Mar 29th, 2023
The Proxy Pattern is a structural design pattern that allows us to provide a substitute or placeholder for another object. The Proxy Pattern provides a surrogate or placeholder object that can be used to control access to the original object. The Proxy Pattern is useful when we want to restrict or enhance access to the original object, or when we want to defer the creation of an object until it is needed.
The Proxy Pattern consists of two main components: the Subject and the Proxy objects. The Subject is the object that the client wants to interact with, while the Proxy is the object that acts as a surrogate for the Subject.
There are different types of proxies, such as remote proxies, virtual proxies, and protection proxies. Remote proxies provide a local representation of a remote object, while virtual proxies defer the creation of an object until it is needed. Protection proxies control access to an object by providing an interface for different levels of access.
Let's take an example of a media streaming service that provides access to video content. The video content is stored on remote servers and is accessed through a remote API. The application uses a VideoService object to interact with the remote API and fetch the video content.
To enhance the user experience, we can use the Proxy Pattern to create a VideoProxy object that acts as a surrogate for the VideoService object. The VideoProxy object can be used to control access to the video content and provide additional functionality such as caching.
The VideoProxy object implements the same interface as the VideoService object and delegates the requests to the VideoService object. However, before delegating the request, the VideoProxy object can perform additional tasks such as checking if the video content is already cached or if the user has the necessary access rights.
By using the Proxy Pattern, we can enhance the functionality of the VideoService object without modifying its implementation. We can also control access to the video content and provide a more efficient and scalable solution.
In conclusion, the Proxy Pattern is a powerful structural design pattern that allows us to provide a surrogate or placeholder object for another object. By using proxies, we can enhance the functionality of the original object, control access to it, or defer its creation until it is needed.