Design Patterns

Design patterns are reusable solutions to commonly occurring problems in software design. They provide a way to solve problems in a structured and efficient manner, and can help to improve the quality, maintainability, and extensibility of software systems. There are many different types of design patterns, each with its own specific purpose and application. Some of the most common design patterns include:

Creational Patterns

Creational patterns provide a way to create objects in a controlled and efficient manner. They can help to reduce the complexity of object creation and ensure that objects are created in a consistent and predictable way. Some of the most common creational patterns include:

• Factory Method: This pattern defines a method for creating objects, but allows subclasses to alter the type of objects that will be created.
• Builder: This pattern separates the construction of a complex object from its representation so that the same construction process can create different representations.
• Prototype: This pattern allows you to create new objects by cloning an existing object.
• Singleton: This pattern ensures that a class has only one instance and provides a global point of access to that instance.

Structural Patterns

Structural patterns provide a way to organize and compose objects. They can help to improve the flexibility and reusability of code by allowing objects to be composed in different ways. Some of the most common structural patterns include:

• Adapter: This pattern allows objects with incompatible interfaces to work together.
• Bridge: This pattern decouples an abstraction from its implementation so that the two can vary independently.
• Composite: This pattern allows you to compose objects into tree structures to represent part-whole hierarchies.
• Decorator: This pattern allows you to add new functionality to an object without modifying the original object.
• Facade: This pattern provides a simplified interface to a complex system.
• Flyweight: This pattern reduces the number of objects created by sharing common objects instead of creating new ones.
• Proxy: This pattern provides a surrogate or placeholder for another object to control access to it.

Behavioral Patterns

Behavioral patterns provide a way to communicate and interact between objects. They can help to improve the efficiency and flexibility of code by allowing objects to communicate in a structured and predictable way. Some of the most common behavioral patterns include:

• Chain of Responsibility: This pattern allows a set of objects to handle requests in sequence until one of them handles the request or all of them have failed.
• Command: This pattern encapsulates a request as an object so that it can be parameterized, queued, logged, or undone.
• Interpreter: This pattern defines a grammar for interpreting a language and provides an interpreter to execute the grammar.
• Iterator: This pattern provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation.
• Mediator: This pattern defines an object that encapsulates how a set of objects interact.
• Observer: This pattern defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.
• State: This pattern allows an object to alter its behavior when its internal state changes.
• Strategy: This pattern defines a family of algorithms, encapsulates each one and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use it.
• Template Method: This pattern defines the skeleton of an algorithm in a method, deferring some steps to subclasses. Template Method lets subclasses redefine certain steps of an algorithm without changing the algorithm's structure.
• Visitor: This pattern allows you to define a new operation without changing the classes of the elements on which it operates.