OptionalorElselikeoptValue

OptionalorElse is a term used to describe a common programming pattern for handling optional values by providing a fallback when a value is absent. The pattern appears in languages that feature an optional or maybe type (Option, Optional, Maybe) and is centered on avoiding explicit null checks and branching based on presence.

In Java, Optional provides methods such as orElse and orElseGet. orElse returns the contained value if present, otherwise the supplied default. Because the default is evaluated eagerly, orElse can incur unnecessary work when a value is present. To defer computation, orElseGet accepts a Supplier and computes the default only if the value is absent. orElseThrow can be used to signal a missing value with an exception. These options enable concise retrieval of values while preserving null safety, but a default should generally be chosen carefully to avoid returning null.

Common use cases include configuration loading, optional results in streams, and API responses where a fallback is acceptable. Pitfalls include returning null when using orElse with a null default, or introducing hidden computation in orElse. Best practices favor orElseGet for non-trivial defaults and orElseThrow when absence is an error condition.

Other languages provide similar mechanisms, such as Kotlin's Elvis operator (?:) or Rust's unwrap_or, underscoring a universal design pattern: express "use this value if present, otherwise that one" without explicit null checks.