abstract class Callback[-E, -A] extends (Either[E, A]) => Unit
Represents a callback that should be called asynchronously with the result of a computation.
This is an Either[E, A] => Unit with an OOP interface that
avoids extra boxing, along with overloads of apply.
The onSuccess method should be called only once, with the successful
result, whereas onError should be called if the result is an error.
Obviously Callback describes unsafe side-effects, a fact that is
highlighted by the usage of Unit as the return type. Obviously
callbacks are unsafe to use in pure code, but are necessary for
describing asynchronous processes.
THREAD-SAFETY: callback implementations are NOT thread-safe by contract, this depends on the implementation. Callbacks can be made easily thread-safe via wrapping with:
NOTE that callbacks injected in the Task async builders (e.g. Task.async) are thread-safe.
- Source
- Callback.scala
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Instance Constructors
- new Callback()
Abstract Value Members
- abstract def onError(e: E): Unit
Signals an error.
Signals an error.
Can be called at most once by contract. Not necessarily thread-safe, depends on implementation.
- abstract def onSuccess(value: A): Unit
Signals a successful value.
Signals a successful value.
Can be called at most once by contract. Not necessarily thread-safe, depends on implementation.
Concrete Value Members
- def andThen[A](g: (Unit) => A): (Either[E, A]) => A
- Definition Classes
- Function1
- Annotations
- @unspecialized()
- def apply(result: Try[A])(implicit ev: <:<[Throwable, E]): Unit
Signals a value via Scala's
Try.Signals a value via Scala's
Try.Can be called at most once by contract. Not necessarily thread-safe, depends on implementation.
- def apply(result: Either[E, A]): Unit
Signals a value via Scala's
Either(Leftis error,Rightis the successful value).Signals a value via Scala's
Either(Leftis error,Rightis the successful value).Can be called at most once by contract. Not necessarily thread-safe, depends on implementation.
- Definition Classes
- Callback → Function1
- def compose[A](g: (A) => Either[E, A]): (A) => Unit
- Definition Classes
- Function1
- Annotations
- @unspecialized()
- def contramap[B](f: (B) => A): Callback[E, B]
Return a new callback that will apply the supplied function before passing the result into this callback.
- def toString(): String
- Definition Classes
- Function1 → AnyRef → Any
- def tryApply(result: Either[E, A]): Boolean
Attempts to call Callback.apply.
Attempts to call Callback.apply.
In case the underlying callback implementation protects against protocol violations, then this method should return
falsein case the final result was already signaled once via onSuccess or onError.The default implementation relies on catching
CallbackCalledMultipleTimesException in case of violations, which is what thread-safe implementations of
onSuccessoronErrorare usually throwing.WARNING: this method is only provided as a convenience. The presence of this method does not guarantee that the underlying callback is thread-safe or that it protects against protocol violations.
- def tryApply(result: Try[A])(implicit ev: <:<[Throwable, E]): Boolean
Attempts to call Callback.apply.
Attempts to call Callback.apply.
In case the underlying callback implementation protects against protocol violations, then this method should return
falsein case the final result was already signaled once via onSuccess or onError.The default implementation relies on catching
CallbackCalledMultipleTimesException in case of violations, which is what thread-safe implementations of
onSuccessoronErrorare usually throwing.WARNING: this method is only provided as a convenience. The presence of this method does not guarantee that the underlying callback is thread-safe or that it protects against protocol violations.
- def tryOnError(e: E): Boolean
Attempts to call Callback.onError.
Attempts to call Callback.onError.
In case the underlying callback implementation protects against protocol violations, then this method should return
falsein case the final result was already signaled once via onSuccess or onError.The default implementation relies on catching
CallbackCalledMultipleTimesException in case of violations, which is what thread-safe implementations of
onSuccessoronErrorare usually throwing.WARNING: this method is only provided as a convenience. The presence of this method does not guarantee that the underlying callback is thread-safe or that it protects against protocol violations.
- def tryOnSuccess(value: A): Boolean
Attempts to call Callback.onSuccess.
Attempts to call Callback.onSuccess.
In case the underlying callback implementation protects against protocol violations, then this method should return
falsein case the final result was already signaled once via onSuccess or onError.The default implementation relies on catching
CallbackCalledMultipleTimesException in case of violations, which is what thread-safe implementations of
onSuccessoronErrorare usually throwing.WARNING: this method is only provided as a convenience. The presence of this method does not guarantee that the underlying callback is thread-safe or that it protects against protocol violations.
This is the API documentation for the Monix library.
Package Overview
monix.execution exposes lower level primitives for dealing with asynchronous execution:
Atomictypes, as alternative tojava.util.concurrent.atomicmonix.catnap exposes pure abstractions built on top of the Cats-Effect type classes:
monix.eval is for dealing with evaluation of results, thus exposing Task and Coeval.
monix.reactive exposes the
Observablepattern:Observableimplementationsmonix.tail exposes Iterant for purely functional pull based streaming:
BatchandBatchCursor, the alternatives to Scala'sIterableandIteratorrespectively that we are using within Iterant's encodingYou can control evaluation with type you choose - be it Task, Coeval, cats.effect.IO or your own as long as you provide correct cats-effect or cats typeclass instance.