make sure only one finalizer is defined per thread

lib/tlattr_accessors.rb

@@ -33,11 +33,11 @@ def #{name}
 
         def #{name}=(val)
           #{ivar} = Hash.new #{'{|h, k| h[k] = val}' if first_is_default} unless #{ivar}
-          unless #{ivar}.has_key?(Thread.current)
-            finalize = Thread.current.object_id # required for JRuby compatibility
-            ObjectSpace.define_finalizer(Thread.current, lambda { #{ivar}.delete(finalize) })
+          thread_id = Thread.current.object_id
+          unless #{ivar}.has_key?(thread_id)
+            ObjectSpace.define_finalizer(Thread.current, lambda { #{ivar}.delete(thread_id) })
           end
-          #{ivar}[Thread.current.object_id] = val
+          #{ivar}[thread_id] = val
         end
       }, __FILE__, __LINE__
     end

spec/thread_local_accessors_spec.rb

@@ -60,7 +60,6 @@ def initialize(value)
     x.bar.should == 2
   end
 
-  # This will epically FAIL under JRuby, as JRuby doesn't support finalizers
   it 'should not leak memory' do
     x = Foo.new
     n = 6000
@@ -74,5 +73,15 @@ def initialize(value)
     hash.size.should < (n / 2) # it should be a lot lower than n!
   end
 
+  it 'should define only one finalizer per thread' do
+    ObjectSpace.should_receive(:define_finalizer).exactly(:twice)
+    x = Foo.new
+    2.times do
+      Thread.new do
+        10.times { x.foo = "bar" }
+      end.join
+    end
+  end
+
 end
 

tlattr_accessors.gemspec

@@ -2,7 +2,7 @@
 
 Gem::Specification.new do |s|
   s.name = %q{tlattr_accessors}
-  s.version = "0.0.2"
+  s.version = "0.0.3"
   s.authors = ["Maximilian Sch\303\266fmann"]
   s.date = %q{2009-03-10}
   s.description = "thread-local accessors for your classes"