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RSAVAGE / Tree-Simple-VisitorFactory-0.16 / lib / Tree / Simple / Visitor / ToNestedHash.pm 

            

              
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package Tree::Simple::Visitor::ToNestedHash;
use strict;
use warnings;
our $VERSION = '0.16';
use Scalar::Util qw(blessed);
use base qw(Tree::Simple::Visitor);
sub new {
    my ($_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";
    # grab our filter (if we have one)
    my $filter = $self->getNodeFilter();
    my %results;
    # get the array
    $self->_buildHash($tree, \%results, $filter);
    # add the trunk if we need to
    %results = (
            ((defined($filter)) ?
                    $filter->($tree)
                    :
                    $tree->getNodeValue()) => { %results }
        ) if $self->includeTrunk();
    # set results
    $self->setResults(\%results);
}
sub _buildHash {
    my ($self, $tree, $accumulator, $filter) = @_;
    foreach my $child ($tree->getAllChildren()) {
        my $node_value = {};
        my $node_key = (defined($filter) ? $filter->($child) : $child->getNodeValue());
        $self->_buildHash($child, $node_value, $filter) unless $child->isLeaf();
        $accumulator->{$node_key} = $node_value;
    }
    return $accumulator;
}
1;
__END__
=head1 NAME
Tree::Simple::Visitor::ToNestedHash - A Visitor for creating nested hash trees from Tree::Simple objects.
=head1 SYNOPSIS
  use Tree::Simple::Visitor::ToNestedHash;
  my $visitor = Tree::Simple::Visitor::ToNestedHash->new();
  # given this Tree::Simple tree
  my $tree = Tree::Simple->new("Root")
                ->addChildren(
                    Tree::Simple->new("Child1")
                        ->addChildren(
                            Tree::Simple->new("GrandChild1"),
                            Tree::Simple->new("GrandChild2")
                        ),
                    Tree::Simple->new("Child2"),
                );
  $tree->accept($visitor);
  my $array_tree = $visitor->getResults();
  # this then creates the equivalent nested array tree:
  # {
  # Root => {
  #         Child1 => {
  #                 GrandChild1 => {},
  #                 GrandChild2 => {}
  #                 },
  #         Child2 => {}
  #         }
  # }
=head1 DESCRIPTION
Given a tree constructed from a Tree::Simple hierarchy, this Visitor will create the equivalent tree of nested hashes.
=head1 METHODS
=over 4
=item B<new>
There are no arguments to the constructor the object will be in its default state. You can use the C<setNodeFilter> and C<includTrunk> methods to customize its behavior.
=item B<includTrunk ($boolean)>
Setting the C<$boolean> value to true (C<1>) will cause the node value of the tree's root to be included in the nested hash output, setting it to false will do the opposite.
=item B<setNodeFilter ($filter_function)>
This method accepts a CODE reference as its C<$filter_function> argument and throws an exception if it is not a code reference. This code reference is used to filter the tree nodes as they are placed into the hash tree. The C<$filter_function> is passed a Tree::Simple object, and is expected to return the value desired for inclusion into the hash tree.
=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<getResults>
This method will return the hash tree constructed.
=back
=head1 Repository
L<https://github.com/ronsavage/Tree-Simple-VisitorFactory>
=head1 SUPPORT
Bugs should be reported via the CPAN bug tracker at
L<https://github.com/ronsavage/Tree-Simple-VisitorFactory/issues>
=head1 CODE COVERAGE
See the B<CODE COVERAGE> section in L<Tree::Simple::VisitorFactory> for more information.
=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