Fwd: [Haskell-cafe] ANNOUNCE: Data.TCache 0.5.1

29 Oct 2008

      ---------- Forwarded message ----------
From: Alberto G. Corona 
Date: 2008/10/29
Subject: Re: [Haskell-cafe] ANNOUNCE: Data.TCache 0.5.1
To: Joachim Breitner 

I developed it in 2006. At this time I think that Happs did not used STM. I
do not know Happs.State very well. The main difference is that it is far far
simple (only a handfull of methods exported) it is configurable and permit
the full semantic of TVars without loosing content persistence.  Also, the
query is based on let´s say patterns. A pattern is a partilally filled
object. enough to deduce the key. the interface is very natural. For
example:

withResources [ User{ name= "Alberto"} , Product{ id="Playstation"}  buyIt
  where
  buyIt [Just user, Just product]=  [user{due= due user +price product},
product{ stock= stock product -1]]
  buyIt _ = error "either the user or the product not found"

Just prod <- getResource Product{ id="Playstation"}

bla bla bla

2008/10/29 Joachim Breitner 
...
Hi,
Am Dienstag, den 28.10.2008, 23:26 +0100 schrieb Alberto G. Corona :
...
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 TVar updates.
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.
Interesting. Without much deep knowledge, this sounds similar to
HAppS.State. Where are the differences?
Greetings,
Joachim
--
Joachim "nomeata" Breitner
 mail: mail@joachim-breitner.de | ICQ# 74513189 | GPG-Key: 4743206C
 JID: nomeata@joachim-breitner.de | http://www.joachim-breitner.de/
 Debian Developer: nomeata@debian.org
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