Helper mixin for retrieving/saving translations for attributes for models

diff --git a/SL/DB/Helper/TranslatedAttributes.pm b/SL/DB/Helper/TranslatedAttributes.pm
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+++ b/SL/DB/Helper/TranslatedAttributes.pm
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+package SL::DB::Helper::TranslatedAttributes;
+
+use strict;
+
+use SL::DB::GenericTranslation;
+
+use parent qw(Exporter);
+our @EXPORT = qw(translated_attribute save_attribute_translation);
+
+use Carp;
+
+sub translated_attribute {
+  my ($self, $attribute, $language_id, %params) = @_;
+
+  $language_id      = _check($self, $attribute, $language_id);
+  my $translation   = _find_translation($self, $attribute, $language_id, 0);
+  $translation    ||= _find_translation($self, $attribute, undef,        0);
+
+  return $translation ? $translation->translation : $self->$attribute;
+}
+
+sub save_attribute_translation {
+  my ($self, $attribute, $language_id, $value) = @_;
+
+  $language_id = _check($self, $attribute, $language_id);
+
+  return _find_translation($self, $attribute, $language_id, 1)->update_attributes(translation => $value);
+}
+
+sub _check {
+  my ($self, $attribute, $language_id) = @_;
+
+  croak "Invalid attribute '${attribute}'" unless $self->can($attribute);
+  croak "Object has not been saved yet"    unless $self->id;
+
+  return ref($language_id) eq 'SL::DB::Language' ? $language_id->id : $language_id;
+}
+
+sub _find_translation {
+  my ($self, $attribute, $language_id, $new_if_not_found) = @_;
+
+  my %params = (language_id      => $language_id,
+                translation_type => ref($self). '/' . $attribute,
+                translation_id   => $self->id);
+
+  return SL::DB::Manager::GenericTranslation->find_by(%params) || ($new_if_not_found ? SL::DB::GenericTranslation->new(%params) : undef);
+}
+
+1;
+
+__END__
+
+=encoding utf8
+
+=head1 NAME
+
+SL::DB::Helper::TranslatedAttributes - Mixin for retrieving and saving
+translations for certain model attributes in the table
+I<generic_translations>
+
+=head1 SYNOPSIS
+
+Declaration:
+
+  package SL::DB::SomeObject;
+  use SL::DB::Helper::Translated;
+
+Usage:
+
+  my $object   = SL::DB::SomeObject->new(id => $::form->{id})->load;
+  my $language = SL::DB::Manager::Language->find_by(description => 'Deutsch');
+  print "Untranslated name: " . $object->name . " translated: " . $object->translated_attribute('name', $language) . "\n";
+
+  print "Now saving new value\n";
+  my $save_ok = $object->save_attribute_translation('name', $language, 'Lieferung frei Haus');
+
+=head1 FUNCTIONS
+
+=over 4
+
+=item C<translated_attribute $attribute, $language_id>
+
+Returns the translation stored for the attribute C<$attribute> and the
+language C<$language_id> (either an ID or an instance of
+L<SL::DB::Language>).
+
+If no translation exists for C<$language_id> or if C<$language_id> is
+undefined then the default translation is looked up.
+
+If neither translation exists then the value of C<< $self->$attribute >>
+is returned.
+
+Requires that C<$self> has a primary ID column named C<id> and that
+the object has been saved.
+
+=item C<save_attribute_translation $attribute, $language_id, $value>
+
+Saves the translation C<$value> for the attribute C<$attribute> and
+the language C<$language_id> (either an ID or an instance of
+L<SL::DB::Language>).
+
+If C<$language_id> is undefined then the default translation will be
+saved.
+
+Requires that C<$self> has a primary ID column named C<id> and that
+the object has been saved.
+
+Returns the same value as C<save>.
+
+=back
+
+=head1 EXPORTS
+
+This mixin exports the functions L</translated_attribute> and
+L</save_attribute_translation>.
+
+=head1 BUGS
+
+Nothing here yet.
+
+=head1 AUTHOR
+
+Moritz Bunkus E<lt>m.bunkus@linet-services.deE<gt>
+
+=cut