Design patterns

In laymen terms, Design Patterns are the solutions to commonly occurring problems in software design. These patterns are easily re-usable and are expressive. Some types include creational, structural and behavioral.

• Creational patterns are meant to create objects instead of instantiating them directly, this includes Singleton, Prototype, Builder and Factory patterns.

• Structural which concerns class and object composition. They use inheritance to compose interfaces, which includes Decorator, Adapter, Bridge, Facade and Proxy patterns.

• Behavioral are specifically concerned with communication between objects, among which we have Iterator, Observer, Mediator and State patterns.

Examples

• Facade: A simplified API to hide low level details in a codebase.
• Proxy: substitutes an original object with another.
• Singleton: A type of object that can only be instantiate once within the codebase. An example is settings, or a database connection, and it can be represented by a class or a simple object.