instantiate

# File activerecord/lib/active_record/associations/join_dependency.rb, line 132
      def instantiate(result_set, aliases)
        primary_key = aliases.column_alias(join_root, join_root.primary_key)
        type_caster = result_set.column_type primary_key

        seen = Hash.new { |h,parent_klass|
          h[parent_klass] = Hash.new { |i,parent_id|
            i[parent_id] = Hash.new { |j,child_klass| j[child_klass] = {} }
          }
        }

        model_cache = Hash.new { |h,klass| h[klass] = {} }
        parents = model_cache[join_root]
        column_aliases = aliases.column_aliases join_root

        result_set.each { |row_hash|
          primary_id = type_caster.type_cast row_hash[primary_key]
          parent = parents[primary_id] ||= join_root.instantiate(row_hash, column_aliases)
          construct(parent, join_root, row_hash, result_set, seen, model_cache, aliases)
        }

        parents.values
      end