תרשים המחלקות ותרשים העצמים

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ניתוח ועיצוב מערכות מידע: שלישיחלק UML-באמצעות שימוש ב

Unified Process (UP)-ומתודולוגיית ה

E1 3 E2

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Outline

UML Introduction

Class Diagram Class

Association

Self association

Aggregation & Composition

Dependency

Object Diagram Association

Class Diagram: Qualifiers

Class Diagram: Association Class

Class Diagram: Inheritance (Generalization) 3

UML Introdcution - Modeling

A model is a simplification of reality.

Through modeling we achieve four aims: 1. Models help us to visualize a system as it is or as we want it to be.

2. Models permit us to specify the structure or behavior of a system.

3. Models give us a template that guides us in constructing a system.

4. Models document the decisions we have made.

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UML Introdcution

Donald Bell, Staff, IBM. 15 Jun 2003: Way back in the late twentieth century -- 1997 to be exact -- the Object

Management Group (OMG) released the Unified Modeling Language (UML).

One of the purposes of UML was to provide the development community with a stable and common design language that could be used to develop and build computer applications.

UML brought forth a unified standard modeling notation that IT professionals had been wanting for years.

Using UML, IT professionals could now read and disseminate system structure and design plans -- just as construction workers have been doing for years with blueprints of buildings.

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UML – Unified Modeling Language

Visualizing, specifying, constructing, and documenting object-oriented systems is exactly the purpose of the UML.

Exactly like architects blueprints.

The constructing part is debatable.

You already know how to speak it (Object-Oriented); here you will learn to read and exercise writing it.

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The Diagrams of UML 2.0

Class diagram (s)

Object diagram (s)

Sequence diagram (i)

State machine (b)

Use Case diagram (f)

Package diagram (s)

These ones – we’ll see…

Interaction diagram (i)

Communication diagram (i)

Timing diagram (i)

Activity diagram (f)

Component diagram (s)

Composite diagram (s)

Deployment diagram (s)

…these ones – we won’t.

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Classification of diagrams:

(s) – structure

(b) – behavior

(f) – functional

(i) – interaction

Class Diagram

Definition:

A class diagram is a graphic presentation of the static view

that shows a collection of declarative (static) model elements, such as classes, types, and their content, and relationships.

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Class Diagram Basic Elements:

Class

Elements

Class Name

Typed Attributes

Typed Methods

Visual Representation

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

Class Diagram Basic Elements:

Association

Elements

Association Name

Roles’ name

Multiplicity

a

a..b

a..*

Visual Presentation

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Association - a structural relationship that specifies that objects of one thing (class) are connected to objects of another.

Aggregation - an association between two classes or components defined as “is part of”.

Composition - a strong form of aggregation.

name

-role -role

multiplicity multiplicity

Association

Class Diagram Basic Elements:

Self Association

Association can be between a class and itself.

Recursive data structures, self-reference…

Examples: Class Inheritance and Polymorphism, University Courses with Pre-Requisites.

How would you model a nodes-and-edges graph?

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Class Diagram Basic Elements:

Composition

Composition has exactly two rules which differ it from ordinary associations: A constituent part can belong

to exactly one assembly.

Once a constituent part has been assigned an assembly, it has a coincident lifetime with the assembly.

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Class Diagram Basic Elements:

Aggregation

Aggregation… … is a “Modeling Placebo” –

does not have any actual semantics.

…would be treated just like association in code generation, model analysis, etc.

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Wrong! Right!

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Class Diagram Basic Elements:

Association – Aggregation and Composition

Dependencies - is a relationship that states that one thing (class) uses the information and services of another thing (class).

Underline is the notation for static operation/attributes.

Some patterns reduce dependencies usage to a minimum.

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Class Diagram Basic Elements:

Dependency

רשימת ערים , שםיש טיוללכל . חברת טיולים מארגנת טיולים מסוגים שונים

מספר ימי , מדינה, העיר שםי "מוגדר ע עיר. ותאריך חזרה תאריך יציאה, לביקור

, מדריך יכול להדריך בערים שונים(. כתובתו שם, ז.ת) המדריךופרטיו של לביקור

. עבור כל טיול מנהלים רשימת מטיילים. אך לכל עיר יכול להיות מדריך אחד בלבד

. לטיול מחירו (מספר,קוד) טלפוניםרשימת , שם, ז.תי "מוגדר ע מטייל

(הסיפור או הדיאגראמה)מה יותר מובן?

-name

-departure

-arrival

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-name

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-name

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1..* 1

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-number

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חברת טיולים - 1דוגמה

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אך לא ) סמינריםלהיות מורכב ממספר יכול קורסכל . באוניברסיטה ניתנים קורסים

. חייב להשתתף לפחות בסמינר אחד סטודנטכל . לסמינר משובצים סטודנטים. (חייב

. סטודנטשל הסמינר הוא עוזר ההוראה

roles ו- associations השתמשו בהם ⇐מאוד חשובים להבנת התרשים והמערכת .

ברירות המחדל שלmultiplicity ציינו במפורש את ה⇐ מבלבלות ובעייתיות-multiplicity.

0..*

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קורסים באוניברסיטה - 2דוגמה

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Object Diagram

It depicts objects and their relationships at a certain point in time, typically a special case of either a class diagram or a communication diagram [Scott W.Ambler].

It shows instances instead of classes.

They are useful for explaining small pieces with complicated relationships, especially recursive relationships. [Randy Miller]

It is closely linked to class diagram. Just as an object is an instance of a class, an object diagram could be viewed as an instance of a class diagram.

It is used for testing and refining class diagram.

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Elements

Object Name

Attributes

Links Name

Type

Association

Aggregation

Composition

Generalizations

Dependencies

Visual Presentation

Why there is no multiplicity?

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-attribute 1 = "value"

-attribute 2="value"

-...........

-attribute n="value"

object name : class:class

object name : class

name

link

-role -role

Object Diagram Basic Elements:

Links and Associations

(2המשך מדוגמא ) 3דוגמה

a) Right OD b) Wrong OD

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•OD תקין/שגוי?

.associations -לגרוע על כמות ה/לא יכולה לעלות links-כמות ה•

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(המשך) 3דוגמה

•OD תקין/שגוי?

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4דוגמה

{NAND}

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sem2 : Seminar

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Class Diagram: Qualifiers

מה מהבאים הכי נכון -במדינה יש כמה ערים ולכולם שמות שונים?

.a

.b

.c

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Class Diagram: Association Class

An association class is an association whose links have identities.

It is possible to define a association class if relationship between classes has additional properties.

Association class constraint: A single instance of the association between any 2 instances of the

associated class (the regular association constraint).

An association class can have attributes.

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Association Class – Definitive Example

A rule of thumb

Association classes are better for many to many relationships.

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/etc/termcap read John Doe

/etc/termcap read-write Mary Brown

/usr/does/.login read-write John Doe

יש לשמור את תיאור . עובדים משובצים לפרויקטים שונים בתפקידים שונים

.התפקיד ומשכורת של עובד פר פרויקט עליו הוא עובד

The constraint comes from the association semantics.

David:Employee

Oren:Employee

p1:Project

p2:Project

-description="manager"

-salary="10..."

DavidP1:Role

-description="tester"

-salary="50..."

OrenP1:Role

-description="tester"

-salary="50..."

OrenP2:Role

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a) Class Diagram b) Object Diagram

עובדים בפרויקט – 5דוגמה

What do the diagrams describe ?

a) b)

c)

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Class Diagram: Inheritance (Generalization)

Inheritance models “is a” and “is like” relationship, enabling you to reuse existing data and code easily.

The subclass inherits from super-class: Attribute

Operation

Relationship

Interface

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Class Diagram: Inheritance (Generalization)

Some patterns:

Create a conceptual subclass of a super-class when:

1. The subclass has additional attributes of interest.

2. The subclass has additional associations of interest.

3. The subclass concept is operated on, handled, reacted to, or manipulated differently than the super-class or other subclasses, in ways that are of interest.

4. The subclass concept represents an animate thing (for example, animal, robot) that behaves differently than the super-class or other subclasses, in ways that are of interest.

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Class Diagram: Inheritance (Generalization)

Create a conceptual super-class in a generalization relationship to subclasses when:

1. The potential conceptual subclasses represent variations of a similar concept.

2. The subclasses will conform to the 100% and Is-a rules.

3. All subclasses have the same attribute which can be factored out and expressed in the super-class.

4. All subclasses have the same association which can be factored out and related to the super-class.

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Representing Abstract Concepts and their Concrete Manifestations

What is a flight?

The plane?

The path?

Both – but in two different contexts?

So let’s represent it!

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