Design Patterns

Separate the construction of a complex object from its representation so that the same construction process can create different representations.

Ensure a class only has one instance, and provide a global point of access to it.

Postpone the creation of an object to a later point.

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

Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.

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

Composition instead of large Inheritance chains.

Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it.

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