# $Id: DocumentLocator.pm,v 1.3 2005/10/14 20:31:20 matt Exp $

package XML::SAX::DocumentLocator;

use strict;

sub new {

    my $class = shift;

    my %object;

    tie %object, $class, @_;

    return bless \%object, $class;

}

sub TIEHASH {

    my $class = shift;

    my ($pubmeth, $sysmeth, $linemeth, $colmeth, $encmeth, $xmlvmeth) = @_;

    return bless { 

        pubmeth => $pubmeth,

        sysmeth => $sysmeth,

        linemeth => $linemeth,

        colmeth => $colmeth,

        encmeth => $encmeth,

        xmlvmeth => $xmlvmeth,

    }, $class;

}

sub FETCH {

    my ($self, $key) = @_;

    my $method;

    if ($key eq 'PublicId') {

        $method = $self->{pubmeth};

    }

    elsif ($key eq 'SystemId') {

        $method = $self->{sysmeth};

    }

    elsif ($key eq 'LineNumber') {

        $method = $self->{linemeth};

    }

    elsif ($key eq 'ColumnNumber') {

        $method = $self->{colmeth};

    }

    elsif ($key eq 'Encoding') {

        $method = $self->{encmeth};

    }

    elsif ($key eq 'XMLVersion') {

        $method = $self->{xmlvmeth};

    }

    if ($method) {

        my $value = $method->($key);

        return $value;

    }

    return undef;

}

sub EXISTS {

    my ($self, $key) = @_;

    if ($key =~ /^(PublicId|SystemId|LineNumber|ColumnNumber|Encoding|XMLVersion)$/) {

        return 1;

    }

    return 0;

}

sub STORE {

    my ($self, $key, $value) = @_;

}

sub DELETE {

    my ($self, $key) = @_;

}

sub CLEAR {

    my ($self) = @_;

}

sub FIRSTKEY {

    my ($self) = @_;

    # assignment resets.

    $self->{keys} = {

        PublicId => 1,

        SystemId => 1,

        LineNumber => 1,

        ColumnNumber => 1,

        Encoding => 1,

        XMLVersion => 1,

    };

    return each %{$self->{keys}};

}

sub NEXTKEY {

    my ($self, $lastkey) = @_;

    return each %{$self->{keys}};

}

1;

__END__

=head1 NAME

XML::SAX::DocumentLocator - Helper class for document locators

=head1 SYNOPSIS

  my $locator = XML::SAX::DocumentLocator->new(

      sub { $object->get_public_id },

      sub { $object->get_system_id },

      sub { $reader->current_line },

      sub { $reader->current_column },

      sub { $reader->get_encoding },

      sub { $reader->get_xml_version },

  );

=head1 DESCRIPTION

This module gives you a tied hash reference that calls the

specified closures when asked for PublicId, SystemId,

LineNumber and ColumnNumber.

It is useful for writing SAX Parsers so that you don't have

to constantly update the line numbers in a hash reference on

the object you pass to set_document_locator(). See the source

code for XML::SAX::PurePerl for a usage example.

=head1 API

There is only 1 method: C<new>. Simply pass it a list of

closures that when called will return the PublicId, the

SystemId, the LineNumber, the ColumnNumber, the Encoding 

and the XMLVersion respectively.

The closures are passed a single parameter, the key being

requested. But you're free to ignore that.

=cut