package URI::urn::isbn;
require URI::urn;
@ISA=qw(URI::urn);
use strict;
use Business::ISBN ();
sub _isbn {
my $nss = shift;
$nss = $nss->nss if ref($nss);
my $isbn = Business::ISBN->new($nss);
$isbn = undef if $isbn && !$isbn->is_valid;
return $isbn;
}
sub _nss_isbn {
my $self = shift;
my $nss = $self->nss(@_);
my $isbn = _isbn($nss);
$isbn = $isbn->as_string if $isbn;
return($nss, $isbn);
}
sub isbn {
my $self = shift;
my $isbn;
(undef, $isbn) = $self->_nss_isbn(@_);
return $isbn;
}
sub isbn_publisher_code {
my $isbn = shift->_isbn || return undef;
return $isbn->publisher_code;
}
sub isbn_country_code {
my $isbn = shift->_isbn || return undef;
return $isbn->country_code;
}
sub isbn_as_ean {
my $isbn = shift->_isbn || return undef;
return $isbn->as_ean;
}
sub canonical {
my $self = shift;
my($nss, $isbn) = $self->_nss_isbn;
my $new = $self->SUPER::canonical;
return $new unless $nss && $isbn && $nss ne $isbn;
$new = $new->clone if $new == $self;
$new->nss($isbn);
return $new;
}
1;