1 2package Tree::Simple::Visitor::Sort; 3 4use strict; 5use warnings; 6 7our $VERSION = '0.03'; 8 9use Scalar::Util qw(blessed); 10 11use base qw(Tree::Simple::Visitor); 12 13sub new { 14 my ($_class) = @_; 15 my $class = ref($_class) || $_class; 16 my $visitor = {}; 17 bless($visitor, $class); 18 $visitor->_init(); 19 return $visitor; 20} 21 22sub _init { 23 my ($self) = @_; 24 $self->{sort_function} = undef; 25 $self->SUPER::_init(); 26} 27 28sub REVERSE { sub ($$) { $_[1]->getNodeValue() cmp $_[0]->getNodeValue() }}; 29sub NUMERIC { sub ($$) { $_[0]->getNodeValue() <=> $_[1]->getNodeValue() }}; 30sub REVERSE_NUMERIC { sub ($$) { $_[1]->getNodeValue() <=> $_[0]->getNodeValue() }}; 31sub ALPHABETICAL { sub ($$) { lc($_[0]->getNodeValue()) cmp lc($_[1]->getNodeValue()) }}; 32sub REVERSE_ALPHABETICAL { sub ($$) { lc($_[1]->getNodeValue()) cmp lc($_[0]->getNodeValue()) }}; 33 34sub setSortFunction { 35 my ($self, $sort_function) = @_; 36 (defined($sort_function) && ref($sort_function) eq "CODE") 37 || die "Insufficient Arguments : You must supply a CODE reference for the sort function"; 38 $self->{sort_function} = $sort_function; 39} 40 41sub visit { 42 my ($self, $tree) = @_; 43 (blessed($tree) && $tree->isa("Tree::Simple")) 44 || die "Insufficient Arguments : You must supply a valid Tree::Simple object"; 45 46 # No childs, nothing to sort 47 return if $tree->isLeaf(); 48 49 my $sort_function; 50 if ($self->{sort_function}) { 51 $sort_function = $self->{sort_function}; 52 } 53 else { 54 # get the node filter 55 my $filter_func = $self->getNodeFilter(); 56 if ($filter_func) { 57 $sort_function = sub { $filter_func->($a) cmp $filter_func->($b) }; 58 } 59 else { 60 $sort_function = sub { $a->getNodeValue() cmp $b->getNodeValue() }; 61 } 62 } 63 64 # otherwise sort them 65 $self->_sortTree($sort_function, $tree); 66} 67 68sub _sortTree { 69 my ($self, $sort_function, $tree) = @_; 70 71 # sort children, using the sort filter 72 my @childs = sort { $sort_function->($a, $b) } $tree->getAllChildren(); 73 74 # Create the new sequence 75 foreach my $child (@childs) { 76 # get the removed child 77 $child = $tree->removeChild($child); 78 # and be sure that is the one 79 # we re-insert 80 $tree->addChild($child); 81 # only sort the child if 82 # it is not a leaf 83 $self->_sortTree($sort_function, $child) unless $child->isLeaf(); 84 } 85} 86 871; 88 89__END__ 90 91=head1 NAME 92 93Tree::Simple::Visitor::Sort - A Visitor for sorting a Tree::Simple object heirarchy 94 95=head1 SYNOPSIS 96 97 use Tree::Simple::Visitor::Sort; 98 99 # create a visitor object 100 my $visitor = Tree::Simple::Visitor::Sort->new(); 101 102 $tree->accept($visitor); 103 # the tree is now sorted ascii-betically 104 105 # set the sort function to 106 # use a numeric comparison 107 $visitor->setSortFunction($visitor->NUMERIC); 108 109 $tree->accept($visitor); 110 # the tree is now sorted numerically 111 112 # set a custom sort function 113 $visitor->setSortFunction(sub { 114 my ($left, $right) = @_; 115 lc($left->getNodeValue()->{name}) cmp lc($right->getNodeValue()->{name}); 116 }); 117 118 $tree->accept($visitor); 119 # the tree's node are now sorted appropriately 120 121=head1 DESCRIPTION 122 123This implements a recursive multi-level sort of a Tree::Simple heirarchy. I think this deserves some more explaination, and the best way to do that is visually. 124 125Given the tree: 126 127 1 128 1.3 129 1.2 130 1.2.2 131 1.2.1 132 1.1 133 4 134 4.1 135 2 136 2.1 137 3 138 3.3 139 3.2 140 3.1 141 142A normal sort would produce the following tree: 143 144 1 145 1.1 146 1.2 147 1.2.1 148 1.2.2 149 1.3 150 2 151 2.1 152 3 153 3.1 154 3.2 155 3.3 156 4 157 4.1 158 159A sort using the built-in REVERSE sort function would produce the following tree: 160 161 4 162 4.1 163 3 164 3.3 165 3.2 166 3.1 167 2 168 2.1 169 1 170 1.3 171 1.2 172 1.2.2 173 1.2.1 174 1.1 175 176As you can see, no node is moved up or down from it's current depth, but sorted with it's siblings. Flexible customized sorting is possible within this framework, however, this cannot be used for tree-balancing or anything as complex as that. 177 178=head1 METHODS 179 180=over 4 181 182=item B<new> 183 184There are no arguments to the constructor the object will be in its default state. You can use the C<setNodeFilter> and C<setSortFunction> methods to customize its behavior. 185 186=item B<includeTrunk ($boolean)> 187 188Based upon the value of C<$boolean>, this will tell the visitor to include the trunk of the tree in the sort as well. 189 190=item B<setNodeFilter ($filter_function)> 191 192This method accepts a CODE reference as it's C<$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 sorted. This can be used 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. 193 194=item B<setSortFunction ($sort_function)> 195 196This method accepts a CODE reference as it's C<$sort_function> argument and throws an exception if it is not a code reference. The C<$sort_function> is used by perl's builtin C<sort> routine to sort each level of the tree. The C<$sort_function> is passed two Tree::Simple objects, and must return 1 (greater than), 0 (equal to) or -1 (less than). The sort function will override and bypass any node filters which have been applied (see C<setNodeFilter> method above), they cannot be used together. 197 198Several pre-built sort functions are provided. All of these functions assume that calling C<getNodeValue> on the Tree::Simple object will return a suitable sortable value. 199 200=over 4 201 202=item REVERSE 203 204This is the reverse of the normal sort using C<cmp>. 205 206=item NUMERIC 207 208This uses the numeric comparison operator C<E<lt>=E<gt>> to sort. 209 210=item REVERSE_NUMERIC 211 212The reverse of the above. 213 214=item ALPHABETICAL 215 216This lowercases the node value before using C<cmp> to sort. This results in a true alphabetical sorting. 217 218=item REVERSE_ALPHABETICAL 219 220The reverse of the above. 221 222=back 223 224If you need to implement one of these sorting routines, but need special handling of your Tree::Simple objects (such as would be done with a node filter), I suggest you read the source code and copy and modify your own sort routine. If it is requested enough I will provide this feature in future versions, but for now I am not sure there is a large need. 225 226=item B<visit ($tree)> 227 228This is the method that is used by Tree::Simple's C<accept> method. It can also be used on its own, it requires the C<$tree> argument to be a Tree::Simple object (or derived from a Tree::Simple object), and will throw and exception otherwise. 229 230It should be noted that this is a I<destructive> action, since the sort happens I<in place> and does not produce a copy of the tree. 231 232=back 233 234=head1 BUGS 235 236None that I am aware of. Of course, if you find a bug, let me know, and I will be sure to fix it. 237 238=head1 CODE COVERAGE 239 240See the B<CODE COVERAGE> section in L<Tree::Simple::VisitorFactory> for more inforamtion. 241 242=head1 SEE ALSO 243 244These 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. 245 246=head1 ACKNOWLEDGEMENTS 247 248=over 4 249 250=item Thanks to Vitor Mori for the idea and much of the code for this Visitor. 251 252=back 253 254=head1 AUTHORS 255 256Vitor Mori, E<lt>vvvv767@hotmail.comE<gt> 257 258stevan little, E<lt>stevan@iinteractive.comE<gt> 259 260=head1 COPYRIGHT AND LICENSE 261 262Copyright 2004, 2005 by Vitor Mori & Infinity Interactive, Inc. 263 264L<http://www.iinteractive.com> 265 266This library is free software; you can redistribute it and/or modify 267it under the same terms as Perl itself. 268 269=cut 270 271