query.rb in arqo-0.2.0

- old
+ new
@@ -4,21 +4,48 @@
   # Parent class for query objects
   class Query
     attr_reader :relation
     delegate_missing_to :relation
 
-    def initialize(relation = derived_relation)
+    def initialize(relation = associated_relation)
       @relation = relation.extending(scope_module)
     end
 
     private
 
-    def derived_relation_name
-      self.class.name.sub(/Query$/, '')
-    end
+    # Returns the model to which the query object is associated.
+    # By default it will infer the name from the query object's class
+    # assuming the name is the name of the model with "Query" as the suffix.
+    #
+    # As an example, UserQuery would be associated with the User model and
+    # Blog::PostQuery would be associated with the Blog::Post namespaced model.
+    #
+    # This method can be overridden to bypass this convention and associate
+    # the query object to another relation by returning it.
+    #
+    # ==== Example
+    #     class PostQuery < ARQO::Query
+    #       # ...
+    #
+    #       private
+    #
+    #       def associated_relation
+    #         Blog::Post
+    #       end
+    #     end
+    #
+    # @return [Class, ActiveRecord::Relation]
+    def associated_relation
+      class_name = self.class.name
+      derived_relation_name = class_name.sub(/Query$/, '')
 
-    def derived_relation
-      derived_relation_name.constantize.all if Object.const_defined?(derived_relation_name)
+      unless Object.const_defined?(derived_relation_name)
+        raise NameError, "Could not find model #{derived_relation_name} associated " \
+          "to query #{class_name}.\n Make sure the name is correct or override " \
+          '#associated_relation to provide a custom model'
+      end
+
+      derived_relation_name.constantize.all
     end
 
     def scope_module
       "#{self.class}::Scope".constantize
     end