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(Chapter 6). Unified Modeling Language (UML). Unified Modeling Language. UML October 1994 Three Amigos Grady Booch (Rational Software) [Booch] James Rumbaugh (Objectory) [OMT] Ivar Jacobson (General Electric) [OOSE] - PowerPoint PPT Presentation
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Unified Modeling Language (UML)
(Chapter 6)
Unified Modeling Language
UML October 1994 Three Amigos
Grady Booch (Rational Software) [Booch] James Rumbaugh (Objectory) [OMT] Ivar Jacobson (General Electric) [OOSE]
Modeling language = mainly graphical notation that a modeling process uses to express designs
Why Model?
Simplification of reality
Better understand a complex system visualization of the system specification of structure or behavior of the system implementational template documentation
Facilitate finding the "best" solution
Communication tool
UML is a:
Language for visualization graphical representation (static and dynamic)
Language for specifying precise, unambiguous, and complete
Language for constructing mapping from UML to OO programming language
Language for documenting requirements, architecture, design, source code, plans,
testing, prototypes, releases
Static Models in the UML(Class Diagrams)
Purpose To depict classes and their attributes (data members),
operations (methods) and relationships to other classes
Primary diagram structure Class icon: rectangle divided into three compartments
Name, attributes, operations
Various types of connecting lines depict various types of relationships with other classes
The Class Icon
ClassName
Attribute : Type
Operation() : returnType
Example: Simplest Class Diagram
Circle
radius : doublecenter : Point
setCenter(Point)setRadius(double)area() : doublecircumference() : double
An Attribute is followed by acolon and its type
An Operation is followed by acolon and its return type
Parameters are types only orname : type
This typing convention is used to create separation between the design and an implementational language.
Relationships between Classes
Where the power in a static diagram resides Association - an object of one class is connected
to objects of another class Class roles Aggregation - a "whole" object of one class is made up of
"parts," which are other objects Composition - stronger form of aggregation
Relationships between Classes (cont)
Generalization - an object of one class is a kind of object of another class Inheritance
Dependency - an object of one class uses the services of (and therefore depends on) another object of a different class
Association Represents a relationship between instances of
two classes Each association has two association ends,
attached to one of the classes in the association An end can be explicitly named with a label, or
role name.
Class A Class Brole A
role B
Roles
A role name becomes a data field name in the associated class definition
For example, role B becomes a data field name in the definition of class A
In the absence of a role name, the association end name is derived from the class attached to that end
Association and Navigability
An arrowhead on an association end indicates navigability; the target class is known about by the other class
Lack of arrowheads on an association indicates that the relationship is bidirectional
Additional notations indicate multiplicities
Multiplicities
Class1 exactly one
Class* many (zero or more)
Class0..1 optional (zero or one)
Classm..n numerically specified
Example of Associational Relationship
Game
playAgain : bool
promptPlayAgain():boolnewBoard() : Board
Board
state : long integer
update(Move)display()
0..11
board
This diagram depicts one Game being associated with zero or one Boards. The arrowhead creates a directional relationship, meaning the Game knows about the Board, but not vice versa. The name on the arrow is called a role. The numbers are called multiplicities.
Classes can be Self-Associated
data : someType
setData(someType)getData() : someType
next1Linked_List
The members of a linked-list may have differing lifetimes and their children may change. Therefore, the nodes of a linked-list have relatively weak relationships.
1
Composition: A Strong Relationship
``Has-a'' relationship When one class of object is composed of at least
one instance of another class, we say that class "is made of" or "is composed of" (at least partially) the second class
An object can be part of only one other object The multiplicity of the composing object is
always 1
Composition and Lifetimes
The composition relationship implies that the life span of the second class is coincident with that of the first class:
The constructor and destructor of the second class are called in constructor and destructor of the first class
Diagram of Compositional Relationship
Circle
radius : doublecenter : Point
setCenter(Point)setRadius(double)area() : doublecircumference():double
Point
x : doubley : double
setX(double)setY(double)getX() : doublegetY() : double
The blackened diamond represents composition. The arrowheadimplies that the Point does not know about the Circle. The rolerelationship is to provide a center point for Circle objects.Note the unnecessary redundancy in the Circle attribute box, andthe unnecessary multiplicity on the diamond.
center
1 1
More on Composition
Arrowheads restrict the directionality of relationships, like in all classes of associations
If the arrowhead had been missing in the last diagram, the implementational implication would have been that
#include "circle.H"
is withinpoint.H
so arrowheads tend to be the norm
Implementation of Composition
class Point{public:
void setX(double);void setY(double);double getX(void) const;double getY(void) const;
private:double x;double y;
};
Notice that Point knows nothing about Circles
Implementation of Composition (cont'd)
class Circle{public:
void setCenter(const Point&);void setRadius(const double);double area(void) const;double circumference(void) const;
private:double radius;Point center;
};
Here it is obvious that the Point data member lives and dies with the Circle. The Point could be implemented using a pointer, in which case it would have to be deleted in the Circle destructor.
Another Composition Example
Square Point2uLeft
lRight
setCorners(Point,Point)area() : double
class Square{public:
void setCorners(const Point&, const Point&);double area(void) const;
private:Point uLeft;Point lRight;
};
1
Aggregation
Indicated with a non-blackened diamond
Weaker than composition regarding object lifetimes
Can be represented simply through multiplicities
Aggregation Example
BinaryTree
leftChild() : BinaryTreerightChild() : BinaryTree
rChild
lChild
0..2
1
A binary tree would not be a tree, if it were not for its containing (aggregating) two of its own type. A node may contain zero to two children.
Example Structural Relationship Diagram
* *
1..*
Instructor
School Department
Student Course
11..*
1..*
* 1..*
1..*
* 1..*
1..*
0..1chairperson
0..1
Generalization Diagrams
Shows the "is-a" relationship between a general class of objects (superclass or parent) and their specializations (subclass, child or derived class)
Implies the child objects can be used in place of a parent, but not vice versa
Inherited attributes and/or operations are not repeated in the subclasses, unless they are polymorphic (virtual)
Generalization Diagrams (cont'd)
Abstract classes have names Italic font {Abstract} label next to name
Virtual operations Italic font Can also be labeled with {Abstract}
Example Generalization Diagram
Queue
maxSize: Integerfront: Integerrear: Integer
display(): voidadd(Item): voidremove(): Itemempty(): Booleanfull(): Boolean
FrontQueue FrontQueue
Item
*items
1
Example Multiple Inheritance Diagram
InterestBearing Insurable
Asset
Bank Account Real Estate Security
Checking Savings Stock Bond
Dependency
Represents a "using" relationship
Implies a change in an object of one class may effect an object in another class which uses that object
The reverse is not necessarily true
The object depended on is not contained in the depending class object
Usually implemented as member function arguments
Dependency Diagram
Board
state : Integer
updateBoard(m : Move)
Move
dir : Direction
nextMove() : Move
or
Board
state : Integer
updateBoard()
Move
dir : Direction
nextMove() : Move