PresentOptional<T> class

Implementation of an Optional with a value.

Inheritance

• Object
• Optional<T>
• PresentOptional

Properties

hashCode → int

The hash code for this object.

no setter, override

isAbsent → bool

Returns whether the value is absent.

no setter, override

isPresent → bool

Returns whether the value is present.

no setter, override

iterable → Iterable<T>

Returns an Iterable with the single present value, otherwise an empty iterable.

no setter, override

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

value → T

Returns the present value, otherwise throws a StateError.

final

valueOrNull → T?

Returns the present value if present, otherwise returns null.

no setter, override

Methods

flatMap<R>(Map1<T, Optional<R>> function) → Optional<R>

Transforms the present value of this Optional with the provided mapping function, otherwise returns an absent Optional.

override

ifAbsent(Callback0 function) → void

Evaluates the callback function if the value is absent, otherwise does nothing.

override

ifPresent(Callback1<T> function) → void

Evaluates the callback function with the present value, otherwise does nothing.

override

map<R>(Map1<T, R> function) → Optional<R>

Transforms the present value of this Optional with the provided mapping function, otherwise returns an absent Optional.

override

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

or(Map0<Optional<T>> function) → Optional<T>

Returns the current optional if present, otherwise evaluates the function callback and returns its optional.

override

orElse(T value) → T

Returns the current value if present, otherwise the argument value.

override

orElseGet(Map0<T> function) → T

Returns the current value if present, otherwise evaluates the callback function and returns its value.

override

orElseThrow([Object? error]) → T

Returns the current value if present, otherwise throws the provided error or a StateError.

override

toString() → String

A string representation of this object.

override

where(Predicate1<T> function) → Optional<T>

Returns this Optional if the provided predicate function evaluates to true, otherwise returns an absent Optional.

override

whereType<R>() → Optional<R>

Casts the present value of this Optional to R, otherwise returns an absent Optional.

override

Operators

operator ==(Object other) → bool

The equality operator.

override