Structural Modeling

Unit-3 Basic structure Modeling

Class :
A class is a fundamental concept in object-oriented software engineering that represents a real-world entity. It defines the structure (attributes/data members) and behavior (methods/functions) that the objects of that class will have. Objects are instances of a class and share the same properties and operations defined by the class.

A class is a blueprint that defines an object’s attributes and operations.

Relationship :
A relationship shows how classes are connected.

Types of relationships:

· Association – general link

· Aggregation – weak has-a

· Composition – strong has-a

· Inheritance – is-a

· Dependency – uses

Common Mechanisms:
Standard rules used to organize and explain models clearly, such as specifications, adornments, common divisions, and extensibility mechanisms.

 Specifications – detailed description of model elements

 Common Divisions – class vs object, interface vs implementation

 Extensibility Mechanisms – tagged values, constraint

Unit -4 Advance Structural Modeling

Advanced class (higher-level classes)

Is highly cohesive
Has low coupling
Follows SOLID principles
Uses abstraction, inheritance, polymorphism, and encapsulation
Often participates in design patterns

Advanced relationships in OOSE describe complex interactions between classes beyond simple association. They include inheritance (IS-A), aggregation (weak HAS-A), composition (strong HAS-A), and dependency (uses-A), helping model real-world systems effectively.

Interface (OOSE):
An interface defines a contract that specifies what methods a class must implement, without providing their implementation. It supports abstraction, multiple inheritance, and loose coupling in object-oriented design.

Types of Interfaces

1. Marker Interface – Has no methods; used to mark a class (e.g., Serializable).

2. Functional Interface – Has only one abstract method.

3. Multiple Inheritance Interface – Allows a class to implement multiple interfaces.

4. API Interface – Defines communication between system components.

Roles of Interfaces

Provides abstraction
Supports multiple inheritance
Enables loose coupling

A package is a collection of related classes, interfaces, and sub-packages grouped together to organize code and manage complexity.

Roles of Packages

1. Organize classes logically – Easier to manage large projects.

2. Avoid name conflicts – Classes with the same name can exist in different packages.

3. Control access – Public vs. private classes and members.

4. Reusability – Packages can be reused across projects.

Object Diagram (OOSE)

An Object Diagram shows a snapshot of objects and their relationships at a particular moment in time, unlike class diagrams, which show structure in general.

Milan Tomic

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