GoF

GOF commonly refers to the Gang of Four, the four computer scientists who published the influential book Design Patterns: Elements of Reusable Object-Oriented Software in 1994. The authors—Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides—present a catalog of 23 design patterns intended to solve recurring design problems in object-oriented software. The patterns are divided into five creational patterns, seven structural patterns, and eleven behavioral patterns.

Each pattern describes a context, a problem, a solution, and the consequences of applying the pattern, often with illustrative examples. The book presents patterns in a language-agnostic way, focusing on the structure and interactions rather than specific programming syntax. Patterns are treated as reusable templates to guide design decisions rather than turnkey implementations.

Impact and reception of the GOF work have been substantial. It is widely cited in both academia and industry and has influenced the design of many programming languages, frameworks, and software development curricula. Well-known patterns such as Singleton, Factory Method, and Observer have become common terms in software engineering. While praised for clarifying common design problems and solutions, the GOF approach has also faced criticism for possible overuse or misapplication of patterns, and some argue that it may not fully address modern development practices, agile workflows, or newer architectural paradigms. Nonetheless, the GOF catalog remains a foundational reference in object-oriented design.

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