package Tree::Simple::Visitor::PathToRoot;
use strict;
use warnings;
our $VERSION = '0.02';
use Scalar::Util qw(blessed);
use base qw(Tree::Simple::Visitor);
sub new {
my ($_class) = @_;
my $class = ref($_class) || $_class;
my $visitor = {};
bless($visitor, $class);
$visitor->_init();
return $visitor;
}
sub visit {
my ($self, $tree) = @_;
(blessed($tree) && $tree->isa("Tree::Simple"))
|| die "Insufficient Arguments : You must supply a valid Tree::Simple object";
# create an array for our path
my @path;
# we need to climb up the tree and
# collect the nodes
my $filter_function = $self->getNodeFilter();
my $current_tree = $tree;
until ($current_tree->isRoot()) {
unshift @path => ($filter_function ?
$filter_function->($current_tree)
:
$current_tree->getNodeValue());
$current_tree = $current_tree->getParent();
}
# now grab the trunk if specified
unshift @path => ($filter_function ?
$filter_function->($current_tree)
:
$current_tree->getNodeValue()) if $self->includeTrunk();
# now store our path in results
$self->setResults(@path);
}
sub getPath {
my ($self) = @_;
return $self->getResults();
}
sub getPathAsString {
my ($self, $delimiter) = @_;
$delimiter ||= ", ";
return join $delimiter => $self->getResults();
}
1;
__END__
=head1 NAME
Tree::Simple::Visitor::PathToRoot - A Visitor for finding the path back a Tree::Simple object's root
=head1 SYNOPSIS
use Tree::Simple::Visitor::PathToRoot;
# create an instance of our visitor
my $visitor = Tree::Simple::Visitor::PathToRoot->new();
# pass the visitor to a Tree::Simple object
$tree->accept($visitor);
# now get the accumulated path as a string
# with the '/' character as the delimiter
print $visitor->getPathAsString("/");
# include the tree's trunk in your
# output as well
$visitor->includeTrunk();
# for more complex node objects, you can specify
# a node filter which will be used to extract the
# information desired from each node
$visitor->setNodeFilter(sub {
my ($t) = @_;
return $t->getNodeValue()->description();
});
# you can also get the path back as an array
my @path = $visitor->getPath();
=head1 DESCRIPTION
Given a Tree::Simple object, this Visitor will find the path back to the tree's root node.
=head1 METHODS
=over 4
=item B<new>
There are no arguments to the constructor the object will be in its default state. You can use the C<includeTrunk> and C<setNodeFilter> methods to customize its behavior.
=item B<includeTrunk ($boolean)>
Based upon the value of C<$boolean>, this will tell the visitor to collect the trunk of the tree as well.
=item B<setNodeFilter ($filter_function)>
This method accepts a CODE reference as its C<$filter_function> argument and throws an exception if it is not a code reference. This code reference is used to filter the tree nodes as they are collected. This can be used to customize output, or to gather specific information from a more complex tree node. The filter function should accept a single argument, which is the current Tree::Simple object.
=item B<visit ($tree)>
This is the method that is used by Tree::Simple's C<accept> method. It can also be used on its own, it requires the C<$tree> argument to be a Tree::Simple object (or derived from a Tree::Simple object), and will throw and exception otherwise.
=item B<getPath>
This will return the collected path as an array, or in scalar context, as an array reference.
=item B<getPathAsString ($delimiter)>
This will return the collected path as a string with the path elements joined by a C<$delimiter>. If no C<$delimiter> is specified, the default (', ') will be used.
=back
=head1 BUGS
None that I am aware of. Of course, if you find a bug, let me know, and I will be sure to fix it.
=head1 CODE COVERAGE
See the B<CODE COVERAGE> section in L<Tree::Simple::VisitorFactory> for more inforamtion.
=head1 SEE ALSO
These Visitor classes are all subclasses of B<Tree::Simple::Visitor>, which can be found in the B<Tree::Simple> module, you should refer to that module for more information.
=head1 AUTHOR
stevan little, E<lt>stevan@iinteractive.comE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2004, 2005 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut