Tutorial by Examples

Singletons are used to ensure that only one instance of an object is being created. The singleton allows only a single instance of itself to be created which means it controls its creation. The singleton is one of the Gang of Four design patterns and is a creational pattern. Thread-Safe Singleton ...

Singletons in Java are very similar to C#, being as both languages are object orientated. Below is an example of a singleton class, where only one version of the object can be alive during the program's lifetime (Assuming the program works on one thread) public class SingletonExample { priva...

As per Wiki : In software engineering, the singleton pattern is a design pattern that restricts the instantiation of a class to one object. This is required to create exactly one object to coordinate actions across the system. class Singleton { // Private constructor so it can not be arbitra...

Real life use cases for Singleton pattern; If you are developing a client-server application, you need single instrance of ConnectionManager, which manages the life cycle of client connections. The basic APIs in ConnectionManager : registerConnection: Add new connection to existing list of connec...

Static initialization is suitable for most situations. When your application must delay the instantiation, use a non-default constructor or perform other tasks before the instantiation, and work in a multithreaded environment, you need a different solution. Cases do exist, however, in which you cann...

Example from phptherightway.com <?php class Singleton { /** * @var Singleton The reference to *Singleton* instance of this class */ private static $instance; /** * Returns the *Singleton* instance of this class. * * @return Singleton The *Sing...

Note: The singleton is a design pattern. But it also considered an anti-pattern. The use of a singleton should be considered carefully before use. There are usually better alternatives. The main problem with a singleton is the same as the problem with global variables. They introduce external glo...