Software design patterns are reusable solutions to common problems that software developers face during the design and development of software applications. These patterns provide a way to create structured and maintainable code by promoting best practices and facilitating communication among team members. There are several categories of design patterns, including creational, structural, and behavioral patterns.
Here are examples of design patterns from each category:
Creational Design Patterns:
Creational design patterns are a category of design patterns in software engineering that deal with object creation mechanisms, trying to create objects in a manner suitable to the situation. These patterns provide various object instantiation mechanisms to increase flexibility and reusability of existing code.
Singleton Pattern:
Ensures that a class has only one instance and provides a global point of access to that instance.
Factory Method Pattern:
Defines an interface for creating an object but allows subclasses to alter the type of objects that will be created.
Abstract Factory Pattern:
Provides an interface for creating families of related or dependent objects without specifying their concrete classes.
Builder Pattern:
Separates the construction of a complex object from its representation, allowing the same construction process to create different representations.
Prototype Pattern:
Allows you to create new objects by copying an existing object, known as a prototype.
Structural Design Patterns:
Structural design patterns are a category of design patterns in software engineering that focus on the composition of classes or objects to form larger structures while keeping those structures flexible and efficient. These patterns are concerned with relationships between objects, how objects are composed to form larger structures, and how the flexibility and efficiency of those structures can be achieved.
Adapter Pattern:
Allows the interface of one class to be used as the interface for another class.
Decorator Pattern:
Attaches additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality.
Proxy Pattern:
Provides a surrogate or placeholder for another object to control access to it.
Composite Pattern:
Composes objects into tree structures to represent part-whole hierarchies. It allows clients to treat individual objects and compositions of objects uniformly.
Bridge Pattern:
Separates an object's abstraction from its implementation so that the two can vary independently.
Behavioral Design Patterns:
Behavioral design patterns are a category of design patterns in software engineering that focus on the interaction, communication, and collaboration between objects. They deal with the responsibilities of objects and how they interact to achieve specific functionalities.
Observer Pattern:
Defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.
Strategy Pattern:
Defines a family of algorithms, encapsulates each one, and makes them interchangeable. It lets the algorithm vary independently from clients that use it.
Command Pattern:
Encapsulates a request as an object, thereby allowing for parameterization of clients with queuing, requests, and operations.
State Pattern:
Allows an object to alter its behavior when its internal state changes. The object will appear to change its class.
Chain of Responsibility Pattern:
Passes a request along a chain of handlers. Upon receiving a request, each handler decides either to process the request or to pass it to the next handler in the chain.
These are just a few examples of design patterns, and there are many more. Design patterns are not strict templates to be copied but rather guidelines and templates for solving specific types of problems in software design. They help promote code reusability, maintainability, and scalability while ensuring that your code adheres to best practices.
