Refactor Ransack::Adapters from conditionals to classes

README.md

@@ -746,16 +746,10 @@ called on a `ransack` search returns a `Mongoid::Criteria` object:
   @people = @q.result.active.order_by(updated_at: -1).limit(10)
 ```
 
-_NOTE: Ransack currently works with either Active Record or Mongoid, but not
+NOTE: Ransack currently works with either Active Record or Mongoid, but not
 both in the same application. If both are present, Ransack will default to
-Active Record only. Here is the code containing the logic:_
-
-```ruby
-  @current_adapters ||= {
-    :active_record => defined?(::ActiveRecord::Base),
-    :mongoid => defined?(::Mongoid) && !defined?(::ActiveRecord::Base)
-  }
-```
+Active Record only. The logic is contained in
+`Ransack::Adapters#instantiate_object_mapper` should you need to override it.
 
 ## Semantic Versioning
 

lib/ransack.rb

@@ -2,7 +2,7 @@ require 'active_support/core_ext'
 require 'ransack/configuration'
 require 'ransack/adapters'
 
-Ransack::Adapters.require_constants
+Ransack::Adapters.object_mapper.require_constants
 
 module Ransack
   extend Configuration
@@ -31,6 +31,6 @@ require 'ransack/helpers'
 require 'action_controller'
 require 'ransack/translate'
 
-Ransack::Adapters.require_adapter
+Ransack::Adapters.object_mapper.require_adapter
 
 ActionController::Base.helper Ransack::Helpers::FormHelper

lib/ransack/adapters.rb

@@ -1,63 +1,60 @@
 module Ransack
   module Adapters
 
-    # TODO: Refactor to remove conditionals
-
-    def self.current_adapters
-      @current_adapters ||= {
-        :active_record => defined?(::ActiveRecord::Base),
-        :mongoid => defined?(::Mongoid) && !defined?(::ActiveRecord::Base)
-      }
+    def self.object_mapper
+      @object_mapper ||= instantiate_object_mapper
     end
 
-    def self.require_constants
-      if current_adapters[:mongoid]
-        require 'ransack/adapters/mongoid/ransack/constants'
+    def self.instantiate_object_mapper
+      if defined?(::ActiveRecord::Base)
+        ActiveRecordAdapter.new
+      elsif defined?(::Mongoid)
+        MongoidAdapter.new
       end
+    end
 
-      if current_adapters[:active_record]
+    class ActiveRecordAdapter
+      def require_constants
         require 'ransack/adapters/active_record/ransack/constants'
       end
-    end
 
-    def self.require_adapter
-      if current_adapters[:active_record]
+      def require_adapter
         require 'ransack/adapters/active_record/ransack/translate'
         require 'ransack/adapters/active_record'
       end
 
-      if current_adapters[:mongoid]
-        require 'ransack/adapters/mongoid/ransack/translate'
-        require 'ransack/adapters/mongoid'
-      end
-    end
-
-    def self.require_context
-      if current_adapters[:active_record]
+      def require_context
         require 'ransack/adapters/active_record/ransack/visitor'
       end
 
-      if current_adapters[:mongoid]
-        require 'ransack/adapters/mongoid/ransack/visitor'
-      end
-    end
-
-    def self.require_nodes
-      if current_adapters[:active_record]
+      def require_nodes
         require 'ransack/adapters/active_record/ransack/nodes/condition'
       end
 
-      if current_adapters[:mongoid]
-        require 'ransack/adapters/mongoid/ransack/nodes/condition'
+      def require_search
+        require 'ransack/adapters/active_record/ransack/context'
       end
     end
 
-    def self.require_search
-      if current_adapters[:active_record]
-        require 'ransack/adapters/active_record/ransack/context'
+    class MongoidAdapter
+      def require_constants
+        require 'ransack/adapters/mongoid/ransack/constants'
       end
 
-      if current_adapters[:mongoid]
+      def require_adapter
+        require 'ransack/adapters/mongoid/ransack/translate'
+        require 'ransack/adapters/mongoid'
+      end
+
+      def require_context
+        require 'ransack/adapters/mongoid/ransack/visitor'
+      end
+
+      def require_nodes
+        require 'ransack/adapters/mongoid/ransack/nodes/condition'
+      end
+
+      def require_search
         require 'ransack/adapters/mongoid/ransack/context'
       end
     end

lib/ransack/context.rb

@@ -1,5 +1,5 @@
 require 'ransack/visitor'
-Ransack::Adapters.require_context
+Ransack::Adapters.object_mapper.require_context
 
 module Ransack
   class Context

lib/ransack/nodes.rb

@@ -3,6 +3,6 @@ require 'ransack/nodes/node'
 require 'ransack/nodes/attribute'
 require 'ransack/nodes/value'
 require 'ransack/nodes/condition'
-Ransack::Adapters.require_nodes
+Ransack::Adapters.object_mapper.require_nodes
 require 'ransack/nodes/sort'
 require 'ransack/nodes/grouping'