1 2package Tree::Simple::Visitor::ToNestedHash; 3 4use strict; 5use warnings; 6 7our $VERSION = '0.02'; 8 9use Scalar::Util qw(blessed); 10 11use base qw(Tree::Simple::Visitor); 12 13sub new { 14 my ($_class) = @_; 15 my $class = ref($_class) || $_class; 16 my $visitor = {}; 17 bless($visitor, $class); 18 $visitor->_init(); 19 return $visitor; 20} 21 22sub visit { 23 my ($self, $tree) = @_; 24 (blessed($tree) && $tree->isa("Tree::Simple")) 25 || die "Insufficient Arguments : You must supply a valid Tree::Simple object"; 26 # grab our filter (if we have one) 27 my $filter = $self->getNodeFilter(); 28 my %results; 29 # get the array 30 $self->_buildHash($tree, \%results, $filter); 31 # add the trunk if we need to 32 %results = ( 33 ((defined($filter)) ? 34 $filter->($tree) 35 : 36 $tree->getNodeValue()) => { %results } 37 ) if $self->includeTrunk(); 38 # set results 39 $self->setResults(\%results); 40} 41 42sub _buildHash { 43 my ($self, $tree, $accumulator, $filter) = @_; 44 foreach my $child ($tree->getAllChildren()) { 45 my $node_value = {}; 46 my $node_key = (defined($filter) ? $filter->($child) : $child->getNodeValue()); 47 $self->_buildHash($child, $node_value, $filter) unless $child->isLeaf(); 48 $accumulator->{$node_key} = $node_value; 49 } 50 return $accumulator; 51} 52 53 541; 55 56__END__ 57 58=head1 NAME 59 60Tree::Simple::Visitor::ToNestedHash - A Visitor for creating nested hash trees from Tree::Simple objects. 61 62=head1 SYNOPSIS 63 64 use Tree::Simple::Visitor::ToNestedHash; 65 66 my $visitor = Tree::Simple::Visitor::ToNestedHash->new(); 67 68 # given this Tree::Simple tree 69 my $tree = Tree::Simple->new("Root") 70 ->addChildren( 71 Tree::Simple->new("Child1") 72 ->addChildren( 73 Tree::Simple->new("GrandChild1"), 74 Tree::Simple->new("GrandChild2") 75 ), 76 Tree::Simple->new("Child2"), 77 ); 78 79 $tree->accept($visitor); 80 81 my $array_tree = $visitor->getResults(); 82 83 # this then creates the equivalent nested array tree: 84 # { 85 # Root => { 86 # Child1 => { 87 # GrandChild1 => {}, 88 # GrandChild2 => {} 89 # }, 90 # Child2 => {} 91 # } 92 # } 93 94=head1 DESCRIPTION 95 96Given a tree constructed from a Tree::Simple heirarchy, this Visitor will create the equivalent tree of nested hashes. 97 98=head1 METHODS 99 100=over 4 101 102=item B<new> 103 104There are no arguments to the constructor the object will be in its default state. You can use the C<setNodeFilter> and C<includTrunk> methods to customize its behavior. 105 106=item B<includTrunk ($boolean)> 107 108Setting the C<$boolean> value to true (C<1>) will cause the node value of the tree's root to be included in the nested hash output, setting it to false will do the opposite. 109 110=item B<setNodeFilter ($filter_function)> 111 112This 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. 113 114=item B<visit ($tree)> 115 116This is the method that is used by Tree::Simple's C<accept> method. It can also be used on its own, it requires the C<$tree> argument to be a Tree::Simple object (or derived from a Tree::Simple object), and will throw and exception otherwise. 117 118=item B<getResults> 119 120This method will return the hash tree constructed. 121 122=back 123 124=head1 BUGS 125 126None that I am aware of. Of course, if you find a bug, let me know, and I will be sure to fix it. 127 128=head1 CODE COVERAGE 129 130See the B<CODE COVERAGE> section in L<Tree::Simple::VisitorFactory> for more inforamtion. 131 132=head1 SEE ALSO 133 134These 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. 135 136=head1 AUTHOR 137 138stevan little, E<lt>stevan@iinteractive.comE<gt> 139 140=head1 COPYRIGHT AND LICENSE 141 142Copyright 2004, 2005 by Infinity Interactive, Inc. 143 144L<http://www.iinteractive.com> 145 146This library is free software; you can redistribute it and/or modify 147it under the same terms as Perl itself. 148 149=cut 150