Page 36 - DCAP308_OBJECT_ORIENTED_ANALYSIS_AND_DESIGN

Object Oriented Analysis and Design

Notes Table 3.1: Multiplicity Indicators

Indicator Meaning
0..1 Zero or one
1 One only
0..* Zero or more
1..* One or more
n Only n (where n> 1)
0..n Zero to n (where n> 1)
1..n One to n (where n> 1)

In associations, generally movement is in both the directions of the relationships but if you
want to be specific in any particular direction, you have to mark it by an arrow.

Example: An example of multiplicity is shown in Figure 3.7.
Figure 3.7: Association and Movement
Multiplicity

Student 1 0...* Program

Movement

Self Assessment

Fill in the blanks:

6. A ..................... is a physical or conceptual connection between objects.
7. A link is also defined as an instance of an .....................
8. If a ..................... association is decomposed in some other association, some information
will be lost.
9. ..................... in an association specifies how many objects participate in a relationship.

3.3 Generalization and Inheritance

In this section, we will discuss the concepts of generalization, inheritance, and their uses in
OOM.

3.3.1 Generalization

Generalization and inheritance are powerful abstractions for sharing the structure and/or
behaviour of one or more classes.

30 LOVELY PROFESSIONAL UNIVERSITY