ama-team / ruby-entity-mapper

            class Denormalizer

              include Mixin::Errors

              # @param [Hash{Class, Array<Symbol>}] method_map

              def initialize(method_map)

                @method_map = method_map

              end

              # @param [Object] source

              # @param [AMA::Entity::Mapper::Type] type

              # @param [AMA::Entity::Mapper::Context] context

              def denormalize(source, type, context)

                return source if type.valid?(source, context)

                find_candidate_methods(source.class).each do |candidate|

                  begin

                    next unless source.respond_to?(candidate)

                    value = source.send(candidate)

                    return value if type.valid?(value, context)

                  rescue StandardError => e

                    message = "Method #{candidate} failed with error when " \

                      "denormalizing #{type.type} out of #{source.class}: " \

                      "#{e.message}"

                    context.logger.warn(message)

                  end

                end

                message = "Can't create #{type} instance from #{source.class}"

                mapping_error(message, context: context)

              end

              private

              def find_candidate_methods(klass)

                chain = []

                cursor = klass

                until cursor.nil?

                  chain.push(cursor)

                  cursor = cursor.superclass

                end

                winner = chain.find do |entry|

                  @method_map.key?(entry)

                end

                winner.nil? ? [] : @method_map[winner]

              end

            end