Singleton Pattern is an OOPS design pattern which is used when the requirement is to ensure that a class has only one single instance operating in the entire lifespan of the application. Effectively, the class has only one instance and provides global access to it. The Singleton pattern provides a regulated, controlled access to the active instance, and since there is only one instance accessible through a single point of access, the solution is both resource-efficient and consistent across the application.

In this design pattern, the singleton class has a private static attribute which avoids direct instantiation. Further in the class, there is a public static method which returns the desired single instance of the class. This method is used to leverage the singleton class. Unlike static classes, singleton classes support inheritance and a wide spectrum of Object Oriented Principles.

One possible real business scenario of using the Singleton Pattern is the development of a centralised logging system for a cloud-based application. The singleton pattern is employed for the logger class that governs the logging operations and ensures all messages are logged centrally; thereby providing a holistic monitoring capability and being technically efficient. On similar lines, the  Singleton Pattern can be used to develop a session manager tool for user authentication and authorisation.

It is important to understand the utilisation of the Singleton pattern. It is used where the application needs a single instance to coordinate activities across the system and needs a single point of action. Configuration management, application logging, and session management are suitable use cases. However, it is frequently used for scenarios where the singleton pattern might sound suitable, but in fact is rather problematic. Example – Database Connection Management. Using it to maintain a single connection with the database might sound relevant, but it can lead to concurrency issues and resource bottlenecks.

~S