sub JSON::set_encoding {
  my ($self,$encoding)=@_;

  my $ok = eval {
   $self->can($encoding) or return 0;
   $self->$encoding();
   return 1;
  };

  die("UNKOWN ENCODING $encoding") unless($ok);

  return $self;
}

JSON->new->set_encoding($parameter{json_charset})->encode(\%hash);