Safe Haskell | None |
---|---|
Language | Haskell2010 |
UnliftIO.MessageBox.Class
Description
This module contains a type class that describes exchangable operations on messages boxes.
Synopsis
- class (IsMessageBox (MessageBox cfg), IsInput (Input (MessageBox cfg))) => IsMessageBoxFactory cfg where
- type MessageBox cfg :: Type -> Type
- getConfiguredMessageLimit :: cfg -> Maybe Int
- newMessageBox :: MonadUnliftIO m => cfg -> m (MessageBox cfg a)
- class IsInput (Input msgBox) => IsMessageBox msgBox where
- type Input msgBox :: Type -> Type
- receive :: MonadUnliftIO m => msgBox a -> m (Maybe a)
- tryReceive :: MonadUnliftIO m => msgBox a -> m (Future a)
- receiveAfter :: MonadUnliftIO m => msgBox a -> Int -> m (Maybe a)
- newInput :: MonadUnliftIO m => msgBox a -> m (Input msgBox a)
- class IsInput input where
- deliver :: MonadUnliftIO m => input a -> a -> m Bool
- handleMessage :: (MonadUnliftIO m, IsMessageBox msgBox) => msgBox message -> (message -> m b) -> m (Maybe b)
Documentation
class (IsMessageBox (MessageBox cfg), IsInput (Input (MessageBox cfg))) => IsMessageBoxFactory cfg where Source #
Create IsMessageBox
instances from a parameter.
Types that determine MessageBox
values.
For a limited message box this might be the limit of the message queue.
Associated Types
type MessageBox cfg :: Type -> Type Source #
Methods
getConfiguredMessageLimit :: cfg -> Maybe Int Source #
Return a message limit.
NOTE: This method was added for unit tests. Although the method is totally valid, it might not be super useful in production code. Also note that the naming follows the rule: Reserve short names for entities that are used often.
newMessageBox :: MonadUnliftIO m => cfg -> m (MessageBox cfg a) Source #
Create a new msgBox
.
This is required to receive a message.
NOTE: Only one process may receive on an msgBox.
Instances
class IsInput (Input msgBox) => IsMessageBox msgBox where Source #
A type class for msgBox types. A common interface for receiving messages.
Minimal complete definition
Methods
receive :: MonadUnliftIO m => msgBox a -> m (Maybe a) Source #
Receive a message. Take whatever time it takes.
Return Just
the value or Nothing
when an error
occurred.
NOTE: Nothing may sporadically be returned, especially when there is a lot of load, so please make sure to build your application in such a way, that it anticipates failure.
tryReceive :: MonadUnliftIO m => msgBox a -> m (Future a) Source #
Return a Future
that can be used to wait for the
arrival of the next message.
NOTE: Each future value represents the next slot in the queue
so one future corresponds to exactly that message (should it arrive)
and if that future value is dropped, that message will be lost!
Arguments
:: MonadUnliftIO m | |
=> msgBox a | Message box |
-> Int | Time in micro seconds to wait until the action is invoked. |
-> m (Maybe a) |
Wait for an incoming message or return Nothing.
The default implementation uses tryReceive
to get a
Future
on which awaitFuture
inside a timeout
is called.
Instances might override this with more performant implementations especially non-blocking Unagi channel based implementation.
NOTE: Nothing may sporadically be returned, especially when there is a lot of load, so please make sure to build your application in such a way, that it anticipates failure.
newInput :: MonadUnliftIO m => msgBox a -> m (Input msgBox a) Source #
Create a new input
that enqueus messages,
which are received by the msgBox
Instances
class IsInput input where Source #
A type class for input types. A common interface for delivering messages.
Methods
deliver :: MonadUnliftIO m => input a -> a -> m Bool Source #
Send a message. Take whatever time it takes. Depending on the implementation, this might be a non-blocking operation. Return if the operation was successful.
NOTE: False
may sporadically be returned, especially
when there is a lot of load, so please make sure to
build your application in such a way, that it
anticipates failure.
Instances
IsInput UnlimitedBoxInput Source # | A blocking instance that invokes |
Defined in UnliftIO.MessageBox.Unlimited Methods deliver :: MonadUnliftIO m => UnlimitedBoxInput a -> a -> m Bool Source # | |
IsInput WaitingInput Source # | |
Defined in UnliftIO.MessageBox.Limited Methods deliver :: MonadUnliftIO m => WaitingInput a -> a -> m Bool Source # | |
IsInput NonBlockingInput Source # | |
Defined in UnliftIO.MessageBox.Limited Methods deliver :: MonadUnliftIO m => NonBlockingInput a -> a -> m Bool Source # | |
IsInput BlockingInput Source # | A blocking instance that invokes |
Defined in UnliftIO.MessageBox.Limited Methods deliver :: MonadUnliftIO m => BlockingInput a -> a -> m Bool Source # | |
IsInput i => IsInput (CatchAllInput i) Source # | |
Defined in UnliftIO.MessageBox.CatchAll Methods deliver :: MonadUnliftIO m => CatchAllInput i a -> a -> m Bool Source # |
handleMessage :: (MonadUnliftIO m, IsMessageBox msgBox) => msgBox message -> (message -> m b) -> m (Maybe b) Source #
Receive a message and apply a function to it.