A Humorous Overview of 23 Classic Software Design Patterns

01 Factory Method

Just like ordering chicken wings at fast‑food restaurants, the Factory Method separates the client from the concrete product creation; the client asks the factory for a product without needing to know which specific class is instantiated.

02 Builder

The Builder pattern works like a multilingual translation device: each button corresponds to a language, allowing the client to obtain the same phrase (“I love you”) in different forms without knowing the construction details.

03 Abstract Factory

When ordering a burger with a specific taste, the client tells the server what they want, while the server (the abstract factory) decides which concrete product to provide, delegating creation to subclasses.

04 Prototype

Prototype works like copying pre‑written love messages: a ready‑made object (the prototype) is cloned to produce new instances without building them from scratch.

05 Singleton

The Singleton ensures that only one instance of a class exists in the whole system, similar to being the sole husband for multiple wives.

06 Adapter

An Adapter converts one interface into another so that incompatible classes can work together, like a friend translating between Cantonese and Mandarin.

07 Bridge

Bridge decouples abstraction from implementation, allowing them to vary independently, just as you combine different greetings for various situations without hard‑coding each case.

08 Composite

Composite organizes objects into a tree structure so that clients can treat individual objects and compositions uniformly, like buying a set of gifts as a single package.

09 Decorator

Decorator adds responsibilities to objects dynamically without affecting other objects, similar to wrapping a photo in a decorative frame and box.

10 Facade

Facade provides a simplified high‑level interface to a complex subsystem, like switching a camera to auto mode so a non‑expert can take pictures easily.

11 Flyweight

Flyweight shares common intrinsic state among many fine‑grained objects while keeping extrinsic state separate, reducing memory usage.

12 Proxy

Proxy supplies a surrogate that controls access to the real subject, handling routine requests automatically and delegating others to the client.

13 Chain of Responsibility

Requests travel along a chain of handlers until one processes them, allowing dynamic re‑ordering of responsibilities.

14 Command

Command encapsulates a request as an object, separating the invoker from the executor and enabling actions like undo.

15 Interpreter

Interpreter defines a grammar for a language and provides a way to evaluate sentences in that language.

16 Iterator

Iterator provides a way to access elements of a collection sequentially without exposing its internal structure.

17 Mediator

Mediator centralizes complex communications between objects, reducing direct dependencies and simplifying interaction.

18 Memento

Memento captures an object's internal state so it can be restored later without violating encapsulation.

19 Observer

Observer establishes a one‑to‑many dependency so that when the subject changes, all observers are automatically notified.

20 State

State allows an object to alter its behavior when its internal state changes, appearing as if the object changed its class.

21 Strategy

Strategy defines a family of algorithms, encapsulates each one, and makes them interchangeable to vary behavior at runtime.

22 Template Method

Template Method outlines the skeleton of an algorithm in a base class, letting subclasses fill in the concrete steps.

23 Visitor

Visitor separates operations from the object structure, allowing new operations to be added without modifying the elements.