Friday, January 09, 2009
A new version of TCache (0.5.5)
has been uploaded to hackage. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/TCache The main addition of this versión is the capablity to safely handle transact, and serialize to permanent storage many datatypes simultaneously in the same piece of code and incrementally. Just register each new datatype (with registerType ::
). So it is not necessary to glue all types in advance in a single algebraic datatype. I suppose taht "enhanced composablility" applies to this feature.
In this release:
Added a Data.TCache.Dynamic. (SEE dynamicsample.hs)
- Can handle, transact, and serialize to disk many datatypes simultaneously and incrementally
- Dynamic uses the same interface than TCache and add *DResource(s) calls for handling many
- Safe dynamic data handling trough a lighter, indexable and serializable version of Data.Dynamic
- Added KEY object for retrieving any object of any type.
Data.Tcache is a transactional cache with configurable persistence. It tries to simulate Hibernate
for Java or Rails for Ruby. The main difference is that transactions are done in memory trough STM.
There are transactional cache implementations for some J2EE servers like JBOSS.
TCache uses STM. It can atomically apply a function to a list of cached objects. The resulting
objects go back to the cache (withResources). It also can retrieve these objects (getResources).
Persistence can be syncronous (syncCache) or asyncronous, wtih configurable time between cache
writes and configurable cache clearance strategy. the size of the cache can be configured too .
All of this can be done trough clearSyncCacheProc. Even the TVar variables can be accessed
directly (getTVar) to acceess all the semantic of atomic blocks while maintaining the persistence of the
Persistence can be defined for each object: Each object must have a defined key, a default filename
path (if applicable). Persistence is pre-defined in files, but the readResource writeResource and
delResource methods can be redefined to persist in databases or whatever.
There are Samples in the package that explain the main features.