Bind
Resource
data constructor that encodes the flatMap
operation.
Resource
data constructor that encodes the flatMap
operation.
Value members
Inherited methods
Given a Resource
, possibly built by composing multiple
Resource
s monadically, returns the acquired resource, as well
as an action that runs all the finalizers for releasing it.
Given a Resource
, possibly built by composing multiple
Resource
s monadically, returns the acquired resource, as well
as an action that runs all the finalizers for releasing it.
If the outer F
fails or is interrupted, allocated
guarantees
that the finalizers will be called. However, if the outer F
succeeds, it's up to the user to ensure the returned F[Unit]
is called once A
needs to be released. If the returned
F[Unit]
is not called, the finalizers will not be run.
For this reason, this is an advanced and potentially unsafe api
which can cause a resource leak if not used correctly, please
prefer use as the standard way of running a Resource
program.
Use cases include interacting with side-effectful apis that
expect separate acquire and release actions (like the before
and after
methods of many test frameworks), or complex library
code that needs to modify or move the finalizer for an existing
resource.
- Inherited from
- Resource
Allocates two resources concurrently, and combines their results in a tuple.
Allocates two resources concurrently, and combines their results in a tuple.
The finalizers for the two resources are also run concurrently with each other, but within each of the two resources, nested finalizers are run in the usual reverse order of acquisition.
Note that Resource
also comes with a cats.Parallel
instance
that offers more convenient access to the same functionality as
both
, for example via parMapN
:
def mkResource(name: String) = {
val acquire =
IO(scala.util.Random.nextInt(1000).millis).flatMap(IO.sleep) *>
IO(println(s"Acquiring $$name")).as(name)
val release = IO(println(s"Releasing $$name"))
Resource.make(acquire)(release)
}
val r = (mkResource("one"), mkResource("two"))
.parMapN((s1, s2) => s"I have $s1 and $s2")
.use(msg => IO(println(msg)))
- Inherited from
- Resource
Applies an effectful transformation to the allocated resource. Like a
flatMap
on F[A]
while maintaining the resource context
Applies an effectful transformation to the allocated resource. Like a
flatMap
on F[A]
while maintaining the resource context
- Inherited from
- Resource
Applies an effectful transformation to the allocated resource. Like a
flatTap
on F[A]
while maintaining the resource context
Applies an effectful transformation to the allocated resource. Like a
flatTap
on F[A]
while maintaining the resource context
- Inherited from
- Resource
Implementation for the flatMap
operation, as described via the
cats.Monad
type class.
Implementation for the flatMap
operation, as described via the
cats.Monad
type class.
- Inherited from
- Resource
Given a mapping function, transforms the resource provided by this Resource.
Given a mapping function, transforms the resource provided by this Resource.
This is the standard Functor.map
.
- Inherited from
- Resource
Given a natural transformation from F
to G
, transforms this
Resource from effect F
to effect G
.
The F and G constraint can also be satisfied by requiring a
MonadCancelThrow[F] and MonadCancelThrow[G].
Given a natural transformation from F
to G
, transforms this
Resource from effect F
to effect G
.
The F and G constraint can also be satisfied by requiring a
MonadCancelThrow[F] and MonadCancelThrow[G].
- Inherited from
- Resource
Runs finalizer
when this resource is closed. Unlike the release action passed to Resource.make
, this will
run even if resource acquisition fails or is canceled.
Runs finalizer
when this resource is closed. Unlike the release action passed to Resource.make
, this will
run even if resource acquisition fails or is canceled.
- Inherited from
- Resource
Like onFinalize
, but the action performed depends on the exit case.
Like onFinalize
, but the action performed depends on the exit case.
- Inherited from
- Resource
Runs precede
before this resource is allocated.
Runs precede
before this resource is allocated.
- Inherited from
- Resource
Races the evaluation of two resource allocations and returns the result of the winner, except in the case of cancelation.
Races the evaluation of two resource allocations and returns the result of the winner, except in the case of cancelation.
- Inherited from
- Resource
Acquires the resource, runs gb
and closes the resource once gb
terminates, fails or gets interrupted
Acquires the resource, runs gb
and closes the resource once gb
terminates, fails or gets interrupted
- Inherited from
- Resource
Creates a FunctionK that can run gb
within a resource, which is then closed once gb
terminates, fails or gets interrupted
Creates a FunctionK that can run gb
within a resource, which is then closed once gb
terminates, fails or gets interrupted
- Inherited from
- Resource
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.
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.
- Value Params
- f
the function to apply to the allocated resource
- Returns
the result of applying [F] to
- Inherited from
- Resource
Allocates a resource with a non-terminating use action.
Useful to run programs that are expressed entirely in Resource
.
Allocates a resource with a non-terminating use action.
Useful to run programs that are expressed entirely in Resource
.
The finalisers run when the resulting program fails or gets interrupted.
- Inherited from
- Resource
Allocates the resource and uses it to run the given Kleisli.
Allocates the resource and uses it to run the given Kleisli.
- Inherited from
- Resource
Creates a FunctionK that, when applied, will allocate the resource and use it to run the given Kleisli.
Creates a FunctionK that, when applied, will allocate the resource and use it to run the given Kleisli.
- Inherited from
- Resource
Allocates a resource and closes it immediately.
Allocates a resource and closes it immediately.
- Inherited from
- Resource