The state pattern is a behavioral design pattern. According to GoF definition, a state allows an object to alter its behavior when its internal state changes. The object will appear to change its class. It can be drawn from above definition that there shall be a separate concrete class per possible state of an object. […]
Mediator helps in establishing loosely coupled communication between objects and helps in reducing the direct references to each other.
According to GoF definition, observer pattern defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically. It is also referred to as the publish-subscribe pattern. In observer pattern, there are many observers (subscriber objects) that are observing a particular subject (publisher object). Observers register […]
Memento design pattern is behavioral pattern and one of 23 design patterns discussed by Gang of Four. Memento pattern is used to restore state of an object to a previous state. It is also known as snapshot pattern. A memento is is like a restore point during the life cycle on the object, which the […]
An iterator design pattern provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation.