UML Classes Basics

UML Classes

Definition

• A UML class represents a set of objects that share common attributes and behaviors.
• It is a blueprint or template that defines the properties and behaviors of an object.

Components

• Class Name: A unique identifier for the class.
• Attributes: Data members of the class, represented by variables or data structures.
• Operations: Functions or methods that can be performed on the class.
• Constraints: Rules or limitations that govern the behavior of the class.

Notations

• Class Box: A rectangular box that represents the class, divided into three compartments:
  1. Top: Class name
  2. Middle: Attributes
  3. Bottom: Operations
• Visibility: Indicated by symbols preceding the attribute or operation:
  • +: Public
  • -: Private
  • #: Protected
  • ~: Package (default)

Relationships

• Inheritance: A child class inherits attributes and operations from a parent class.
  • Generalization: A parent class is generalized to a child class.
  • Specialization: A child class is specialized from a parent class.
• Association: A relationship between two or more classes.
  • Aggregation: A whole-part relationship between classes.
  • Composition: A strong whole-part relationship between classes.
• Dependency: A class depends on another class, but not necessarily an association.

Best Practices

• Use meaningful and concise class names.
• Keep attributes and operations organized and easy to read.
• Use visibility symbols to control access to attributes and operations.
• Use inheritance and associations to model complex relationships between classes.

UML Classes

Definition

• UML class represents a set of objects that share common attributes and behaviors.
• It acts as a blueprint or template defining the properties and behaviors of an object.

Components

• Class name: a unique identifier for the class.
• Attributes: data members of the class represented by variables or data structures.
• Operations: functions or methods that can be performed on the class.
• Constraints: rules or limitations governing the behavior of the class.

Notations

Class Box

• A rectangular box representing the class, divided into three compartments:

Top Compartment

• Class name

Middle Compartment

• Attributes

Bottom Compartment

• Operations

Visibility

• Indicated by symbols preceding the attribute or operation:
• Public: +
• Private: -
• Protected: #
• Package (default): ~

Relationships

Inheritance

• A child class inherits attributes and operations from a parent class.
• Generalization: a parent class is generalized to a child class.
• Specialization: a child class is specialized from a parent class.

Association

• A relationship between two or more classes.
• Aggregation: a whole-part relationship between classes.
• Composition: a strong whole-part relationship between classes.

Dependency

• A class depends on another class, but not necessarily an association.

Best Practices

• Use meaningful and concise class names.
• Keep attributes and operations organized and easy to read.
• Use visibility symbols to control access to attributes and operations.
• Use inheritance and associations to model complex relationships between classes.