Adapter and Bridge Patterns Overview

Adapter Pattern

• The Adapter pattern allows for communication between classes with incompatible interfaces.
• The Adapter class implements the interface of the Client class while wrapping a Service class object.
• The Adapter translates calls from the Client class to the Service class, enabling communication.
• This pattern promotes flexibility, allowing the client code to work with different Adapters without modification.
• The Adapter pattern is useful when a Service class interface changes or is replaced, requiring only the creation of a new Adapter class.

Bridge Pattern

• The Bridge pattern addresses the issue of tightly coupled classes by splitting them into two hierarchies: Abstraction and Implementation.
• This pattern enhances maintainability and flexibility by allowing developers to modify one hierarchy without impacting the other.
• For example, a Shape class with subclasses Circle and Square can incorporate colors independently via Red and Blue shape subclasses, resulting in BlueCircle, RedCircle, BlueSquare, and RedSquare.
• The Bridge pattern avoids exponential growth in the number of classes required to support new shape types and colors.

Composite Pattern

• The Composite pattern offers a tree-like structure for representing both simple and complex elements through a shared interface known as a Component interface.
• Clients interact with all elements using the Component interface, simplifying interaction with both individual elements and complex structures.
• Containers delegate work to their sub-elements, process intermediate results, and return the final result to the client.

Decorator Pattern

• The Decorator pattern addresses the problem of adding new behaviors to existing objects by adding wrapper objects that contain the behaviors.
• This pattern avoids modifying the original class, promoting reusability and flexibility.
• For example, a Notifier class initially only supported email notifications, but the Decorator pattern allowed for the addition of SMS and social media notifications, improving code reusability and reducing code modifications.

Flyweight Pattern

• The Flyweight pattern optimizes memory usage by sharing common parts of objects, called intrinsic state, across multiple instances.
• The extrinsic state, passed to the Flyweight's methods, is unique to each context.
• The Flyweight Factory manages a pool of Flyweights, ensuring efficient reuse of existing instances or creating new ones when required.
• The Flyweight pattern is suitable for scenarios with a large number of similar objects in memory.

Proxy Pattern

• The Proxy pattern provides a placeholder object for another object, controlling access and allowing actions before or after requests are forwarded to the original object.
• It addresses the problem of managing large, resource-intensive objects by creating them only when needed, avoiding unnecessary code duplication.
• The Proxy class implements the same interface as the original object, allowing it to be used by clients expecting a real service object.
• The Proxy pattern enhances flexibility by enabling the execution of operations before or after the original object's processing, without altering the original code.

Strategy Pattern

• Enables the definition and interchangeability of algorithms, each encapsulated within its own class, known as a Strategy.
• This pattern prevents code duplication and ensures maintainability by separating algorithms from the main class.
• For example, a navigation application could use different route planning strategies (road, walking, public transport) without impacting the core navigation class.
• Clients can select the desired strategy, ensuring flexibility and adaptability.

This quiz explores the Adapter and Bridge design patterns, focusing on their purposes and advantages. Understand how the Adapter pattern facilitates communication between incompatible interfaces and how the Bridge pattern enhances flexibility and maintainability by separating hierarchies. Dive into practical examples to solidify your understanding of these crucial design patterns.