object-oriented programming introduction to uml class...

ObjectObject--Oriented Programming Oriented Programming Introduction toIntroduction to

UML Class DiagramsUML Class Diagrams

CSIE Department, NTUT

Woei-Kae Chen

UML: UML: Unified Modeling LanguageUnified Modeling LanguageSuccessor to OOA&D methods– late 1980s and early 1990s

Unifies– Jacobson & OMT (Booch & Rumbaugh)

Graphical notation used to express designs– Use cases– Class diagrams– Interaction diagrams

Sequence diagramsCollaboration diagrams

– Package diagrams– State diagrams– Activity diagrams– Deployment diagrams

GoF Book

UML class diagramsUML class diagramsThree perspectives– Conceptual

represents of the domain under studyrelate to the class that implement them, but often no direct mapping

– Specificationlooking at types rather than classesa type represents an interface that may have different implementations

– Implementationlooking at classes for our OOP class

UML: a classUML: a class

function1()function2()

variable1variable2

class_name+ public# protected- private

AbstractConcrete

•data type•parameter

Example: OBSort1Example: OBSort1.cpp.cpp

+getInput()+printOutput()+Sort()+cleanUp()+getSize()

-a-size

IntArray

Example: OBSort1Example: OBSort1.cpp.cpp

+getInput()+printOutput()+Sort()+cleanUp()+getSize()

-a-size

IntArray

Context(main)

Let’s assume main() is a class

relationship

UML: class relationshipUML: class relationshipAssociation (knows a)Dependency (uses a)Composition (has a)Aggregation (has a)

Inheritance (is a)

Class template XY

X Y

X Y

X Y

X Y

Y

X

(parameterizedclass)

““Uses aUses a”” ““Knows aKnows a”” relationshiprelationship

“Uses a”– Dependency– One object issues a function

call to a member function of another object

“Knows a”– Association– One object is aware of

another; it contains a pointer or reference to another object

X Y

X Y

““Is aIs a”” ““Has aHas a”” relationshiprelationship“Is a” relationships– Inheritance– a class is derived from

another class

“Has a” relationships– Composition or Aggregation– a class contains other

classes as members

X

Y

X Y

X Y

Aggregation Aggregation CompositionComposition

Both are “Has a” or “part-of” relationshipComposition– a stronger variety of aggregation– the part object may belong to only one whole– expected to live and die with the whole

delete whole delete partAggregation– cascading delete is often– an aggregated instance can be shared

X Y X Y

Example: Example: ““has ahas a”” relationshiprelationship

colorisFilled

Style

Polygon

13..*

Point

*

1

{ordered}

radiusCircle

1

1

*1

Multiplicity

a Point may appear in only one Polygon or Circle

a Style may be shared by many Polygons and Circles

Delete Polygon delete PointDelete Polygon delete StyleX

UML Example (C++): AssociationUML Example (C++): AssociationX Y

class X {X(Y &y) : y_ref(y) {}void SetY(Y *y) {y_ptr = y;}void f() {y_ptr->doIt();}

...Y *y_ptr; // pointerY &y_ref; // reference

};

UML Example (C++): DependencyUML Example (C++): Dependency

X Y

class X {

...

void f1(Y y) {...; y.doIt();}

void f2(Y *y_ptr);

void f3(Y &y_ref);

};

Example: OBSort3Example: OBSort3.cpp.cpp

+getInput()+printOutput()+cleanUp()+getSize()+operator[]()

-a-size

IntArray

+sort()

Sorter

uses•getSize()•operator[]

UML Example (C++)UML Example (C++): Composition 1: Composition 1

X Y

class X {

...

Y a; // 1; Composition

Y b[10]; // 0..10; Composition

vector<Y> c; // ??

};

Java?

Composition of vector<Y>

NOT Composition of Y

UML Example (C++):UML Example (C++): Composition 2Composition 2

X Y

class X {X() { a = new Y[10]; }~X(){ delete [] a; }

...Y *a; // 0..10; Composition

};NOT Association

UML Example: OBSort3UML Example: OBSort3.cpp.cpp

+getInput()+printOutput()+cleanUp()+getSize()+operator[]()

-a-size

IntArray

+sort()

SorterContext(main)

UML Example (C++):UML Example (C++): Aggregation 1Aggregation 1

X Y

class X {X() { a = new Y[10]; }~X(){ delete [] a; }

...Y *a; // 0..n; Aggregationvector<Y> b;// Y’s are instantiated

// and destroyed by X};

The same as composition?

May be considered as aggregation of Y

UML Example (C++):UML Example (C++): Aggregation 2Aggregation 2

X vector<Y> Y

class X {...vector<Y> b;

};

X Y

Hiding implementation detail

Implementation detail

UML Example (C++): InheritanceUML Example (C++): Inheritance

class Y {...};

class X : public Y {...};

X

Y

“is a” relationship

Example: OOSort2Example: OOSort2.cpp.cpp

+getInput()+printOutput()+cleanUp()+getSize()+operator[]()

-a-size

IntArray

+sort()

SorterContext(main)

+sort()

-compareCount-exchangeCount

CountingSorter

UML Example (C++):UML Example (C++):Template ClassTemplate Class

template <class T>class X {.........};

XY

...X<Y> a;...

Abstract class

C++ static member