Class: Ref::SoftValueMap

Inherits:
AbstractReferenceValueMap show all
Defined in:
lib/ref/soft_value_map.rb

Overview

Implementation of a map in which soft references are kept to the map values. This allows the garbage collector to reclaim these objects if the only reference to them is the soft reference in the map.

This is often useful for cache implementations since the map can be allowed to grow without bound and the garbage collector can be relied on to clean it up as necessary. One must be careful, though, when accessing entries since the values can be collected at any time until there is a strong reference to them.

Example usage:

cache = Ref::SoftValueMap.new
foo = "foo"
cache["strong"] = foo  # add a value with a strong reference
cache["soft"] = "bar"  # add a value without a strong reference
cache["strong"]        # "foo"
cache["soft"]          # "bar"
ObjectSpace.garbage_collect
ObjectSpace.garbage_collect
cache["strong"]        # "foo"
cache["soft"]          # nil

See AbstractReferenceValueMap for details.

Method Summary

Methods inherited from AbstractReferenceValueMap

#[], #[]=, #clear, #delete, #each, #initialize, #inspect, #merge!, reference_class, reference_class=, #to_a, #values

Constructor Details

This class inherits a constructor from Ref::AbstractReferenceValueMap