OOAD - UML - Class and Object Diagrams - Lab

1. Class Diagram
Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

2. Class and Object Diagrams
Lab Material
Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

3. Class Diagram
 A class diagram shows a set of classes, interfaces, and
collaborations and their relationships.
 Class diagrams commonly contain the following things:
 Classes
 Interfaces
 Collaborations
 Dependency
 Generalization, and
 Association relationships
 Aggregation
 Composition
 Multiplicity
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

4. Class Diagram
 A class diagram shows a set of classes, interfaces, and
collaborations and their relationships.
 Class diagrams commonly contain the following things:
 Classes
 Interfaces
 Collaborations
 Dependency
 Generalization, and
 Association
 Aggregation
 Composition
 Multiplicity
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

5. Steps involved
 Study the given problem statement
 Identify the classes
 Identify the attributes and behaviors (properties and methods)
 Denote visibility, data type, argument and return value type
 Identify the relationships
 Denote Relationships details
 Relationship name
 Role
 Relation direction
 Multiplicity
 Identify the possible Interface (common must methods for set of
classes) and relate
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

6. Study the given problem statement
Develop an automated student registration system. The students
registration system identify the School (i.e. Arts & Sciences,
Engineering, Fine Arts, etc.) in which the student is registered. The
school offer both undergraduate and graduate programs. It also shall
Identify the current courses offered by each department and the
instructor engaged to each class to handle the course.
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

7. Identify the classes
Develop an automated student registration system. The students
registration system identify the School (i.e. Arts & Sciences,
Engineering, Fine Arts, etc.) in which the student is registered. The
school offer both undergraduate and graduate programs. It also shall
Identify the current courses offered by each department and the
instructor engaged to each class to handle the course.
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

8. Identify the classes
school
student
undergraduate
graduate
programs
courses
department
instructor
class
course
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

9. Identify the attributes and behaviors
Develop an automated student registration system. The students
registration system identify the School (i.e. Arts & Sciences,
Engineering, Fine Arts, etc.) in which the student is registered. The
school offer both undergraduate and graduate programs. It also shall
Identify the current courses offered by each department and the
instructor engaged to each class to handle the course.
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

10. Identify the classes
School
-name : String
-address : String
-id : int
-startdate : Date
+school(int id, String name):
+addStudent():bool
+removeStudent(int):bool
name
attributes
operations
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

11. Denote visibility, data type…..
1. Public: Any outside classifier can use (+).
2. Protected: Any descendant of the classifier can use (#).
3. Private: Only the classifier itself can use (-).
4. Protected: public within package (~)
1. Instance: Each instance of the classifier holds its own value
for the feature.
2. Class variable: There is just one value of the feature for all
instances of the classifier. (static variable)
static variable should be underlined
* Derived variables should precede /
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

12. Identify the relationships
 Generalization
 Association (general) – name, role, direction, multiplicity
 Special types:
 Aggregation (parts can exist without whole)
 Composition (parts cant exist without whole)
 Realization
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

13. Identify the relationships
 Generalization
 Use to show a parent-child relationship.
Student
……
generalization
+handleClass():void
Graduate student
+attenMidexam():void
Undergraduate student
……
-ug:String
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

14. Identify the relationships
 Generalization
Shape
SplineEllipsePolygon
Shape
SplineEllipsePolygon
Shared Target Style
Separate Target Style
. . .
. . .
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

15. Identify the relationships
 Association (general) – name, role, direction, multiplicity
Instructor CourseTeaches
Name an association to describe its nature.
Direction triangle: direction of reading.
Instructor Course
Role: face presented to the other class.
teacher subject taught
Person Company
employee employer
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

16. Identify the relationships
 Association (general) – name, role, direction, multiplicity
Instructor Course
teacher Subject taught
1..2 0..3
Multiplicity: How many objects may be connected across
an instance of an association.
Multiplicity at one end  for each object at the other end,
there must be that many objects at the near end.
Exactly one: 1
Zero or one: 0 .. 1
Many: 0 .. *
One or more: 1 .. *
Not shown  unspecified or suppressed 16
Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

17. Identify the relationships
 Aggregation (general) – name, role, direction, multiplicity
1
0..*
Department
Instructor
whole
part
1
1..*
Team
Player
whole
part
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

18. Identify the relationships
 Composition (general) – name, role, direction, multiplicity
1
0..*
Account
Order
whole
part
1
1..*
School
Department
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

19. Identify the possible Interface
 Identify one or more classes that
must have a set of common
operations.
 Create interface with the set of
common operations (abstract).
 Relate the classes and the interface
by Realization.
 Defines a set of operation specs
 Never defines an implementation
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

20. student registration system
name
address
...
addstudent()
removestudent()
...
School
name
studentID
Student
1..*
*
Graduate UnderGraduate
name
Department
description
Course
name
Instructor
Offers
1
1..*
Attends >
< Teaches
has
1..*1
* * 1..3 1
Assigned To ^
Chair
1
0..1
0..1
Schedule
accepted
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

21. Example 1
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

22. Example 2
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

23. Example 3
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

24. Example 4
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

25. Example 5
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

26. Example 6
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

27. Steps involved
 Study the given problem statement
 Identify the classes
 Identify the attributes and behaviors (properties and methods)
 Denote visibility, data type, argument and return value type
 Identify the relationships
 Denote Relationships details
 Relationship name
 Role
 Relation direction
 Multiplicity
 Identify the possible Interface (common must methods for set of
classes) and relate
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

28. Object Diagram
Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

29. Object Diagram
 Object diagrams model the instances of things contained in class
diagrams.
 An object diagram shows a set of objects and their relationships
at a point in time.
 This involves modeling a snapshot of the system at a moment in
time and rendering a set of objects, their state, and their
relationships.
 An object diagram covers a set of instances of the things found in
a class diagram.
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

30. Object Representation
 In class diagram elements are in abstract form to represent the
blue print and
 in object diagram the elements are in concrete form to represent
the real world object.
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

31. How to model Object Diagram
 an object diagram is an instance of a class diagram.
 It implies that an object diagram consists of instances of things
used in a class diagram.
 So both diagrams are made of same basic elements but in
different form.
 To capture a particular system, numbers (classes) of class
diagrams are limited.
 However, if we consider object diagrams then we can have
unlimited number of instances, which are unique in nature.
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

32. How to model Object Diagram
 a single object diagram cannot capture all the necessary
instances or rather cannot specify all the objects of a system.
 Hence, the solution is −
1. First, analyze the system and decide which instances have important
data and association.
2. Second, consider only those instances, which will cover the
functionality.
3. Third, make some optimization as the number of instances are
unlimited.
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

33. Things to be decided
 the following things are to be decided before starting the
construction of the diagram,
1. The object diagram should have a meaningful name to indicate its
purpose.
2. The most important elements are to be identified.
3. The association among objects should be clarified.
4. Values of different elements need to be captured to include in the
object diagram.
5. Add proper notes at points where more clarity is required.
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

34. Class and Object Diagram 1
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

35. Class and Object Diagram 2
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

36. Class and Object Diagram 3
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

37. Class and Object Diagram 4
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

38. Class and Object Diagram 5
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

39. Example – Class Diagram
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

40. Example – Object Diagram
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

41. Lets Try..!
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

42. Class vs Object Diagram
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

43. The End
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

44. Some Clarifications
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

45. Some Clarifications
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

46. Some Clarifications
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

47. Some Clarifications
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

48. Some Clarifications
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam

49. The End…
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Dr. P. Victer Paul, Indian Institute of Information Technology Kottayam