Resource

Effectfully allocates and releases a resource. Forms a MonadError on the resource type when the effect type has a Bracket instance. Nested resources are released in reverse order of acquisition. Outer resources are released even if an inner use or release fails.

def mkResource(s: String) = {
  val acquire = IO(println(s"Acquiring $$s")) *> IO.pure(s)
  def release(s: String) = IO(println(s"Releasing $$s"))
  Resource.make(acquire)(release)
}
val r = for {
  outer <- mkResource("outer")
  inner <- mkResource("inner")
} yield (outer, inner)
r.use { case (a, b) => IO(println(s"Using $$a and $$b")) }.unsafeRunSync

The above prints:

Acquiring outer
Acquiring inner
Using outer and inner
Releasing inner
Releasing outer

F: the effect type in which the resource is allocated and released
A: the type of resource

Source: Resource.scala

Linear Supertypes

AnyRef, Any

Abstract Value Members

abstract def allocate: F[(A, F[Unit])]

An effect that returns a tuple of a resource and an effect to release it.
An effect that returns a tuple of a resource and an effect to release it.
Streaming types might implement a bracket operation that keeps the resource open through multiple outputs of a stream.

Concrete Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def asInstanceOf[T0]: T0

Definition Classes
Any
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def hashCode(): Int

Definition Classes
AnyRef → Any
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def toString(): String

Definition Classes
AnyRef → Any
def use[B, E](f: (A) ⇒ F[B])(implicit F: Bracket[F, E]): F[B]

Allocates a resource and supplies it to the given function.
Allocates a resource and supplies it to the given function. The resource is released as soon as the resulting F[B] is completed, whether normally or as a raised error.
f
the function to apply to the allocated resource
returns
the result of applying [F] to
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

Related Docs: object Resource | package effect

sealed abstract class Resource[F[_], A] extends AnyRef

Abstract Value Members

abstract def allocate: F[(A, F[Unit])]

Concrete Value Members

final def !=(arg0: Any): Boolean

final def ##(): Int

final def ==(arg0: Any): Boolean

final def asInstanceOf[T0]: T0

def clone(): AnyRef

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def finalize(): Unit

final def getClass(): Class[_]

def hashCode(): Int

final def isInstanceOf[T0]: Boolean

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

final def synchronized[T0](arg0: ⇒ T0): T0

def toString(): String

def use[B, E](f: (A) ⇒ F[B])(implicit F: Bracket[F, E]): F[B]

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit

Inherited from AnyRef

Inherited from Any

Ungrouped