ZIO

Submerges the error case of an Either into the ZIO. The inverse operation of IO.either.

Accesses the environment of the effect.

val portNumber = effect.access(_.config.portNumber)

Effectfully accesses the environment of the effect.

Makes an explicit check to see if the fiber has been interrupted, and if so, performs self-interruption

When this effect represents acquisition of a resource (for example, opening a file, launching a thread, etc.), bracket can be used to ensure the acquisition is not interrupted and the resource is always released.

The function does two things:

1. Ensures this effect, which acquires the resource, will not be interrupted. Of course, acquisition may fail for internal reasons (an uncaught exception). 2. Ensures the release effect will not be interrupted, and will be executed so long as this effect successfully acquires the resource.

In between acquisition and release of the resource, the use effect is executed.

If the release effect fails, then the entire effect will fail even if the use effect succeeds. If this fail-fast behavior is not desired, errors produced by the release effect can be caught and ignored.

openFile("data.json").bracket(closeFile) { file =>
 for {
   header <- readHeader(file)
   ...
 } yield result
}

Uncurried version. Doesn't offer curried syntax and have worse type-inference characteristics, but guarantees no extra allocations of intermediate zio.ZIO.BracketAcquire and zio.ZIO.BracketRelease objects.

Acquires a resource, uses the resource, and then releases the resource. Neither the acquisition nor the release will be interrupted, and the resource is guaranteed to be released, so long as the acquire effect succeeds. If use fails, then after release, the returned effect will fail with the same error.

Uncurried version. Doesn't offer curried syntax and has worse type-inference characteristics, but guarantees no extra allocations of intermediate zio.ZIO.BracketExitAcquire and zio.ZIO.BracketExitRelease objects.

Checks the interrupt status, and produces the effect returned by the specified callback.

Checks the ZIO Tracing status, and produces the effect returned by the specified callback.

Evaluate each effect in the structure from left to right, collecting the the successful values and discarding the empty cases. For a parallel version, see collectPar.

Evaluate each effect in the structure from left to right, and collect the results. For a parallel version, see collectAllPar.

Evaluate each effect in the structure from left to right, and collect the results. For a parallel version, see collectAllPar.

Evaluate each effect in the structure from left to right, and collect the results. For a parallel version, see collectAllPar.

Evaluate effect if present, and return its result as Option[A].

Evaluate each effect in the structure from left to right, and collect the results. For a parallel version, see collectAllPar.

Evaluate each effect in the structure in parallel, and collect the results. For a sequential version, see collectAll.

Evaluate each effect in the structure in parallel, and collect the results. For a sequential version, see collectAll.

Evaluate each effect in the structure in parallel, and collect the results. For a sequential version, see collectAll.

Evaluate each effect in the structure in parallel, and collect the results. For a sequential version, see collectAll.

Evaluate each effect in the structure in parallel, and collect the results. For a sequential version, see collectAll.

Unlike collectAllPar, this method will use at most n fibers.

Evaluate each effect in the structure in parallel, and discard the results. For a sequential version, see collectAll_.

Unlike collectAllPar_, this method will use at most n fibers.

Evaluate each effect in the structure in parallel, and discard the results. For a sequential version, see collectAll_.

Evaluate and run each effect in the structure and collect discarding failed ones.

Evaluate and run each effect in the structure in parallel, and collect discarding failed ones.

Evaluate and run each effect in the structure in parallel, and collect discarding failed ones.

Unlike collectAllSuccessesPar, this method will use at most up to n fibers.

Evaluate each effect in the structure with collectAll, and collect the results with given partial function.

Evaluate each effect in the structure with collectAllPar, and collect the results with given partial function.

Evaluate each effect in the structure with collectAllPar, and collect the results with given partial function.

Unlike collectAllWithPar, this method will use at most up to n fibers.

Evaluate each effect in the structure from left to right, and discard the results. For a parallel version, see collectAllPar_.

Collects the first element of the Iterable[A] for which the effectual function f returns Some.

Evaluate each effect in the structure in parallel, collecting the the successful values and discarding the empty cases.

Evaluate each effect in the structure in parallel, collecting the the successful values and discarding the empty cases.

Unlike collectPar, this method will use at most up to n fibers.

Similar to Either.cond, evaluate the predicate, return the given A as success if predicate returns true, and the given E as error otherwise

For effectful conditionals, see ZIO.ifM

Prints the specified message to the console for debugging purposes.

Returns information about the current fiber, such as its identity.

Constructs an effect based on information about the current fiber, such as its identity.

Returns an effect that dies with the specified Throwable. This method can be used for terminating a fiber because a defect has been detected in the code.

Returns an effect that dies with a java.lang.RuntimeException having the specified text message. This method can be used for terminating a fiber because a defect has been detected in the code.

Returns an effect from a zio.Exit value.

Imports a synchronous side-effect into a pure ZIO value, translating any thrown exceptions into typed failed effects creating with ZIO.fail.

def putStrLn(line: String): Task[Unit] = Task.effect(println(line))

Imports an asynchronous side-effect into a pure ZIO value. See effectAsyncMaybe for the more expressive variant of this function that can return a value synchronously.

The callback function ZIO[R, E, A] => Any must be called at most once.

The list of fibers, that may complete the async callback, is used to provide better diagnostics.

Imports an asynchronous side-effect into a ZIO effect. The side-effect has the option of returning the value synchronously, which is useful in cases where it cannot be determined if the effect is synchronous or asynchronous until the side-effect is actually executed. The effect also has the option of returning a canceler, which will be used by the runtime to cancel the asynchronous effect if the fiber executing the effect is interrupted.

If the register function returns a value synchronously, then the callback function ZIO[R, E, A] => Any must not be called. Otherwise the callback function must be called at most once.

The list of fibers, that may complete the async callback, is used to provide better diagnostics.

Imports an asynchronous effect into a pure ZIO value. This formulation is necessary when the effect is itself expressed in terms of ZIO.

Imports an asynchronous effect into a pure ZIO value, possibly returning the value synchronously.

If the register function returns a value synchronously, then the callback function ZIO[R, E, A] => Any must not be called. Otherwise the callback function must be called at most once.

The list of fibers, that may complete the async callback, is used to provide better diagnostics.

Returns a lazily constructed effect, whose construction may itself require effects. When no environment is required (i.e., when R == Any) it is conceptually equivalent to flatten(effect(io)).

Returns a lazily constructed effect, whose construction may itself require effects. The effect must not throw any exceptions. When no environment is required (i.e., when R == Any) it is conceptually equivalent to flatten(effectTotal(zio)). If you wonder if the effect throws exceptions, do not use this method, use Task.effectSuspend or ZIO.effectSuspend.

Returns a lazily constructed effect, whose construction may itself require effects. The effect must not throw any exceptions. When no environment is required (i.e., when R == Any) it is conceptually equivalent to flatten(effectTotal(zio)). If you wonder if the effect throws exceptions, do not use this method, use Task.effectSuspend or ZIO.effectSuspend.

Returns a lazily constructed effect, whose construction may itself require effects. When no environment is required (i.e., when R == Any) it is conceptually equivalent to flatten(effect(io)).

Imports a total synchronous effect into a pure ZIO value. The effect must not throw any exceptions. If you wonder if the effect throws exceptions, then do not use this method, use Task.effect, IO.effect, or ZIO.effect.

val nanoTime: UIO[Long] = IO.effectTotal(System.nanoTime())

Accesses the whole environment of the effect.

Retrieves the executor for this effect.

Determines whether any element of the Iterable[A] satisfies the effectual predicate f.

Returns an effect that models failure with the specified error. The moral equivalent of throw for pure code.

Filters the collection using the specified effectual predicate.

Filters the Set[A] using the specified effectual predicate.

Filters the collection using the specified effectual predicate, removing all elements that satisfy the predicate.

Filters the Set[A] using the specified effectual predicate, removing all elements that satisfy the predicate.

Filters the collection in parallel using the specified effectual predicate, removing all elements that satisfy the predicate. See [[filterNot[R,E,A,Collection*]] for a sequential version of it.

Filters the Set[A] in parallel using the specified effectual predicate, removing all elements that satisfy the predicate. See filterNot for a sequential version of it.

Filters the collection in parallel using the specified effectual predicate. See [[filter[R,E,A,Collection*]] for a sequential version of it.

Filters the Set[A] in parallel using the specified effectual predicate. See [[filter[R,E,A,Collection*]] for a sequential version of it.

Returns an effectful function that extracts out the first element of a tuple.

Returns an effect that runs the first effect and in case of failure, runs each of the specified effects in order until one of them succeeds.

Returns an effect that first executes the outer effect, and then executes the inner effect, returning the value from the inner effect, and effectively flattening a nested effect.

Folds an Iterable[A] using an effectual function f, working sequentially from left to right.

Folds an Iterable[A] using an effectual function f, working sequentially from right to left.

Determines whether all elements of the Iterable[A] satisfy the effectual predicate f.

Applies the function f to each element of the Collection[A] and returns the results in a new Collection[B].

For a parallel version of this method, see foreachPar. If you do not need the results, see foreach_ for a more efficient implementation.

Applies the function f to each element of the Set[A] and returns the results in a new Set[B].

For a parallel version of this method, see foreachPar. If you do not need the results, see foreach_ for a more efficient implementation.

Applies the function f to each element of the Array[A] and returns the results in a new Array[B].

For a parallel version of this method, see foreachPar. If you do not need the results, see foreach_ for a more efficient implementation.

Applies the function f to each element of the Map[Key, Value] and returns the results in a new Map[Key2, Value2].

For a parallel version of this method, see foreachPar. If you do not need the results, see foreach_ for a more efficient implementation.

Applies the function f if the argument is non-empty and returns the results in a new Option[B].

Applies the function f to each element of the NonEmptyChunk[A] and returns the results in a new NonEmptyChunk[B].

For a parallel version of this method, see foreachPar. If you do not need the results, see foreach_ for a more efficient implementation.

Applies the function f to each element of the Collection[A] and returns the result in a new Collection[B] using the specified execution strategy.

Applies the function f to each element of the Collection[A] in parallel, and returns the results in a new Collection[B].

For a sequential version of this method, see foreach.

Applies the function f to each element of the Set[A] in parallel, and returns the results in a new Set[B].

For a sequential version of this method, see foreach.

Applies the function f to each element of the Array[A] in parallel, and returns the results in a new Array[B].

For a sequential version of this method, see foreach.

Applies the function f to each element of the Map[Key, Value] in parallel and returns the results in a new Map[Key2, Value2].

For a sequential version of this method, see foreach.

Applies the function f to each element of the NonEmptyChunk[A] in parallel, and returns the results in a new NonEmptyChunk[B].

For a sequential version of this method, see foreach.

Applies the function f to each element of the Collection[A] in parallel, and returns the results in a new Collection[B].

Unlike foreachPar, this method will use at most up to n fibers.

Applies the function f to each element of the Iterable[A] and runs produced effects in parallel, discarding the results.

Unlike foreachPar_, this method will use at most up to n fibers.

Applies the function f to each element of the Iterable[A] and runs produced effects in parallel, discarding the results.

For a sequential version of this method, see foreach_.

Optimized to avoid keeping full tree of effects, so that method could be able to handle large input sequences. Behaves almost like this code:

as.foldLeft(ZIO.unit) { (acc, a) => acc.zipParLeft(f(a)) }

Additionally, interrupts all effects on any failure.

Applies the function f to each element of the Iterable[A] and runs produced effects sequentially.

Equivalent to foreach(as)(f).unit, but without the cost of building the list of results.

Returns an effect that forks all of the specified values, and returns a composite fiber that produces a list of their results, in order.

Returns an effect that forks all of the specified values, and returns a composite fiber that produces unit. This version is faster than forkAll in cases where the results of the forked fibers are not needed.

Retrieves the scope that will be used to supervise forked effects.

Captures the fork scope, before overriding it with the specified new scope, passing a function that allows restoring the fork scope to what it was originally.

Retrieves the scope that will be used to supervise forked effects.

Lifts an Either into a ZIO value.

Creates a ZIO value that represents the exit value of the specified fiber.

Creates a ZIO value that represents the exit value of the specified fiber.

Lifts a function R => A into a URIO[R, A].

Lifts a function returning Future into an effect that requires the input to the function.

Lifts an effectful function whose effect requires no environment into an effect that requires the input to the function.

Imports a function that creates a scala.concurrent.Future from an scala.concurrent.ExecutionContext into a ZIO.

Imports a function that creates a scala.concurrent.Future from an scala.concurrent.ExecutionContext into a ZIO. The provided ExecutionContext will interrupt the Future between asynchronous operations such as map and flatMap if this effect is interrupted. Note that no attempt will be made to interrupt a Future blocking on a synchronous operation and that the Future must be created using the provided ExecutionContext.

Lifts an Option into a ZIO but preserves the error as an option in the error channel, making it easier to compose in some scenarios.

Imports a scala.concurrent.Promise we generate a future from promise, and we pass to [fromFuture] to transform into Task[A]

Lifts a Try into a ZIO.

Lifts an Option into a ZIO, if the option is not defined it fails with NoSuchElementException.

Lifts an Option into a IO, if the option is not defined it fails with Unit.

Lifts an Option into a ZIO. If the option is not defined, fail with the e value.

Returns an effect that models failure with the specified Cause.

Returns an effect that models failure with the specified Cause.

This version takes in a lazily-evaluated trace that can be attached to the Cause via Cause.Traced.

Returns the identity effectful function, which performs no effects

Runs onTrue if the result of b is true and onFalse otherwise.

Returns an effect that is interrupted as if by the specified fiber.

Prefix form of ZIO#interruptible.

Makes the effect interruptible, but passes it a restore function that can be used to restore the inherited interruptibility from whatever region the effect is composed into.

Iterates with the specified effectual function. The moral equivalent of:

var s = initial

while (cont(s)) {
 s = body(s)
}

s

Returns an effect with the value on the left part.

Returns an effect that will execute the specified effect fully on the provided executor, before returning to the default executor. See ZIO!.lock.

Loops with the specified effectual function, collecting the results into a list. The moral equivalent of:

var s  = initial
var as = List.empty[A]

while (cont(s)) {
 as = body(s) :: as
 s  = inc(s)
}

as.reverse

Loops with the specified effectual function purely for its effects. The moral equivalent of:

var s = initial

while (cont(s)) {
 body(s)
 s = inc(s)
}

Sequentially zips the specified effects using the specified combiner function.

Sequentially zips the specified effects using the specified combiner function.

Sequentially zips the specified effects using the specified combiner function.

Returns an effect that executes the specified effects in parallel, combining their results with the specified f function. If any effect fails, then the other effects will be interrupted.

Returns an effect that executes the specified effects in parallel, combining their results with the specified f function. If any effect fails, then the other effects will be interrupted.

Returns an effect that executes the specified effects in parallel, combining their results with the specified f function. If any effect fails, then the other effects will be interrupted.

Returns a memoized version of the specified effectual function.

Merges an Iterable[IO] to a single IO, working sequentially.

Merges an Iterable[IO] to a single IO, working in parallel.

Due to the parallel nature of this combinator, f must be both:

• commutative: f(a, b) == f(b, a)
• associative: f(a, f(b, c)) == f(f(a, b), c)

It's unsafe to execute side effects inside f, as f may be executed more than once for some of in elements during effect execution.

Merges an Iterable[IO] to a single IO, working in with up to n fibers in parallel.

Due to the parallel nature of this combinator, f must be both:

• commutative: f(a, b) == f(b, a)
• associative: f(a, f(b, c)) == f(f(a, b), c)

It's unsafe to execute side effects inside f, as f may be executed more than once for some of in elements during effect execution.

Lifts an Option into a IO. If the option is empty it succeeds with Unit. If the option is defined it fails with the content.

Lifts an Option into a IO. If the option is empty it succeeds with Unit. If the option is defined it fails with an error adapted with f.

Returns a new effect where boolean value of this effect is negated.

Feeds elements of type A to a function f that returns an effect. Collects all successes and failures in a tupled fashion.

Feeds elements of type A to a function f that returns an effect. Collects all successes and failures in parallel and returns the result as a tuple.

Feeds elements of type A to a function f that returns an effect. Collects all successes and failures in parallel and returns the result as a tuple.

Unlike partitionPar, this method will use at most up to n fibers.

Given an environment R, returns a function that can supply the environment to programs that require it, removing their need for any specific environment.

This is similar to dependency injection, and the provide function can be thought of as inject.

Races an IO[E, A] against zero or more other effects. Yields either the first success or the last failure.

Returns an effect that races this effect with all the specified effects, yielding the first result to complete, whether by success or failure. If neither effect completes, then the composed effect will not complete.

WARNING: The raced effect will safely interrupt the "losers", but will not resume until the losers have been cleanly terminated. If early return is desired, then instead of performing ZIO.raceFirst(l, rs), perform ZIO.raceFirst(l.disconnect, rs.map(_.disconnect)), which disconnects left and rights interrupt signal, allowing a fast return, with interruption performed in the background.

Reduces an Iterable[IO] to a single IO, working sequentially.

Reduces an Iterable[IO] to a single IO, working in parallel.

Reduces an Iterable[IO] to a single IO, working in up to n fibers in parallel.

Replicates the given effect n times. If 0 or negative numbers are given, an empty Iterable will be returned. This method is more efficient than using List.fill or similar methods, because the returned Iterable consumes only a small amount of heap regardless of n.

Performs this effect the specified number of times and collects the results.