1. UML Class & Object Diagram II

2. Dependency:
A relationship between two modeling elements indicates that a change in the destination may effect the source.
Example – dependency between classes: Company is dependent on Employee
Company
add(e : Employee)
Employee
The operation add has an employee object as argument: A change in Employee may inflict a change of the add operation.

3. Dependency on Package Diagram
From MagicDraw

4. Class: Describes a Set of Objects
class name
attributes compartment
operations compartment
visibility
operation signature
Point
- x : int
- y : int
+ getX() : int
+ setX(aX : int) : void
+ getY() : int
+ setY(aY : int) : void
Modelling tool: Rational Rose 2000
Coming slides will say more about visibility…
Additional compartments may be supplied, e.g., a constraints compartment.

5. Attribute/Property (Implemented as Field in Java, data member in C++)
Description of a named slot of a specified type in a class.
Each object of the class separately holds a value of the type.
<<stereotype>>opt / optvisibilityopt name multiplicityopt : typeopt …
Used if the value of the
attribute can be derived
from other information.
- (private) only the class can see
this attribute
# (protected) only the class and
all of its subclasses
+ (public) all classes that can see
the class can also see
the attribute
~ (package) only classes in the package
can see the attribute
E.g. <<unique>>
Example:
Circle: attribute radius, circumference can de derived (2 x pi x radius)
position: x, y with default values 0

6. Attribute continues
Example: Tagged value e.g. Author = Kari
… name multiplicityopt : typeopt = initial-valueopt {property-string}opt
Example: [1..*] : String
Indicating one or more addresses. (If no is present you will still have the empty string (””).) If [0..*] : String is specified, then can be null.
Example:
Circle: attribute radius, circumference can de derived (2 x pi x radius)
position: x, y with default values 0

7. Ordinary Assocaition With Navigability:
If you have a Quiz-object, the associated Question-objects can be directly reach from the Quiz-object. I.e., there will be a reference to each Question-object inside the Quiz-object but not the other way around.
Quiz
questions
Question
base class *
1..*
association with navigation
One possible mapping to Java
class Quiz{
// A list of questions
Question [] questions;
.... }
class Question {
// no reference to Quiz
.... }

8. A Class Diagram - Mapping to Java1
responsible for *
Course
Person
-name : String
-description : String
#name : String
#imail : String
#homePage : String 1
tech. responsible for * 1 * * 1
StudentCourseProfile
Student
-finished : boolean
public class Person {
protected String name;
protected String imail;
protected String homePage; //
// Navigation
protected Course[] responsibleFor;
protected Course[] techResponsibleFor; }
public class Student extends Person { //
// Navigation
public StudentCourseProfile[]
studentCourseProfile; }

9. Generalization: Eagle
A relationship between a more general element and a more specific one. For example: A bird is also an animal. (Generalization is not an association, but it do relate objects in regard to classification.)
Animal
A bird is a specialization of an animal. It inherits the structure and behaviour of Animal.
Bird
Eagle
Generalization is a transitive relation!

10. Realization:
UML: ”A semantic relationships between classifiers, in which one classifier specifies a contract that another classifier guarantees to carry out”.
<<interface>>
Movable
Snake inherits the behaviour specified by the operations of Movable (as an interface Movable has no internal structure).
move(x,y)
Snake
move(x,y)
The class Snake realises (implements)
the interface Movable.

11. Class Diagrams Defines Graph Structures

12. Association
Describes a set of links between objects, indicating some sort of connection between objects of the involved classes.
Example: A person may have friends.
:friendship
p1:Person
p2:Person f1 *
friendship
Person *
:friendship
:friendship f2
:friendship
p3:Person
p4:Person
:friendship
possible graph structure, i.e., objects with links

13. “ordinary graph” with “ordinary names”f1 *
friendship
Person * f2
defines an infinite set of graphs where the nodes are called Person and the edges are called friendship
end1
edge * *
Node
end2
“ordinary graph” with “ordinary names”
What if we need to attach some information to the edges?

14. Different Types Associations
In UML class diagrams you can distinguish between:
Ordinary Association
Aggregation (weak aggregation/shared association)
Composition (strong aggregation)

15. Aggregation/Composition
Indicates that one object contains objects of a given type, i.e., a whole/part relationship.
No cycles are allowed.
A transitive relation.
the part
the whole
aggregation
using aggregation allows
a department to be shared
among companies
Company
Department *
1..*
Composition aggregation (strong aggregation)
Company
Department 1
1..*
Must be 1 or 0..1
No limitations on this multiplicity

16. Aggregation is a weaker form of aggregation than composition
Aggregation is a weaker form of aggregation than composition. A part instance might be included in more than one aggregation at a time, which is not allowed for composition.
Company
Department
Employee 1
1..* *
1..*
a department can only belong
to one company at a time
an employee can belong to several departments at a time

17. DirectedAcyclicGraph
Composition defines a directed tree and an aggregation defines a directed graph (without cycles).
Using these properties to define a directed graph and directed tree:
DirectedAcyclicGraph
DirectedTree
0..1
0..1 *
0..1
topRoot *
predecessor
root
Node
Node
0..1
successor  *
child *
edge
edge

18. Do you see errors? DirectedAcyclicGraph Node :Directed- AcyclicGraph
0..1 * *
predecessor
Node
successor  *
:Directed- AcyclicGraph
edge
Do you see errors?
:Node
:Node
:Node
:Node
:Node
:Node
:Node
:Node

19. Do you see errors? DirectedAcyclicGraph Node :Directed- AcyclickGraph
0..1 * *
predecessor
Node
successor  *
:Directed- AcyclickGraph
edge
Do you see errors?
:Node
:Node
:Node
:Node
:Node
:Node
:Node
:Node

20. Do you see errors? DirectedTree Node :DirectedTree :Node :Node :Node
0..1
0..1
topRoot
root
Node
0..1
child *
:DirectedTree
Do you see errors?
edge
:Node
:Node
:Node
:Node
:Node
:Node
:Node
:Node

21. Do you see errors? DirectedTree Node :DirectedTree :Node :Node :Node
0..1
0..1
topRoot 1
root
Node
child *
edge
:DirectedTree
Do you see errors?
:Node
:Node
:Node
:Node
:Node
:Node
:Node
:Node

22. Deletion Characteristics
UML 2.1 specification: “… If a composite is deleted, all of its parts are normally deleted with it… deleting an element in one part of the graph will also result in the deletion of all elements of the subgraph below that element.”