Decorators

Decorators are elements that modify or augment the behavior, appearance, or metadata of another object without changing its core implementation. The term is used in several domains, including the decorative arts and computer programming.

In the decorative arts, decorators are professionals who plan and execute color schemes, furnishings, textures, and accessories to enhance a space or object. They focus on aesthetics and harmony, often collaborating with clients, architects, and tradespeople. Their work differs from that of interior designers by prioritizing surface decoration and style over structural changes.

In computer programming, a decorator is a construct that wraps a function, method, or class to extend or alter its behavior. The wrapper receives the original object, delegates to it, and can add pre- or post-processing steps, or replace its output. Decorators enable patterns like logging, access control, caching, input validation, and profiling, without modifying the original code.

Implementation commonly uses higher-order functions: a decorator is a function that takes a function or class and returns a new one. In languages with syntax support, such as Python, decorators are applied with a special syntax (for example, @decorator above a function). Good practice includes preserving the wrapped object’s metadata and keeping the decoration transparent to users.

Limitations include potential difficulty in debugging, altered stack traces, and performance overhead if overused. When used judiciously, decorators aid code reuse and modularity.

See also: decorator pattern, higher-order function, syntactic sugar, caching, logging.