Class: Higgs::LRUCache

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/higgs/cache.rb

Overview

cache by Least Recently Used strategy

Constant Summary collapse

CVS_ID =

for ident(1)

'$Id: cache.rb 841 2008-12-24 09:23:20Z toki $'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(limit_size = 1000) ⇒ LRUCache

Returns a new instance of LRUCache.



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# File 'lib/higgs/cache.rb', line 23

def initialize(limit_size=1000)
  @limit_size = limit_size
  @count = 0
  @cache = {}
end

Instance Attribute Details

#limit_size ⇒ Object (readonly)

Returns the value of attribute limit_size.



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# File 'lib/higgs/cache.rb', line 29

def limit_size
  @limit_size
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/higgs/cache.rb', line 35

def [](key)
  if (cached_pair = @cache[key]) then
    cached_pair[1] = @count
    @count = @count.succ
    return cached_pair[0]
  end
  nil
end

#[]=(key, value) ⇒ Object 



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# File 'lib/higgs/cache.rb', line 44

def []=(key, value)
  if (cached_pair = @cache[key]) then
    cached_pair[1] = @count
  else
    @cache[key] = [ value, @count ]
  end
  @count = @count.succ
  if (@cache.size > @limit_size) then
    purge_old_cache
  end
  value
end

#delete(key) ⇒ Object 



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# File 'lib/higgs/cache.rb', line 65

def delete(key)
  if (cached_pair = @cache.delete(key)) then
    return cached_pair[0]
  end
  nil
end