Packages

sealed abstract class ZLayer[-RIn, +E, +ROut] extends AnyRef

A ZLayer[E, A, B] describes how to build one or more services in your application. Services can be injected into effects via ZIO#provide. Effects can require services via ZIO.service."

Layer can be thought of as recipes for producing bundles of services, given their dependencies (other services).

Construction of services can be effectful and utilize resources that must be acquired and safely released when the services are done being utilized.

By default layers are shared, meaning that if the same layer is used twice the layer will only be allocated a single time.

Because of their excellent composition properties, layers are the idiomatic way in ZIO to create services that depend on other services.

Self Type
ZLayer[RIn, E, ROut]
Linear Supertypes
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Value Members

  1. final def !(implicit ev1: <:<[E, Throwable], ev2: CanFail[E], trace: Trace): ZLayer[RIn, Nothing, ROut]

    A symbolic alias for orDie.

  2. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  3. final def ##: Int
    Definition Classes
    AnyRef → Any
  4. final def +!+[E1 >: E, RIn2, ROut1 >: ROut, ROut2](that: => ZLayer[RIn2, E1, ROut2]): ZLayer[RIn with RIn2, E1, ROut1 with ROut2]
  5. final def ++[E1 >: E, RIn2, ROut1 >: ROut, ROut2](that: => ZLayer[RIn2, E1, ROut2])(implicit tag: zio.EnvironmentTag[ROut2]): ZLayer[RIn with RIn2, E1, ROut1 with ROut2]

    Combines this layer with the specified layer, producing a new layer that has the inputs and outputs of = both.

  6. def <>[RIn1 <: RIn, E1, ROut1 >: ROut](that: => ZLayer[RIn1, E1, ROut1])(implicit ev: CanFail[E], trace: Trace): ZLayer[RIn1, E1, ROut1]

    A symbolic alias for orElse.

  7. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  8. final def @@[LowerRIn <: UpperRIn, UpperRIn <: RIn, LowerE >: E, UpperE >: LowerE, LowerROut >: ROut, UpperROut >: LowerROut](aspect: => ZLayerAspect[LowerRIn, UpperRIn, LowerE, UpperE, LowerROut, UpperROut])(implicit trace: Trace): ZLayer[UpperRIn, LowerE, LowerROut]

    Returns a new layer that applies the specified aspect to this layer.

    Returns a new layer that applies the specified aspect to this layer. Aspects are "transformers" that modify the behavior of their input in some well-defined way (for example, adding a timeout).

  9. final def and[E1 >: E, RIn2, ROut1 >: ROut, ROut2](that: => ZLayer[RIn2, E1, ROut2])(implicit tag: zio.EnvironmentTag[ROut2]): ZLayer[RIn with RIn2, E1, ROut1 with ROut2]

    A named alias for ++.

  10. final def andTo[E1 >: E, RIn2 >: ROut, ROut1 >: ROut, ROut2](that: => ZLayer[RIn2, E1, ROut2])(implicit tagged: zio.EnvironmentTag[ROut2], trace: Trace): ZLayer[RIn, E1, ROut1 with ROut2]

    A named alias for >+>.

  11. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  12. final def build(scope: => Scope)(implicit trace: Trace): ZIO[RIn, E, ZEnvironment[ROut]]

    Builds a layer into a ZIO value.

    Builds a layer into a ZIO value. Any resources associated with this layer will be released when the specified scope is closed unless their scope has been extended. This allows building layers where the lifetime of some of the services output by the layer exceed the lifetime of the effect the layer is provided to.

  13. final def build(implicit trace: Trace): ZIO[RIn with Scope, E, ZEnvironment[ROut]]

    Builds a layer into a scoped value.

  14. final def catchAll[RIn1 <: RIn, E1, ROut1 >: ROut](handler: (E) => ZLayer[RIn1, E1, ROut1])(implicit trace: Trace): ZLayer[RIn1, E1, ROut1]

    Recovers from all errors.

  15. final def catchAllCause[RIn1 <: RIn, E1, ROut1 >: ROut](handler: (Cause[E]) => ZLayer[RIn1, E1, ROut1])(implicit trace: Trace): ZLayer[RIn1, E1, ROut1]

    Recovers from all errors.

  16. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @IntrinsicCandidate() @native()
  17. final def debug(prefix: => String)(implicit trace: Trace): ZLayer[RIn, E, ROut]

    Taps the layer, printing the result of calling .toString on the value.

    Taps the layer, printing the result of calling .toString on the value. Prefixes the output with the given message.

  18. final def debug(implicit trace: Trace): ZLayer[RIn, E, ROut]

    Taps the layer, printing the result of calling .toString on the value.

  19. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  20. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  21. final def extendScope: ZLayer[RIn with Scope, E, ROut]

    Extends the scope of this layer, returning a new layer that when provided to an effect will not immediately release its associated resources when that effect completes execution but instead when the scope the resulting effect depends on is closed.

  22. final def flatMap[RIn1 <: RIn, E1 >: E, ROut2](f: (ZEnvironment[ROut]) => ZLayer[RIn1, E1, ROut2])(implicit trace: Trace): ZLayer[RIn1, E1, ROut2]

    Constructs a layer dynamically based on the output of this layer.

  23. final def flatten[RIn1 <: RIn, E1 >: E, ROut1 >: ROut, ROut2](implicit tag: Tag[ROut1], ev1: <:<[ROut1, ZLayer[RIn1, E1, ROut2]], trace: Trace): ZLayer[RIn1, E1, ROut2]

    Returns a layer that performs the outer layer first, followed by the inner layer, yielding the value of the inner layer.

    Returns a layer that performs the outer layer first, followed by the inner layer, yielding the value of the inner layer.

    This method can be used to "flatten" nested layers.

  24. final def foldCauseLayer[E1, RIn1 <: RIn, ROut2](failure: (Cause[E]) => ZLayer[RIn1, E1, ROut2], success: (ZEnvironment[ROut]) => ZLayer[RIn1, E1, ROut2])(implicit ev: CanFail[E]): ZLayer[RIn1, E1, ROut2]

    Feeds the error or output services of this layer into the input of either the specified failure or success layers, resulting in a new layer with the inputs of this layer, and the error or outputs of the specified layer.

  25. final def foldLayer[E1, RIn1 <: RIn, ROut2](failure: (E) => ZLayer[RIn1, E1, ROut2], success: (ZEnvironment[ROut]) => ZLayer[RIn1, E1, ROut2])(implicit ev: CanFail[E], trace: Trace): ZLayer[RIn1, E1, ROut2]

    Feeds the error or output services of this layer into the input of either the specified failure or success layers, resulting in a new layer with the inputs of this layer, and the error or outputs of the specified layer.

  26. final def fresh: ZLayer[RIn, E, ROut]

    Creates a fresh version of this layer that will not be shared.

  27. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @IntrinsicCandidate() @native()
  28. final lazy val hashCode: Int

    Returns the hash code of this layer.

    Returns the hash code of this layer.

    Definition Classes
    ZLayer → AnyRef → Any
  29. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  30. final def launch(implicit trace: Trace): ZIO[RIn, E, Nothing]

    Builds this layer and uses it until it is interrupted.

    Builds this layer and uses it until it is interrupted. This is useful when your entire application is a layer, such as an HTTP server.

  31. final def map[ROut1](f: (ZEnvironment[ROut]) => ZEnvironment[ROut1])(implicit trace: Trace): ZLayer[RIn, E, ROut1]

    Returns a new layer whose output is mapped by the specified function.

  32. final def mapError[E1](f: (E) => E1)(implicit ev: CanFail[E], trace: Trace): ZLayer[RIn, E1, ROut]

    Returns a layer with its error channel mapped using the specified function.

  33. final def mapErrorCause[E2](h: (Cause[E]) => Cause[E2])(implicit trace: Trace): ZLayer[RIn, E2, ROut]

    Returns a layer with its full cause of failure mapped using the specified function.

    Returns a layer with its full cause of failure mapped using the specified function. This can be used to transform errors while preserving the original structure of Cause.

    See also

    catchAllCause

  34. final def memoize(implicit trace: Trace): ZIO[Scope, Nothing, ZLayer[RIn, E, ROut]]

    Returns a scoped effect that, if evaluated, will return the lazily computed result of this layer.

  35. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  36. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @IntrinsicCandidate() @native()
  37. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @IntrinsicCandidate() @native()
  38. final def orDie(implicit ev1: IsSubtypeOfError[E, Throwable], ev2: CanFail[E], trace: Trace): ZLayer[RIn, Nothing, ROut]

    Translates effect failure into death of the fiber, making all failures unchecked and not a part of the type of the layer.

  39. final def orElse[RIn1 <: RIn, E1, ROut1 >: ROut](that: => ZLayer[RIn1, E1, ROut1])(implicit ev: CanFail[E], trace: Trace): ZLayer[RIn1, E1, ROut1]

    Executes this layer and returns its output, if it succeeds, but otherwise executes the specified layer.

  40. final def retry[RIn1 <: RIn](schedule0: => Schedule[RIn1, E, Any])(implicit trace: Trace): ZLayer[RIn1, E, ROut]

    Retries constructing this layer according to the specified schedule.

  41. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  42. final def tap[RIn1 <: RIn, E1 >: E](f: (ZEnvironment[ROut]) => ZIO[RIn1, E1, Any])(implicit trace: Trace): ZLayer[RIn1, E1, ROut]

    Performs the specified effect if this layer succeeds.

  43. final def tapError[RIn1 <: RIn, E1 >: E](f: (E) => ZIO[RIn1, E1, Any])(implicit trace: Trace): ZLayer[RIn1, E1, ROut]

    Performs the specified effect if this layer fails.

  44. final def tapErrorCause[RIn1 <: RIn, E1 >: E](f: (Cause[E]) => ZIO[RIn1, E1, Any])(implicit trace: Trace): ZLayer[RIn1, E1, ROut]

    Performs the specified effect if this layer fails.

  45. final def to[E1 >: E, ROut2](that: => ZLayer[ROut, E1, ROut2])(implicit trace: Trace): ZLayer[RIn, E1, ROut2]

    A named alias for >>>.

  46. final def toRuntime(implicit ev: <:<[Any, RIn], trace: Trace): ZIO[Scope, E, Runtime[ROut]]

    Converts a layer that requires no services into a scoped runtime, which can be used to execute effects.

  47. def toString(): String
    Definition Classes
    AnyRef → Any
  48. def unit(implicit trace: Trace): ZLayer[RIn, E, Unit]

    Replaces the layer's output with Unit.

    Replaces the layer's output with Unit.

    When used with ZIO.provide and ZLayer.make macros (and their variants), this will suppress the unused layer warning that is normally emitted, and will actually include the layer for its side-effects.

  49. final def update[A >: ROut](f: (A) => A)(implicit arg0: Tag[A], trace: Trace): ZLayer[RIn, E, ROut]

    Updates one of the services output by this layer.

  50. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  51. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  52. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  53. final def zipWithPar[E1 >: E, RIn2, ROut1 >: ROut, ROut2, ROut3](that: => ZLayer[RIn2, E1, ROut2])(f: (ZEnvironment[ROut], ZEnvironment[ROut2]) => ZEnvironment[ROut3]): ZLayer[RIn with RIn2, E1, ROut3]

    Combines this layer the specified layer, producing a new layer that has the inputs of both, and the outputs of both combined using the specified function.

Deprecated Value Members

  1. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable]) @Deprecated
    Deprecated

    (Since version 9)

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