Design Patterns

A design pattern provides a general reusable solution for the common problems occurs in software design.

Design Patterns are programming language independent strategies for solving a common problem. that means a design pattern represents an idea, your code more flexible, reusable and maintainable 🍥.

Creational design patterns :

creational design patterns are concerned with the ways of creating an object.

1. Factory Method:
Define an interface or abstract class for creating an object but let the subclasses decide which class to instantiate

2. Abstract Factory:
Define an interface or abstract class for creating families of related (or dependent) objects but without specifying their concrete sub-classes

3. Builder:

Construct a complex object from simple objects using a step-by-step approach

4. Object Pool:
Avoid expensive acquisition and release of resources by recycling objects that are no longer in use

5. Prototype:
A fully initialized instance to be copied or cloned

6. Singleton:
A class of which only a single instance can exist

Structural patterns:

Structural Design Patterns are Design Patterns that ease the design by identifying a simple way to realize relationships between entities.

1. Adapter:
Adapting an interface into another according to client expectation.

2. Bridge:
Separates an object's interface from its implementation.

3. Composite:

Allowing clients to operate on a hierarchy of objects.

4. Decorator:
Add responsibilities to objects dynamically.

5. Facade:
A single class that represents an entire subsystem, Providing an interface to a set of interfaces.

6. Flyweight:
Reusing an object by sharing it.

8. Proxy:
An object representing another object.

Behavioral Design Patterns

Behavioral design patterns are concerned with the interaction and responsibility of objects. the interaction between the objects should be in such a way that they can easily talk to each other and still should be loosely coupled.

1. Chain of responsibility:

A way of passing a request between a chain of objects.

2. Command:
Encapsulate a command request as an object.

3. Interpreter:
A way to include language elements in a program.

4. Iterator:
Sequentially access the elements of a collection.

5. Mediator:
It defines simplified communication between classes.

6. Memento:
Capture and restore an object's internal state.

7. Null Object:
Designed to act as a default value of an object.

8. Observer:
A way of notifying change to a number of classes.

9. State:
Alter an object's behavior when its state changes.

10. Strategy:
Encapsulates an algorithm inside a class.

11. Template method:
Defer the exact steps of an algorithm to a subclass.

12. Visitor:
Defines a new operation to a class without change.