What is the Proxy design pattern and when should it be used?

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What is the Proxy design pattern and when should it be used?

The Proxy design pattern is a structural design pattern that provides a surrogate or placeholder for another object to control access to it. It involves creating a class that acts as an intermediary between the client and the real object, allowing the proxy object to control access to the real object and perform additional tasks before or after accessing it.

The Proxy design pattern should be used in the following scenarios:

1. Remote Proxy: When the real object resides in a different address space, such as a remote server, and needs to be accessed over a network. The proxy object acts as a local representative for the remote object, handling the communication and data transfer between the client and the remote object.

2. Virtual Proxy: When creating the real object is expensive or resource-intensive, and it is not necessary to create it until it is actually needed. The proxy object acts as a placeholder for the real object and delays its creation until the client requests it.

3. Protection Proxy: When access to the real object needs to be controlled or restricted. The proxy object can perform authentication, authorization, or other security-related tasks before allowing the client to access the real object.

4. Smart Proxy: When additional functionality or behavior needs to be added to the real object without modifying its code. The proxy object can intercept method calls to the real object and perform additional tasks, such as caching, logging, or lazy loading.

Overall, the Proxy design pattern provides a flexible and modular way to control access to objects, add additional functionality, and improve performance or security in various scenarios.