Revision Notes/Design Patterns
Field Entry - Design Patterns
Singleton Pattern
Ensures a class has only one instance throughout the entire application and provides a global point of access to it.
Field Note - Real-world Analogy
“Think of the President of a country. There is always exactly one President at a time. Everyone who wants to talk to the President goes through the same office — they don't create a new President each time.”
Field Observations - Key Topics Covered
The whole idea of Singleton is that you want exactly one object of a class to exist — no more, no less. For example, your app should have one database connection pool, one logger, or one configuration manager. Creating multiple would waste resources or cause inconsistency.
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