Decorator Design Pattern

The Decorator Pattern is a structural design pattern that allows adding functionality to an individual object, either statically or dynamically, without affecting the behavior of other objects from the same class. This is achieved by creating a set of decorator classes that are used to wrap concrete components.

• (SOLID - Open/Closed Principle): This pattern promotes the concept that your class should be closed for modification but open for extension (SOLID - Open/Closed Principle). In other words, you can add functionality without disturbing the existing functionalities. The concept is useful when you want to add some special functionality to a specific object instead of the whole class.
• Attach additional responsibilities to an object either statically or dynamically.
• This pattern prefers object composition over inheritance. Once you master this technique, you can add new responsibilities to an object without affecting the underlying classes.

Key points of the Decorator Design Pattern:

1. Intent:

   • The main intent of the Decorator pattern is to attach additional responsibilities to an object dynamically. It provides a flexible alternative to subclassing for extending functionality.

2. Key Components:

   • Component:
     • Defines the interface for objects that can have responsibilities added to them. It's the base class for concrete components and decorators.
   • ConcreteComponent:
     • Implements the Component interface and defines the basic behavior to which decorators can add additional responsibilities.
   • Decorator:
     • Maintains a reference to a Component object and conforms to the Component interface. It has a role in both extending the component's behavior and delegating to the wrapped component.
   • ConcreteDecorator:
     • Adds new responsibilities to the component. It extends the functionality of the ConcreteComponent and conforms to the Component interface.

3. Composition over Inheritance:

   • The Decorator pattern promotes the use of composition over inheritance, allowing behavior to be added to an object by composing it with different decorators.

4. Dynamic Responsibility Addition:

   • Decorators can be stacked or removed dynamically, allowing for flexible and dynamic behavior extension at runtime.

5. Use Cases:

   • The Decorator pattern is useful when you need to add or extend the behavior of individual objects without modifying their class.
   • It is applicable when there are many possible combinations of behavior, and creating a class for each combination is impractical.

6. Advantages:

   • Flexibility: Decorators provide a flexible alternative to subclassing for extending behavior without creating an excessive number of subclasses.
   • Open/Closed Principle: The pattern follows the Open/Closed Principle, allowing new functionality to be added without altering existing code.