Adapter Design Pattern

The Adapter Design Pattern is a structural pattern that allows incompatible interfaces to work together. It acts as a bridge between two incompatible interfaces by converting the interface of a class into another interface that a client expects. This pattern involves a single class called Adapter, which is responsible for joining functionalities of independent or incompatible interfaces.

key points of the Adapter Design Pattern:

1. Intent:

   • The main intent of the Adapter pattern is to allow objects with incompatible interfaces to interact. It acts as a bridge, making one interface compatible with another without modifying the existing code.

2. Key Components:

   • Target:
     • Defines the interface that the client uses. It represents the desired interface that the client expects.
   • Adapter:
     • Implements the Target interface and wraps the Adaptee, making it compatible with the Target interface.
   • Adaptee:
     • Defines an existing interface that needs to be adapted. It's the class that the client can't use directly.
   • Client:
     • Interacts with the Target interface. It is unaware of the Adapter and communicates directly with the Target.

3. Class and Object Adapters:

   • There are two main ways to implement the Adapter pattern: class adapters, which use multiple inheritance or interfaces, and object adapters, which use composition.

4. Adapter Interface:

   • The Adapter implements the Target interface, which is the interface expected by the client. It delegates calls to the corresponding methods in the Adaptee.

5. Compatibility:

   • The Adapter makes the Adaptee's interface compatible with the Target interface, allowing the client to interact with the Adaptee through the Adapter.

6. Advantages:

   • Reusability: The Adapter pattern allows the reuse of existing classes with incompatible interfaces.
   • Flexibility: It provides a way to make classes work together that wouldn't otherwise be able to due to incompatible interfaces.

7. Use Cases:

   • The Adapter pattern is suitable when integrating new components with existing systems that have different interfaces.
   • It is useful when you want to reuse existing classes with interfaces that are not compatible with the rest of your codebase.

Example:

• Consider a system that uses a European electrical socket (Adaptee) and you have a device with a U.S. plug (Client). An adapter (Adapter) can be used to make the U.S. plug compatible with the European socket.