NAME

       Config::Model::BackendTrackOrder - Track read order of elements from configuration

VERSION

       version 2.117

SYNOPSIS

        # inside a backend
        use Config::Model::BackendTrackOrder;

        has tracker => (
           is => 'ro',
           isa => 'Config::Model::BackendTrackOrder',
           lazy_build => 1,
        );

        sub _build_tracker {
           my $self = shift;
           return Config::Model::BackendTrackOrder->new(
               backend_obj => $self,
               node => $self->node,
           ) ;
        }

        # register elements to record user order
        $self->tracker->register_element('foo');
        $self->tracker->register_element('bar');

        # later, when writing data back
        foreach my $elt ( $self->tracker->get_ordered_element_names ) {
             # write data
        }

DESCRIPTION

       This module is used by backends to record the order of the configuration elements found in
       user file. Later these elements can be written back in the file using the same order.

       Data are written in canonical order if "canonical" method of the "Config::Model::Instance"
       in instance returns true.

CONSTRUCTOR

       THe constructor accepts the following parameters:

       backend_obj
           The backend object holding this tracker (required).

       node
           The node holding the backend above

METHODS

   register_element
       Register the element and keep track of the registration order during initial load

       Element registered after initial load (i.e . user modification) are registered using
       canonical order.

   get_ordered_element_names
       Returns a list of elements respecting user's order.

       Returns the canonical list if Instance canonical attribute is 1.

AUTHOR

       Dominique Dumont

COPYRIGHT AND LICENSE

       This software is Copyright (c) 2005-2018 by Dominique Dumont.

       This is free software, licensed under:

         The GNU Lesser General Public License, Version 2.1, February 1999