Pattern Catalog

This page is a compact navigation aid, not a substitute for studying context and consequences.

GoF patterns

Creational

Pattern	Design intent
Abstract Factory	create families of related objects without concrete-class coupling
Builder	separate construction process from representation
Factory Method	let an extension point decide what concrete object is created
Prototype	create new objects by copying configured examples
Singleton	constrain instance count and provide controlled access—use cautiously

Structural

Pattern	Design intent
Adapter	translate one interface into another expected by a client
Bridge	separate abstraction and implementation dimensions
Composite	represent part–whole hierarchies uniformly
Decorator	add responsibilities through composition
Facade	provide a simplified boundary to a subsystem
Flyweight	share intrinsic state across many fine-grained objects
Proxy	control access to another object

Behavioral

Pattern	Design intent
Chain of Responsibility	pass a request through potential handlers
Command	represent a request/action as an object
Interpreter	represent and interpret a small language/grammar
Iterator	traverse a collection without exposing representation
Mediator	centralize complex collaboration policy
Memento	capture and restore internal state safely
Observer	notify dependents of state/events
State	vary behavior with explicit state objects
Strategy	encapsulate interchangeable algorithms/policies
Template Method	define algorithm skeleton with overridable steps
Visitor	add operations across a stable element hierarchy

Pattern comparison prompts

For any two patterns that look similar, compare:

1. intent;
2. forces;
3. participants;
4. runtime collaboration;
5. axis of expected change;
6. liabilities;
7. refactoring path into/out of the pattern.