Proxy Pattern

“Provide a surrogate or placeholder for another object to control access to it.”

The Proxy pattern (GoF, 1994) interposes a wrapper object between the client and the real object. The proxy implements the same interface as the real object, so the client doesn’t know the difference.

Common variants: a virtual proxy delays expensive object creation until actually needed (lazy loading), a protection proxy controls access based on permissions, and a remote proxy represents an object in a different address space. The proxy can add caching, logging, or access checks without modifying the real object.