Singleton Pattern

The singleton pattern can look clean and elegant when considered in isolation. The article frames singletons as a possible recurrence of tight-coupling problems after god objects are addressed. The Singleton pattern ensures that a given class has only one instance throughout the lifetime of the application. The Singleton pattern ensures that a class has only one instance throughout the lifetime of a program and provides a single global point of access to that instance. Overusing a singleton across a stack can turn it into a bottleneck and hidden coupling point. Singleton-related problems can be difficult to trace back to the pattern itself. Singleton is appropriate for resources or services where having multiple instances would cause conflicts or inconsistencies. Configuration managers, logging services, and connection pools are common examples of Singleton use cases. The Singleton pattern is appropriate when exactly one controlling entity must exist, as multiple competing instances would cause conflicting behavior.