| Portability | non-portable (uses GHC extensions) |
|---|---|
| Maintainer | lemmih@gmail.com |
| Safe Haskell | None |
Data.Acid.Advanced
Description
Home of the more specialized functions.
- scheduleUpdate :: UpdateEvent event => AcidState (EventState event) -> event -> IO (MVar (EventResult event))
- groupUpdates :: UpdateEvent event => AcidState (EventState event) -> [event] -> IO ()
- update' :: (UpdateEvent event, MonadIO m) => AcidState (EventState event) -> event -> m (EventResult event)
- query' :: (QueryEvent event, MonadIO m) => AcidState (EventState event) -> event -> m (EventResult event)
- class (Typeable ev, SafeCopy ev, Typeable (MethodResult ev), SafeCopy (MethodResult ev)) => Method ev where
- type MethodResult ev
- type MethodState ev
- methodTag :: ev -> Tag
- class SafeCopy st => IsAcidic st where
- acidEvents :: [Event st]
- data Event st where
- UpdateEvent :: UpdateEvent ev => (ev -> Update (EventState ev) (EventResult ev)) -> Event (EventState ev)
- QueryEvent :: QueryEvent ev => (ev -> Query (EventState ev) (EventResult ev)) -> Event (EventState ev)
Documentation
scheduleUpdate :: UpdateEvent event => AcidState (EventState event) -> event -> IO (MVar (EventResult event))Source
Issue an Update event and return immediately. The event is not durable
before the MVar has been filled but the order of events is honored.
The behavior in case of exceptions is exactly the same as for update.
If EventA is scheduled before EventB, EventA will be executed before EventB:
do scheduleUpdate acid EventA scheduleUpdate acid EventB
groupUpdates :: UpdateEvent event => AcidState (EventState event) -> [event] -> IO ()Source
Schedule multiple Update events and wait for them to be durable, but throw away their results. This is useful for importing existing datasets into an AcidState.
update' :: (UpdateEvent event, MonadIO m) => AcidState (EventState event) -> event -> m (EventResult event)Source
Same as update but lifted into any monad capable of doing IO.
query' :: (QueryEvent event, MonadIO m) => AcidState (EventState event) -> event -> m (EventResult event)Source
Same as query but lifted into any monad capable of doing IO.
class (Typeable ev, SafeCopy ev, Typeable (MethodResult ev), SafeCopy (MethodResult ev)) => Method ev whereSource
The basic Method class. Each Method has an indexed result type and a unique tag.
class SafeCopy st => IsAcidic st whereSource
Methods
Arguments
| :: [Event st] | List of events capable of updating or querying the state. |
We distinguish between events that modify the state and those that do not.
UpdateEvents are executed in a MonadState context and have to be serialized to disk before they are considered durable.
QueryEvents are executed in a MonadReader context and obviously do not have to be serialized to disk.
Constructors
| UpdateEvent :: UpdateEvent ev => (ev -> Update (EventState ev) (EventResult ev)) -> Event (EventState ev) | |
| QueryEvent :: QueryEvent ev => (ev -> Query (EventState ev) (EventResult ev)) -> Event (EventState ev) |