Creational design patterns manage object creation to improve flexibility and code reuse. They decouple a system from concrete classes, making changes or extensions easier. The goal is to abstract instantiation, control creation, and ensure consistency.

The Singleton Pattern

This pattern ensures a class has only one instance with a global access point. It's often used for configuration, logging, and database connections, preventing conflicts and ensuring controlled access. Pseudo-code for it might look something like this:

The Factory Method

This pattern defines an interface for object creation but lets subclasses decide which class to instantiate. It's useful when the system must choose the object type at runtime. For example a notification system creating email, SMS, or push notifications based on user preference. Pseudo-code for Factory Method:

The Abstract Factory

This pattern provides an interface for creating related objects without specifying concrete classes. It’s useful when components must work together but remain interchangeable. For example, a UI toolkit producing matching elements for light or dark themes. Pseudo-code for Abstract Factory:

The Builder pattern

This one constructs complex objects step by step, separating construction from representation. This allows the same process to produce different results. For example, building a PDF, Word document, or HTML file with the same steps. Pseudo-code for Builder:

These patterns are chosen based on object creation needs, as well as the need for control, variation, and separating construction logic from representation.

Understanding creational design patterns helps architects manage dependencies and complexity early in development. Used correctly, they reduce duplication, ensure consistency, and prepare the architecture for growth and change.