UML introduction

The four of the most common diagrams

• Class diagram
• Object diagram
• Sequence diagram
• Package diagram 

It is not methodology. It is, on the other hand, a precise diagramming notation that will allow program designs to be represented and discussed. As it is graphical in nature it becomes easy to visualize  understand and discuss the information presented in the diagram. However , as the diagrams represent technical information they must be precise and clear- in order for them to work- therefore there is a precise notation that must be followed.

UML Class Diagram:

A class name consists of -

• a unique name (conventionally starting with an uppercase letter)
• a list of attributes (int,double,boolean,String etc)
• a list of methods

________________________________

                      Class name

________________________________

                      Attributes

________________________________

                     Methods()

________________________________

Attibutes and Methods visibility modifier are shown as 

+  public

-  private

#  protected

~ package

A class diagrams can make use of keywords, notes and comments.
A class diagram can show the following information:-

• Classes

- attributes
- operations
- visibility

• Relationships

- navigability
- multiplicity
- dependency
- aggregation
- composition

• Generalization/specialization

- inheritance
- interfaces

• Keywords

• Notes and Comments

1.What is Dependency ?

2. What is Simple Association?

3. What is Bidirectional Association?

4. What is Aggregation?

5. What is Composition?

Inheritance.