1. Definition. Singleton Pattern makes sure that a class only have one instance and provide a global point of access to it. It also belongs to Creation Pattern Group. Singleton Pattern should be used where we only need one of: Thread pools, caches, dialog boxes, object that handle preferences and registry settings, objects used of… Read More »
Observer Pattern defines a one-to-many relationship between a set of objects. When the state of one object changes, all of its dependents are notified/updated automatically. It also belongs to Behavior pattern group. 1. A customized notification system. Several newspaper agencies like CNN, NYTime, BBC are subscribed to a feed of new tweets and may want… Read More »
Factory Pattern is to create object through a common interface/ abstract class. It belongs to Creational Pattern group. 1. Real-life example Suppose that we have two different types of instruments in capital market – one with an Equities and another with a Dept. A company want to use an instrument to raise capital, and represents… Read More »