1package Tree::Simple::Visitor::FromNestedArray; 2 3use strict; 4use warnings; 5 6our $VERSION = '0.16'; 7 8use Scalar::Util qw(blessed); 9 10use base qw(Tree::Simple::Visitor); 11 12sub new { 13 my ($_class) = @_; 14 my $class = ref($_class) || $_class; 15 my $visitor = {}; 16 bless($visitor, $class); 17 $visitor->_init(); 18 return $visitor; 19} 20 21sub _init { 22 my ($self) = @_; 23 $self->{array_tree} = undef; 24 $self->SUPER::_init(); 25} 26 27sub setArrayTree { 28 my ($self, $array_tree) = @_; 29 (defined($array_tree) && ref($array_tree) eq 'ARRAY') 30 || die "Insufficient Arguments : You must supply a valid ARRAY reference"; 31 # validate the tree ... 32 # it must not be empty 33 (scalar @{$array_tree} != 0) 34 || die "Insufficient Arguments : The array tree provided is empty"; 35 # it's first element must not be an array 36 (ref($array_tree->[0]) ne 'ARRAY') 37 || die "Incorrect Object Type : The first value in the array tree is an array reference"; 38 # and it must be a single rooted tree 39 (ref($array_tree->[1]) eq 'ARRAY') 40 || die "Incorrect Object Type : The second value in the array tree must be an array reference" 41 if defined($array_tree->[1]); 42 $self->{array_tree} = $array_tree; 43} 44 45sub visit { 46 my ($self, $tree) = @_; 47 (blessed($tree) && $tree->isa("Tree::Simple")) 48 || die "Insufficient Arguments : You must supply a valid Tree::Simple object"; 49 $self->_buildTree( 50 $tree, 51 # our array tree 52 $self->{array_tree}, 53 # get a node filter if we have one 54 $self->getNodeFilter(), 55 # pass the value of includeTrunk too 56 $self->includeTrunk() 57 ); 58} 59 60sub _buildTree { 61 my ($self, $tree, $array, $node_filter, $include_trunk) = @_; 62 my $i = 0; 63 while ($i < scalar @{$array}) { 64 my $node = $array->[$i]; 65 # check to make sure we have a well formed tree 66 (ref($node) ne 'ARRAY') 67 || die "Incorrect Object Type : The node value should never be an array reference"; 68 # filter the node if necessary 69 $node = $node_filter->($node) if defined($node_filter); 70 # create the new tree 71 my $new_tree; 72 if ($include_trunk) { 73 $tree->setNodeValue($node); 74 $new_tree = $tree; 75 } 76 else { 77 $new_tree = Tree::Simple->new($node); 78 $tree->addChild($new_tree); 79 } 80 # increment the index value 81 $i++; 82 # NOTE: 83 # the value of include trunk is only 84 # passed in the recursion, so that 85 # the trunk/root can be populated, 86 # we have no more need for it after 87 # that time. 88 $self->_buildTree($new_tree, $array->[$i++], $node_filter) 89 if ref($array->[$i]) eq 'ARRAY'; 90 } 91} 92 931; 94 95__END__ 96 97=head1 NAME 98 99Tree::Simple::Visitor::FromNestedArray - A Visitor for creating Tree::Simple objects from nested array trees. 100 101=head1 SYNOPSIS 102 103 use Tree::Simple::Visitor::FromNestedArray; 104 105 my $visitor = Tree::Simple::Visitor::FromNestedArray->new(); 106 107 # given this nested array tree 108 my $array_tree = [ 109 'Root', [ 110 'Child1', [ 111 'GrandChild1', 112 'GrandChild2' 113 ], 114 'Child2' 115 ] 116 ]; 117 # set the array tree we 118 # are going to convert 119 $visitor->setArrayTree($array_tree); 120 121 $tree->accept($visitor); 122 123 # this then creates the equivalent Tree::Simple object: 124 # Tree::Simple->new("Root") 125 # ->addChildren( 126 # Tree::Simple->new("Child1") 127 # ->addChildren( 128 # Tree::Simple->new("GrandChild1"), 129 # Tree::Simple->new("GrandChild2") 130 # ), 131 # Tree::Simple->new("Child2"), 132 # ); 133 134=head1 DESCRIPTION 135 136Given a tree constructed from nested arrays, this Visitor will create the equivalent Tree::Simple hierarchy. 137 138=head1 METHODS 139 140=over 4 141 142=item B<new> 143 144There are no arguments to the constructor the object will be in its default state. You can use the C<setNodeFilter>, C<includTrunk> and C<setArrayTree> methods to customize its behavior. 145 146=item B<includTrunk ($boolean)> 147 148Setting the C<$boolean> value to true (C<1>) will cause the node value of the C<$tree> object passed into C<visit> to be set with the root value found in the C<$array_tree>. Setting it to false (C<0>), or not setting it, will result in the first value in the C<$array_tree> creating a new node level. 149 150=item B<setNodeFilter ($filter_function)> 151 152This method accepts a CODE reference as its C<$filter_function> argument and throws an exception if it is not a code reference. This code reference is used to filter the tree nodes as they are created, the C<$filter_function> is passed the node value extracted from the array prior to it being inserted into the tree being built. The C<$filter_function> is expected to return the value desired for inclusion into the tree. 153 154=item B<setArrayTree ($array_tree)> 155 156This method is used to set the C<$array_tree> that our Tree::Simple hierarchy will be constructed from. It must be in the following form: 157 158 [ 159 'Root', [ 160 'Child1', [ 161 'GrandChild1', 162 'GrandChild2' 163 ], 164 'Child2' 165 ] 166 ] 167 168Basically each element in the array is considered a node, unless it is an array reference, in which case it is interpreted as containing the children of the node created from the previous element in the array. 169 170The tree is validated prior being accepted, if it fails validation an exception will be thrown. The rules are as follows; 171 172=over 4 173 174=item The array tree must not be empty. 175 176It makes not sense to create a tree out of nothing, so it is assumed that this is a sign of something wrong. 177 178=item All nodes of the array tree must not be array references. 179 180The root node is validated against this in this function, but all subsequent nodes are checked as the tree is built. Any nodes found to be array references are rejected and an exception is thrown. If you desire your node values to be array references, you can use the node filtering mechanism to achieve this as the node is filtered I<after> it is validated. 181 182=item The array tree must be a single rooted tree. 183 184If there is a second element in the array tree, it is assumed to be the children of the root, and therefore must be in the form of an array reference. 185 186=back 187 188=item B<visit ($tree)> 189 190This is the method that is used by the Tree::Simple C<accept> method. It can also be used on its 191own, it requires the C<$tree> argument to be a Tree::Simple object (or derived from a 192Tree::Simple object), and will throw and exception otherwise. 193 194=back 195 196=head1 BUGS 197 198None that I am aware of. Of course, if you find a bug, let me know, and I will be sure to fix it. 199 200=head1 CODE COVERAGE 201 202See the B<CODE COVERAGE> section in L<Tree::Simple::VisitorFactory> for more information. 203 204=head1 SEE ALSO 205 206These Visitor classes are all subclasses of B<Tree::Simple::Visitor>, which can be found in the 207B<Tree::Simple> module, you should refer to that module for more information. 208 209=head1 AUTHOR 210 211stevan little, E<lt>stevan@iinteractive.comE<gt> 212 213=head1 COPYRIGHT AND LICENSE 214 215Copyright 2004, 2005 by Infinity Interactive, Inc. 216 217L<http://www.iinteractive.com> 218 219This library is free software; you can redistribute it and/or modify 220it under the same terms as Perl itself. 221 222=cut 223