AdapterPattern

The adapter pattern is a structural design pattern that allows the interface of an existing class to be used as another interface. It enables objects with incompatible interfaces to collaborate by translating requests from the client to a form the adapted class can understand. The adapter wraps the adaptee and presents the target interface to the client, delegating calls and converting data as needed.

Key participants include the client, which uses the target interface; the target, which defines the domain-specific interface expected by the client; the adaptee, the existing class with an incompatible interface; and the adapter, which translates between the two. There are two main implementations: class adapters and object adapters. Class adapters use inheritance to adapt the interface directly, while object adapters use composition and delegation to wrap the adaptee, offering greater flexibility and compatibility with languages that do not support multiple inheritance.

Typical uses include when you want to reuse an existing class whose interface is not compatible with the rest of your code, or when integrating a library or subsystem that cannot be changed. The adapter can also provide a simplified interface to a complex subsystem.

Benefits of the adapter pattern include increased reusability of existing code, decoupling of client code from the specifics of the adaptee, and the ability to implement multiple adapters for different target interfaces. Drawbacks include added indirection, potential performance overhead, and the risk of increased complexity if overused.

In summary, the adapter pattern enables collaboration between otherwise incompatible components by translating interfaces, without modifying the existing code.