Refactor fragment cache methods

Removed extra calls to constantize and DRY'd the code.

CHANGELOG.md

@@ -21,7 +21,7 @@ Features:
 - [#1340](https://github.com/rails-api/active_model_serializers/pull/1340) Add support for resource-level meta. (@beauby)
 
 Fixes:
-- [#1516](https://github.com/rails-api/active_model_serializers/pull/1501) No longer return a nil href when only
+- [#1516](https://github.com/rails-api/active_model_serializers/pull/1516) No longer return a nil href when only
   adding meta to a relationship link. (@groyoh)
 - [#1458](https://github.com/rails-api/active_model_serializers/pull/1458) Preserve the serializer
   type when fragment caching. (@bdmac)
@@ -31,6 +31,7 @@ Fixes:
 - [#1488](https://github.com/rails-api/active_model_serializers/pull/1488) Require ActiveSupport's string inflections (@nate00)
 
 Misc:
+- [#1527](https://github.com/rails-api/active_model_serializers/pull/1527) Refactor fragment cache class. (@groyoh)
 - [#1560](https://github.com/rails-api/active_model_serializers/pull/1560) Update rubocop and address its warnings. (@bf4 @groyoh)
 - [#1545](https://github.com/rails-api/active_model_serializers/pull/1545) Document how to pass arbitrary options to the
   serializer (@CodedBeardedSignedTaylor)

lib/active_model/serializer/adapter/fragment_cache.rb

@@ -0,0 +1,36 @@
+module ActiveModel
+  class Serializer
+    module Adapter
+      class FragmentCache
+        attr_reader :serializer
+
+        def initialize(adapter, serializer, options)
+          @instance_options = options
+          @adapter    = adapter
+          @serializer = serializer
+        end
+
+        # 1. Create a CachedSerializer and NonCachedSerializer from the serializer class
+        # 2. Serialize the above two with the given adapter
+        # 3. Pass their serializations to the adapter +::fragment_cache+
+        def fetch
+
+        end
+
+        protected
+
+        attr_reader :instance_options, :adapter
+
+        private
+
+
+
+
+
+        def to_valid_const_name(name)
+          name.gsub('::', '_')
+        end
+      end
+    end
+  end
+end