According to Gang of Four Ensure a class only has one instance, and provide a global point of access to it. According to Wikipedia The singleton pattern is a design pattern that restricts the instantiation of a class to one object. So we can explain singleton pattern as follows: A singleton is a class. That class should have only one instance in… Read More »
According to Gang of Four: Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses. According to Wikipedia “The factory method pattern uses factory methods to deal with creating objects without specifying the exact class of object that will be created. This is done… Read More »
Definition: According to Gang of Four “Provide an interface for creating families of related or dependent objects without specifying their concrete classes” According to Wikipedia “The abstract factory pattern provides a way to encapsulate a group of individual factories that have a common theme without specifying their concrete classes” So we can simplify Abstract Factory Pattern as follows: Abstract… Read More »
In previous post we discussed about the definition of GOF design patterns, its essential elements and how to define them. In this post we will discuss about different types of patterns. Types of Design Pattern » Gang of four (Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides ) defined 23 patterns in their book: “Design Patterns: Elements of… Read More »
According Christopher Alexander “Each pattern describes a problem which occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice” We can simplify design pattern… Read More »