diagram shows • The objects participating in the interaction. • Links between the objects. • Messages passed between the objects. Communication Diagrams

25. Interaction Diagram Example - HelloWorldApp2.java public class HelloWorldApp2 { public static void main(String[] args) { Greeting hello = new Greeting(); hello.greet("Hello World"); } } class Greeting { public void greet(String s) { System.out.println(s); } }

26. Behavioral things - State machine • a state machine is a behavior that specifies the sequences of states an object or an interaction goes through during its lifetime in response to events, together with its responses to those events. • The behavior of an individual class or a collaboration of classes may be specified with a state machine. • A state machine involves a number of other elements, including states, transitions, events, and activities. • Graphically, a state is rendered as a rounded rectangle, usually including its name and its substates, if any. waiting

27. Behavioral things - Activity • an activity is a behavior that specifies the sequence of steps a computational process performs • In an activity, the focus is on the flows among steps without regard to which object performs each step. • A step of an activity is called an action. • Graphically, an action is rendered as a rounded rectangle with a name indicating its purpose. States and actions are distinguished by their different contexts. waiting

28. Grouping things in the UML

29. Grouping things in the UML • A package is a general-purpose mechanism for organizing elements into groups. • In all, there is one primary kind of grouping thing, namely, packages. • Packages are the basic grouping things with which you may organize a UML model. There are also variations, such as frameworks, models, and subsystems (kinds of packages)

30. PackageA PackageB A(from packageA) B(from packageB) Grouping things - Package • Grouping things are the organizational parts of UML models. • Structural things, behavioral things, and even other grouping things may be placed in a package. • Unlike components (which exist at run time), a package is purely conceptual (meaning that it exists only at development time). • Graphically, a package is rendered as a tabbed folder, usually including only its name and, sometimes, its contents. Dependency relationship

31. One of these is executed: Annotational things - Note • Annotational things are the explanatory parts of UML models. • These are the comments you may apply to describe, illuminate, and remark about any element in a model. • There is one primary kind of annotational thing, called a note. • A note is simply a symbol for rendering constraints and comments attached to an element or a collection of elements. • Graphically, a note is rendered as a rectangle with a dog-eared corner, together with a textual or graphical comment.

32. Relationships in the UML

33. Window + open() : void + close() : void + handleEvent(e: Event) : void <<Interface>> AbstractWindow Event + open() : void + close() : void ConsoleWindow DialogBox Control Relationships in the UML • There are four kinds of relationships in the UML: • Association • Dependency • Generalization • Realization

34. <<entity>> <<entity>> <<entity>> Student Schedule Course Professor University Association Name Role Names Works for Employee Employer Association What Is an Association? • The semantic relationship between two or more classes that specifies connections among their instances • A structural relationship, specifying that objects of one thing are connected to objects of another

35. class CatalogueEntry { private string name; private int number; private double cost; publicdouble getCost () { return cost; } } class Part {privateCatalogueEntry entry; public double cost () {return entry.getCost();}} CatalogueEntry screw= new CatalogueEntry (“screw”, 28834, 0.02);Partscrew1 = new Part(screw) ; screw1.cost(); What Is an Association? – A example

36. : CatalogueEntry : CatalogueEntry name = “screw” name = “screw” number = 28834 number = 28834 cost = 0.02 cost = 0.02 Describes Describes : Part : Part Fig. Links between objects getCost() cost() Client : Part Fig. Finding the cost of a Part What Is an Association? – A example • An association is a structual relationship that desribes a set of links. • a link being a connection among objects. • A link specifies a path along which one object can dispatch a message to another (or the same)object.

37. CatalogueEntry Part - name - number + getCost() - cost 1 * + cost() Fig. Example of an association What Is an Association? – A example • In general, a link is an instance of an association.

38. ‘ Schedule.cls Public theStudent as Student Schedule ‘ Student.cls Public theSchedule as Schedule Student Example : Associations mapping to VB 1 1

39. job n n n n Person Company -employee -employer AssociationName Role Names Adornments that apply to associations. • An association name: to describe the nature of the relationship. • When a class participates in an association, it has a specific role that it plays in that relationship. A role is just the face the class at the near end of the association presents to the class at the other end of the association.

40. 1 Multiplicity * 0..* 1..* 1 0..* 0..1 2..4 2, 4..6 University Professor Navigation Adornments that apply to associations. • The multiplicity of an association's role: to state how many objects may be connected across an instance of an association. • Navigation: Given a plain, unadorned association between two classes, it's possible to navigate from objects of one kind to objects of the other kind. • Unspecified • Exactly one • Zero or more (many, unlimited) • One or more • Zero or one • Specified range • Multiple, disjoint ranges

41. Student Schedule Association - Aggregation • A special form of association that models a whole-part relationship between an aggregate (the whole) and its parts Whole Part Aggregation

42. Student Schedule Association - Composition • A form of aggregation with strong ownership and coincident lifetimes • The parts cannot survive the whole/aggregate Part Whole Composition

43. 1..* * -employer -employee Company Person Job -salary + getSalary() Association - Association Class • In an association between two classes, the association itself might have properties. • A class “attached” to an association • Contains properties of a relationship • One instance per link

44. 1..* * -employer -employee Company Person Company Person Job Job 1 1..* * 1 -salary -salary + getSalary() + getSalary() Association - Association Class Design Decisions

45. prerequisites 0..* Course Association - Recursive association

46. 0..1 0..1 has School Department 1 1 1..n 1..n 1..n 1..n 1..n 1..n assignedTo member -chairperson 1..n n n 1..n 0..1 attends teaches Student Course Instructor n n 1..n 1..n n n Association - Example

47. Relationships: Dependency • A relationship between two model elements where a change in one may cause a change in the other • Non-structural, “using” relationship Client Supplier Component Class Supplier Client Package Dependency relationship ClientPackage SupplierPackage Dependency relationship

48. Course Professor Dependency – Example class Professor { public void teach(Course c) { ……..} …………….. } class Professor { public void teach() { Course c = new Course(); ……..} …………….. }

49. HelloWorld paint() Example: HelloWorld.java importjava.applet.Applet; importjava.awt.Graphics; publicclassHelloWorldextendsApplet { public void paint(Graphics g) { g.drawString("Hello World!", 50, 25); } } Applet Dependency relationship Graphics

50. Employee Engineer Manager Relationships: Generalization • A relationship among classes where one class shares the structure and/or behavior of one or more classes • Defines a hierarchy of abstractions in which a subclass inherits from one or more superclasses • Single inheritance • Multiple inheritance • an “is-a-kind of” relationship Generalization relationship