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# Memoizer
#
# Copyright (c) 2006 Erik Veenstra
#
# See http://javathink.blogspot.com/2008/09/what-is-memoizer-and-why-should-you.html
# Memoizer wraps objects to provide cached method calls.
#
# class X
# def initialize ; @tick = 0 ; end
# def tick; @tick + 1; end
# def memo; @memo ||= Memoizer.new(self) ; end
# end
#
# x = X.new
# x.tick #=> 1
# x.memo.tick #=> 2
# x.tick #=> 3
# x.memo.tick #=> 2
# x.tick #=> 4
# x.memo.tick #=> 2
#
# You can also use to cache collections of objects to gain code speed ups.
#
# points = points.collect{|point| Memoizer.cache(point)}
#
# After our algorithm has finished using points, we want to get rid of
# these Memoizer objects. That's easy:
#
# points = points.collect{|point| point.__self__ }
#
# Or if you prefer (it is ever so slightly safer):
#
# points = points.collect{|point| Memoizer.uncache(point)}
#
class Memoizer
#private :class, :clone, :display, :type, :method, :to_a, :to_s
private *instance_methods(true).select{ |m| m.to_s !~ /^__/ }
def initialize(object)
@self = object
@cache = {}
end
def __self__ ; @self ; end
# Not thread-safe! Speed is important in caches... ;]
def method_missing(method_name, *args, &block)
@cache[[method_name, args, block]] ||= @self.__send__(method_name, *args, &block)
end
#def self; @self; end
def self.cache(object)
new(object)
end
def self.uncache(cached_object)
cached_object.instance_variable_get('@self')
end
end
Version data entries
11 entries across 11 versions & 2 rubygems