SD 05 UML1 - UHgabriel/courses/cosc3351_s08/SD_05_UML1.pdf · Microsoft PowerPoint -...

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Edgar Gabriel

COSC 3351

Software Design

An Introduction to UML (I)

This lecture contains material from:

www.omg.org/docs/omg/01-03-02.ppt

http://wps.prenhall.com/esm_pfleeger_softengtp_2

http://dn.codegear.com/article/31863

http://sunset.usc.edu/classes/cs577a_2000/lectures/05/EC-05.ppt

Edgar Gabriel

Spring 2008

COSC 3351 – Software Design

Edgar Gabriel

• The UML is a graphical language for

– specifying

– visualizing

– constructing

– documenting

the artifacts of software systems

• Added to the list of OMG adopted technologies in November 1997 as UML 1.1

• Define an easy-to-learn but semantically rich visual modeling language

• Include ideas from other modeling languages

• Incorporate industry best practices

• Address contemporary software development issues

– scale, distribution, concurrency, executability, etc.

• Provide flexibility for applying different processes

• Enable model interchange and define repository interfaces

UML


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Edgar Gabriel

OMG UML Evolution

1997

(adopted by OMG)

1998

1999

Q1 2001

2001 Q4

(planned)

Editorial revision

without significant

technical changes.

2002

(planned)

<<document>>

UML 1.1

<<document>>

UML 1.2

<<document>>

UML 1.3

<<document>>

UML 1.4

<<document>>

UML 2.0

Infrastructure

<<document>>

UML 2.0

<<document>>

UML 2.0

Superstructure

<<document>>

UML 2.0 OCL

composition

(whole-part)

relationship

dependency

relationship

From [Kobryn 01a].


Edgar Gabriel

Type of UML diagrams

• There are different types of UML diagram, each with slightly different syntax rules:– use cases.

– class diagrams.

– sequence diagrams.

– package diagrams.

– state diagrams

– activity diagrams

– deployment diagrams.


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Edgar Gabriel

Different UML diagrams

http://wps.prenhall.com/esm_pfleeger_softengtp_2


Edgar Gabriel

UML syntax (I)

• Actors: a UML actor indicates an interface

(point of interaction) with the system.

– Actors may be people, or other systems.

– Actors used to group and name sets of system

interactions.

– An actor is NOT part of the system. An actor is

something external that your system has to deal

with.

• Boxes: boxes are used variously throughout

UML to indicate discrete elements, groupings

and containment. http://sunset.usc.edu/classes/cs577a_2000/lectures/05/EC-05.ppt

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Edgar Gabriel

UML syntax (II)

• Arrows: arrows usually indicate flow, dependency,

association or generalization (depending on the type of

diagram)

• Cardinality: applied to arrows, show relative numerical

relationships between elements in a model: 1 to 1, 1

to many, etc.



Edgar Gabriel

UML syntax (III)

• Constraints: allow notation of arbitrary constraints on

model elements. Used, for example, to constrain the

value of a class attribute (a piece of data).

• Stereotypes: allow to extend the semantics of UML

with English. A stereotype is usually a word or short

phrase that describes what a diagram element does.

That is, we mark an element with a word that will

remind us of a common (stereotypical) role for that

sort of thing. Stereotypes should always be applied

consistently (with the same intended meaning in all

instances).


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Edgar Gabriel

UML diagrams: use cases (I)

• A use case encodes a typical user interaction with the

system. In particular, it:

– captures some user-visible function.

– achieves some concrete goal for the user.

• A complete set of use cases largely defines the

requirements for a system: everything the user can

see, and would like to do.

• The granularity of use cases determines the total

number of use cases for the system. A clear design

depends on showing the right level of detail.

• A use case maps actors to functions. The actors need

not be people.



Edgar Gabriel

UML diagrams: use cases (II)

• Use case diagrams are helpful in three areas.

– determining features (requirements). New use cases

often generate new requirements as the system is

analyzed and the design takes shape.

– communicating with clients. Their notational simplicity

makes use case diagrams a good way for developers to

communicate with clients.

– generating test cases. The collection of scenarios for a

use case may suggest a suite of test cases for those

scenarios.


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Edgar Gabriel

Example: Relationships in a news web site

UML diagrams: use cases (III)



Edgar Gabriel

UML diagrams: use cases (IV)

• The notes between << >> marks are stereotypes:

identifiers added to make the diagram more

informative. Here they differentiate between different

roles (ie, different meanings of an arrow in this

diagram).


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Edgar Gabriel

What is structural modeling?

• Structural model: a view of a system that

emphasizes the structure of the objects, including

their classifiers, relationships, attributes and

operations.



Edgar Gabriel

Construct Description Syntax

class a description of a set of objects that share the same attributes, operations, methods, relationships and semantics.

interface a named set of operations that characterize the behavior of an element.

component a modular, replaceable and significant part of a system that packages implementation and exposes a set of interfaces.

node a run-time physical object that represents a computational resource.

«interface»

Structural Modeling: Core Elements


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Edgar Gabriel

Structural Modeling: Core Elements(cont’d)


constraint¹ a semantic condition or restriction.

{constraint}

¹ An extension mechanism useful for specifying structural elements.



Edgar Gabriel


association a relationship between two or more classifiers that involves connections among their instances.

aggregation A special form of association that specifies a whole-part relationship between the aggregate (whole) and the component part.

composition strong association in which the part can belong to only one whole

generalization a taxonomic relationship between a more general and a more specific element.

Structural Modeling: Core Relationships


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Edgar Gabriel


realization a relationship between a specification and its implementation.

dependency a relationship between two modeling elements, in which a change to one modeling element (the independent element) will affect the other modeling element (the dependent element).

Structural Modeling: Core Relationships (II)


Zero or more0..*

One or more1..*

Zero or one0..1

Specified range2..7

Exactly one1

Cardinality


Edgar Gabriel

• Show the static structure of the model– the entities that exist (e.g., classes, interfaces,

components, nodes)– internal structure– relationship to other entities

• Do not show– temporal information

• Kinds– static structural diagrams

• class diagram• object diagram

– implementation diagrams• component diagram• deployment diagram

Structural Diagram Tour


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Edgar Gabriel

Class diagrams - example



Edgar Gabriel

Class diagrams (II)

• UML class notation is a rectangle divided into three

parts:

– class name,

– attributes, and

– operations.

• Names of abstract classes, such as Payment, are in

italics.

• Relationships between classes are the connecting links.


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Edgar Gabriel

Class diagrams (III)

• Our class diagram has three kinds of relationships.

– Association: a relationship between instances of the two

classes. There is an association between two classes if an

instance of one class must know about the other in order

to perform its work.

– Aggregation: an association in which one class belongs to

a collection. An aggregation has a diamond end pointing

to the part containing the whole.

– Generalization: an inheritance link indicating one class is

a superclass of the other. A generalization has a triangle

pointing to the superclass.



Edgar Gabriel

Class diagrams (IV)

• A navigability arrow on an association shows which direction

the association can be traversed or queried. An OrderDetailcan be queried about its Item, but not the other way

around. The arrow also lets you know who "owns" the

association's implementation; in this case, OrderDetail has

an Item. Associations with no navigability arrows are bi-

directional.

• The multiplicity of an association end is the number of

possible instances of the class associated with a single

instance of the other end. Multiplicities are single numbers

or ranges of numbers. In our example, there can be only one

Customer for each Order, but a Customer can have any

number of Orders.


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Edgar Gabriel

Class Diagrams (V)

• Associations in which an object is part of a whole are

aggregations. Composition is a strong association in

which the part can belong to only one whole -- the part

cannot exist without the whole. Composition is denoted

by a filled diamond at the whole end.

• This diagram shows that a BoxOffice belongs to exactly

one MovieTheater. Destroy the MovieTheater and the

BoxOffice goes away! The collection of Movies is not so

closely bound to the MovieTheater.



Edgar Gabriel

Class information: visibility and scope

• The illustration uses the following UML™ conventions.

• Static members are underlined. Instance members are not.

• The operations follow this form:

<access specifier> <name> ( <parameter list>) : <return type>

• The parameter list shows each parameter type preceded by a

colon.

• Access specifiers appear in front of each member.


SD 05 UML1 - UHgabriel/courses/cosc3351_s08/SD_05_UML1.pdf · Microsoft PowerPoint -...

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