Design Patterns

Ensures a class has only one instance and provides a global point of access to it.

Defines an interface for creating objects, but lets subclasses decide which class to instantiate.

Separates the construction of a complex object from its representation, allowing the same construction process to create different representations.

Provides an interface for creating families of related or dependent objects without specifying their concrete classes.

Specifies the kinds of objects to create using a prototypal instance, and creates new objects by copying this prototype.

Attaches additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality.

Converts the interface of a class into another interface clients expect. Adapter lets classes work together that couldn't otherwise because of incompatible interfaces.

Composes objects into tree structures to represent part-whole hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly.

Provides a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use.

Provides a surrogate or placeholder for another object to control access to it.

Defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.

Defines a family of algorithms, encapsulates each one, and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use it.

Encapsulates a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations.

Allows an object to alter its behavior when its internal state changes. The object will appear to change its class.