The Adapter pattern is a structural design pattern.
An adapter provides data/interface conversion between two classes/interfaces.
Let’s say we are developing a system for determining the buyer’s goal in a store based on neural networks. The system receives a video stream from the store’s camera, identifies buyers by their behavior, and classifies them into groups. Types of groups: came to buy (potential buyer), just to look (gaper), came to steal something (thief), came to return goods (dissatisfied buyer), came drunk/high (potential troublemaker).
Like all experienced developers, we find a ready-made neural network that can classify monkey species in a cage based on a video stream, which was kindly made freely available by the Zoological Institute of the Berlin Zoo, we retrain it on a video stream from the store and get a working state-of-the-art system.
There is only one small problem – the video stream is encoded in mpeg2 format, and our system only supports OGG Theora. We do not have the source code of the system, the only thing we can do is change the dataset and train the neural network. What to do? Write an adapter class that will translate the stream from mpeg2 -> OGG Theora and give it to the neural network.
According to the classic scheme, the pattern involves client, target, adaptee and adapter. The client in this case is a neural network receiving a video stream in OGG Theora, target is the interface with which it interacts, adaptee is the interface that outputs the video stream in mpeg2, the adapter converts mpeg2 to OGG Theora and outputs it via the target interface.
It seems simple, doesn’t it?
Sources
https://ru.wikipedia.org/wiki/Адтер_(проектированный)
https://refactoring.guru/ru/design-patterns/adapter
