Implement identity map!

lib/twitter/base.rb

@@ -1,8 +1,12 @@
+require 'twitter/identity_map'
+
 module Twitter
   class Base
     attr_accessor :attrs
     alias :to_hash :attrs
 
+    @@identity_map = IdentityMap.new
+
     # Define methods that retrieve the value from an initialized instance variable Hash, using the attribute as a key
     #
     # @overload self.lazy_attr_reader(attr)
@@ -19,12 +23,18 @@ def self.lazy_attr_reader(*attrs)
       end
     end
 
+    def self.new(attrs={})
+      @@identity_map[self.name] ||= {}
+      @@identity_map[self.name][Marshal.dump(attrs)] || super(attrs)
+    end
+
     # Initializes a new Base object
     #
     # @param attrs [Hash]
     # @return [Twitter::Base]
     def initialize(attrs={})
-      @attrs = attrs.dup
+      @attrs = attrs
+      @@identity_map[self.class.name][Marshal.dump(attrs)] = self
     end
 
     # Initializes a new Base object

lib/twitter/identity_map.rb

@@ -0,0 +1,8 @@
+module Twitter
+
+  # Tracks objects to help ensure that each object gets loaded only once.
+  # See: http://www.martinfowler.com/eaaCatalog/identityMap.html
+  class IdentityMap < Hash
+  end
+
+end

spec/twitter/base_spec.rb

@@ -26,4 +26,10 @@
     end
   end
 
+  describe "identical objects" do
+    it "should have the same object_id" do
+      @base.object_id.should == Twitter::Base.new('id' => 1).object_id
+    end
+  end
+
 end