Maybe<T> class abstract

A variation of the Maybe monad with eager execution.

Implementers

• Just
• Nothing

Constructors

Maybe()

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

as<R>() → Maybe<R>

WARNING! This method is experimental and may be removed in the future versions. Forceful typecast to R.

chain(Maybe<T> next) → Maybe<T>

If this is Nothing, returns next. Otherwise return this..

fallback(Maybe<T> next()) → Maybe<T>

If this is Nothing, returns the result of next. Otherwise return this..

flatMap<P>(Maybe<P> mapper(T value)) → Maybe<P>

Maps the value to P.

ifNothing(void callback()) → Maybe<T>

Calls the callback function if the wrapped value is not present.

ifPresent(void consumer(T value)) → Maybe<T>

Calls the consumer if the wrapped value is present.

map<P>(P mapper(T value)) → Maybe<P>

Maps the value to P.

merge<R, V>(Maybe<V> other, Merger<R, T, V> merger) → Maybe<R>

If this and the other are both Just values, merges them using the merger function and returns Just

merge2<R, V1, V2>(Maybe<V1> v1, Maybe<V2> v2, Merger2<R, T, V1, V2> merger) → Maybe<R>

Same as merge, but with 2 arguments.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

or(T defaultValue) → T

Returns the wrapped value (if present), or the defaultValue.

orAsync(Future<T> defaultValue) → Future<T>

Returns a Future of the wrapped value (if present), or the defaultValue.

orGet(T producer()) → T

Returns the wrapped value (if present), or the result of the producer.

orGetAsync(Future<T> producer()) → Future<T>

Returns a Future of the wrapped value (if present), or the result of the producer.

orThrow(Object producer()) → T

Returns the wrapped value (if present), or throws the result of the producer.

toString() → String

A string representation of this object.

inherited

tryMap<P>(P mapper(T value)) → Maybe<P>

Tries to map value to P. If the mapper throws anything (not just an Exception), returns Nothing<P>.

type<P>() → Maybe<P>

Narrows the type to P if the value is present and has actually the type of P.

where(bool predicate(T value)) → Maybe<T>

Filter the value using the predicate.

Operators

operator ==(Object other) → bool

The equality operator.

inherited