🛡️ Proxy Pattern

📌 What is the Proxy Pattern?

The Proxy Pattern is a structural design pattern that provides a surrogate or placeholder for another object to control access to it. A proxy acts as an intermediary, allowing you to perform additional logic before, after, or instead of forwarding the request to the original object.

🛠️ Key Concepts:

1. Subject → Defines the common interface for both the RealSubject and the Proxy. This interface outlines the methods that the client can use to interact with the Subject through either the Proxy or directly with the RealSubject.
2. Real Subject → The actual object that contains the core business logic. The Proxy represents and controls access to this object.
3. Proxy → A class that implements the same interface as the RealSubject and holds a reference to it. The Proxy controls access to the RealSubject and can add extra behavior (such as access control, logging, lazy initialization, etc.) before or after invoking methods on the RealSubject.

🔥 When to Use?

✅ When you need to control access to an object. The Proxy pattern lets you execute additional logic before or after the access to the real object. ✅ When you require lazy initialization. A Proxy can defer the creation of the RealSubject object until it's actually needed. ✅ When you want to improve performance. A Proxy can postpone heavy or costly operations, or cache results from the real object. ✅ When you want to implement access control. A Protection Proxy can check permissions and access levels before granting access to the RealSubject. ✅ When you want to add logging or monitoring to object operations. A Smart Proxy can log or monitor information before and after calls to methods of the RealSubject.

🎯 Real-World Examples:

• Proxy Server 🌐 (A proxy server acts as an intermediary between a client and a backend server, filtering requests, caching content, or enhancing security.)
• Image Proxy 🖼️ (For displaying large images, an image proxy can show a low-resolution version initially and then load the high-resolution image in the background.)
• Virtual Proxy 💾 (For heavyweight objects, a virtual proxy can delay the creation of the object until it is truly needed, saving resources until necessary.)
• Protection Proxy 🔒 (For controlling access to sensitive resources, a protection proxy can check user permissions before allowing access.)
• Smart Proxy (Smart Reference) 💡 (To add additional logic like reference counting or logging when accessing an object.)

💡 Benefits:

✔ Access Control – Enables fine-grained control and management of access to the real object. ✔ Lazy Initialization – Delays object creation until it's actually needed, potentially improving startup performance. ✔ Performance Enhancements – Improves performance through caching or deferring expensive operations. ✔ Enhanced Security – Increases system security by implementing access control and permission checks. ✔ Decoupling – Clients interact with the Proxy and remain decoupled from the implementation details of the RealSubject.

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🔗 Example Code: See Implementation