LRU.hs

-----------------------------------------------------------------------------
-- |
-- Module      :  Data.Policy.LRU
-- Copyright   :  Peter Robinson 2009
-- License     :  LGPL
--
-- Maintainer  :  Peter Robinson <thaldyron@gmail.com>
-- Stability   :  experimental
-- Portability :  non-portable (requires STM)
--
-- Provides a least recently used caching policy.
-- Note: This module is simply a wrapper around the LRU-package.
-----------------------------------------------------------------------------

module Data.CacheStructure.LRU( L.LRU )
where
import Control.Exception 
import Data.CacheStructure
import qualified Data.LRU as L

instance Ord a => CacheStructure L.LRU a where
  hit          = L.hit
  pop l = case L.last l of
                   Nothing -> throw $ CacheException "Cache structure is empty!"
                   Just a  -> (L.pop l,a)
  last l       = case L.last l of
                   Nothing -> throw $ CacheException "Cache structure is empty!"
                   Just a  -> a
  empty  = L.empty
  null   = L.null
  toList = L.toList
  delete = L.delete
  member = L.member
  size   = L.size