singleton

Singleton Pattern

Intent

Ensure a class only has one instance, and provide a global point of access to it.

Applicability

Use the Singleton pattern when

• there must be exactly one instance of a class, and it must be accessible to clients from a well-known access point.
• when the sole instance should be extensible by subclassing, and clients should be able to use an extended instance without modifying their code.

Structure

N/A

Participants

N/A

Example

N/A

Scala Tips

• Scala provides concise direct realization of the singleton pattern in the language: object

Reference

• Design Patterns: Elements of Reusable Object-Oriented Software