weakling: a collection of weakref utilities for Ruby

== Summary ==

This library provides:

* a modified WeakRef implementation for JRuby that supports a reference queue
* a WeakRef::RefQueue class
* a weak-valued ID map to replace typical uses of _id2ref

In the future it may provide additional features like a generic WeakHash or other
reference types like soft and phantom references.

The weakling repository is at http://github.com/headius/weakling.

== Usage ==

Just require 'weakling'. It will require 'weakref' along with the refqueue JRuby
extension and the weakling/collections library containing the weak id hash.

== RefQueue Example ==

require 'weakling'
require 'java'

q = WeakRef::RefQueue.new
wr = WeakRef.new(Object.new, q)
puts "weakref object: #wrwr.__id__"

puts "running GC"

puts "weakref alive?: #wrwr.weakref_alive?"
puts "weakref object from queue: #qq.pollq.poll.__id__"

== WeakRef::IdHash Example ==

require 'weakling'

wh = WeakRef::IdHash.new

ary = (1..10).to_a.map Object.new
ids = ary.map {|o| wh.add(o)}

puts "all items in weak_id_hash:"
ids.each {|i| puts "#{i} = #wh[i]"}

puts "dereferencing objects"
ary = nil

puts "forcing GC"
require 'java'

puts "all items in weak id hash:"
ids.each {|i| puts "#{i} = #wh[i]"}