Singleton City is a fictitious city that is often used as an example when discussing the Singleton design pattern in computer programming. The Singleton pattern ensures that there is only one instance of a particular class created throughout the entire application, and Singleton City helps to illustrate this concept.
In Singleton City, there can only be one mayor, one police chief, one fire chief, and so on. In other words, there is only one instance of each of these classes in the entire city. This is achieved by making the constructors of these classes private, so that they cannot be directly instantiated from outside the class.
Instead, a static method or property is used to create and return the single instance of the class. This method ensures that only one instance is created and returned, even if it is called multiple times.
Singleton City is often used as a simplified example to demonstrate the Singleton pattern's benefits in various programming languages and scenarios.