Singleton Pattern - Common Uses

Common Uses

• The Abstract Factory, Builder, and Prototype patterns can use Singletons in their implementation.
• Facade Objects are often Singletons because only one Facade object is required.
• State objects are often Singletons.
• Singletons are often preferred to global variables because:
  • They do not pollute the global name space (or, in languages with namespaces, their containing namespace) with unnecessary variables.
  • They permit lazy allocation and initialization, whereas global variables in many languages will always consume resources.