Haxl.Core.StateStore

Most users should import Haxl.Core instead of importing this module directly.

Documentation

class Typeable f => StateKey (f :: Type -> Type) where

StateKey maps one type to another type. A type that is an instance of StateKey can store and retrieve information from a StateStore.

Minimal complete definition

Nothing

Associated Types

data State f

Methods

getStateType :: Proxy f -> TypeRep

We default this to typeOf1, but if f is itself a complex type that is already applied to some paramaters, we want to be able to use the same state by using typeOf2, etc

Instances

Typeable tag => StateKey (ConcurrentIOReq tag)

Defined in Haxl.DataSource.ConcurrentIO

Associated Types

data State (ConcurrentIOReq tag)

Methods

getStateType :: Proxy (ConcurrentIOReq tag) -> TypeRep

data StateStore

The StateStore maps a StateKey to the State for that type.

Instances

Semigroup StateStore

Defined in Haxl.Core.StateStore

Methods

(<>) :: StateStore -> StateStore -> StateStore

sconcat :: NonEmpty StateStore -> StateStore

stimes :: Integral b => b -> StateStore -> StateStore

Monoid StateStore

Defined in Haxl.Core.StateStore

Methods

mempty :: StateStore

mappend :: StateStore -> StateStore -> StateStore

mconcat :: [StateStore] -> StateStore

stateGet :: forall r. StateKey r => StateStore -> Maybe (State r)

Retrieves a State from the StateStore container.

stateSet :: forall f. StateKey f => State f -> StateStore -> StateStore

Inserts a State in the StateStore container.

stateEmpty :: StateStore

A StateStore with no entries.