[MODEL] Refactored the delegation implementation to Suppport::Forwardable wrapper

Allow future refactoring/re-implementation/customization of forwarding.
See e.g. https://github.com/mongoid/origin/blob/master/lib/origin/forwardable.rb

Author: karmi

elasticsearch-model/lib/elasticsearch/model.rb

@@ -4,6 +4,8 @@
 
 require 'hashie'
 
+require 'elasticsearch/model/support/forwardable'
+
 require 'elasticsearch/model/adapter'
 require 'elasticsearch/model/adapters/default'
 require 'elasticsearch/model/adapters/active_record'

elasticsearch-model/lib/elasticsearch/model/response.rb

@@ -5,9 +5,9 @@ class Response
         attr_reader :klass, :response
 
         include Enumerable
+        extend  Support::Forwardable
 
-        extend  Forwardable
-        def_delegators :results, :each, :empty?, :size, :slice, :[], :to_ary
+        forward :results, :each, :empty?, :size, :slice, :[], :to_ary
 
         def initialize(klass, response)
           @klass    = klass

elasticsearch-model/lib/elasticsearch/model/response/records.rb

@@ -4,8 +4,8 @@ module Response
       class Records
         include Enumerable
 
-        extend  Forwardable
-        def_delegators :records, :each, :empty?, :size, :slice, :[], :to_a, :to_ary
+        extend  Support::Forwardable
+        forward :records, :each, :empty?, :size, :slice, :[], :to_a, :to_ary
 
         include Base
 

elasticsearch-model/lib/elasticsearch/model/response/results.rb

@@ -8,8 +8,8 @@ class Results
 
         include Enumerable
 
-        extend  Forwardable
-        def_delegators :results, :each, :empty?, :size, :slice, :[], :to_a, :to_ary
+        extend  Support::Forwardable
+        forward :results, :each, :empty?, :size, :slice, :[], :to_a, :to_ary
 
         def initialize(klass, response)
           super

elasticsearch-model/lib/elasticsearch/model/support/forwardable.rb

@@ -0,0 +1,35 @@
+module Elasticsearch
+  module Model
+    module Support
+
+      # Lightweight wrapper around "forwardable.rb" interface,
+      # to allow easy delegation implementation changes in the future.
+      #
+      # Cf. https://github.com/mongoid/origin/blob/master/lib/origin/forwardable.rb
+      #
+      module Forwardable
+        def self.extended(base)
+          base.__send__ :extend, ::Forwardable
+        end
+
+        # Forwards specific method(s) to the provided receiver
+        #
+        # @example Forward the `each` method to `results` object
+        #
+        #   MyClass.forward(:results, :each)
+        #
+        # @param [ Symbol ] receiver        The name of the receiver method
+        # @param [ Symbol, Array ] methods  The forwarded methods
+        #
+        # @api private
+        #
+        def forward(receiver, *methods)
+          methods = Array(methods).flatten
+
+          def_delegators receiver, *methods
+
+        end; module_function :forward
+      end
+    end
+  end
+end