package Tree::Simple::VisitorFactory; use strict; use warnings; our $VERSION = '0.10'; sub new { my ($class) = @_; return bless \$class; } sub get { my ($class, $visitor) = @_; (defined($visitor)) || die "Insufficient Arguments : You must specify a Visitor to load"; $visitor = "Tree::Simple::Visitor::$visitor"; eval "require $visitor"; die "Illegal Operation : Could not load Visitor ($visitor) because $@" if $@; return $visitor->new(); } *getVisitor = \&get; 1; __END__ =head1 NAME Tree::Simple::VisitorFactory - A factory object for dispensing Visitor objects =head1 SYNOPSIS use Tree::Simple::VisitorFactory; my $tf = Tree::Simple::VisitorFactory->new(); my $visitor = $tf->get("PathToRoot"); # or call it as a class method my $visitor = Tree::Simple::VisitorFactory->getVisitor("PathToRoot"); =head1 DESCRIPTION This object is really just a factory for dispensing Tree::Simple::Visitor::* objects. It is not required to use this package in order to use all the Visitors, it is just a somewhat convienient way to avoid having to type thier long class names. I considered making this a Singleton, but I did not because I thought that some people might not want that. I know that I am very picky about using Singletons, especially in multiprocess environments like mod_perl, so I implemented the smallest instance I knew how to, and made sure all other methods could be called as class methods too. =head1 METHODS =over 4 =item B<new> Returns an minimal instance of this object, basically just a reference back to the package (literally, see the source if you care). =item B<get ($visitor_type)> Attempts to load the C<$visitor_type> and returns an instance of it if successfull. If no C<$visitor_type> is specified an exception is thrown, if C<$visitor_type> fails to load, and exception is thrown. =item B<getVisitor ($visitor_type)> This is an alias of C<get>. =back =head1 AVAILABLE VISITORS This distibution provides a number of Visitor objects which can be loaded just by giving their name. Below is a description of the available Visitors and a sort description of what they do. I have attempted to classify the Visitors into groups which are related to their use. This factory will load any module contained inside the B<Tree::Simple::Visitor::*> namespace. Given a name, it will attempt to C<require> the module B<Tree::Simple::Visitor::E<lt>I<Name>E<gt>.pm>. This allows others to create Visitors which can be accessed with this factory, without needed to include them in this distrobution. =head2 Search/Path Related Visitors =over 4 =item B<PathToRoot> Given a Tree::Simple object, this Visitor will find the path back to the tree's root node. =item B<FindByPath> Given a path and Tree::Simple hierarchy, this Visitor will attempt to find the node specified by the path. =item B<FindByUID> Given a UID and Tree::Simple hierarchy, this Visitor will attempt to find the node with the same UID. =item B<FindByNodeValue> Given a node value and Tree::Simple hierarchy, this Visitor will attempt to find the node with the same node value. =back =head2 Traversal Visitors =over 4 =item B<BreadthFirstTraversal> This implements a breadth-first traversal of a Tree::Simple hierarchy. =item B<PostOrderTraversal> Post-order traversal is a variation of the depth-first traversal in which the sub-tree's are processed I<before> the parent. =item B<PreOrderTraversal> Pre-order traversal is a depth-first traversal method in which the sub-tree's are processed I<after> the parent. =back =head2 FileSystem Visitors =over 4 =item B<LoadDirectoryTree> This visitor can be used to load a directory tree into a Tree::Simple hierarchy. =item B<CreateDirectoryTree> This visitor can be used to create a set of directories and files from a Tree::Simple object hierarchy. =back =head2 Conversion Visitors =over 4 =item B<FromNestedArray> Given a tree constructed from nested arrays, this Visitor will create the equivalent Tree::Simple heirarchy. =item B<ToNestedArray> Given a Tree::Simple heirarchy, this Visitor will create the equivalent tree constructed from nested arrays. =item B<FromNestedHash> Given a tree constructed from nested hashs, this Visitor will create the equivalent Tree::Simple heirarchy. =item B<ToNestedHash> Given a Tree::Simple heirarchy, this Visitor will create the equivalent tree constructed from nested hashes. =back =head2 Reflective Visitors =over 4 =item B<LoadClassHierarchy> Given a class name or instance, this Visitor will create a Tree::Simple hierarchy which models the classes inheritance heirarchy. =back =head2 Misc. Visitors =over 4 =item B<GetAllDescendents> Given a Tree::Simple instance this Visitor will return all the descendents recursively on down the hierarchy. =item B<Sort> This implements a multi-level sort of a Tree::Simple heirarchy. =item B<VariableDepthClone> A Visitor for cloning parts of Tree::Simple hierarchy =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 I use B<Devel::Cover> to test the code coverage of my tests, below is the B<Devel::Cover> report on this module test suite. -------------------------------------------- ------ ------ ------ ------ ------ ------ ------ File stmt branch cond sub pod time total -------------------------------------------- ------ ------ ------ ------ ------ ------ ------ Tree/Simple/VisitorFactory.pm 100.0 100.0 n/a 100.0 100.0 0.4 100.0 Tree/Simple/Visitor/BreadthFirstTraversal.pm 100.0 100.0 66.7 100.0 100.0 2.5 96.3 Tree/Simple/Visitor/PostOrderTraversal.pm 100.0 100.0 77.8 100.0 100.0 1.7 96.3 Tree/Simple/Visitor/PreOrderTraversal.pm 100.0 n/a 33.3 100.0 100.0 0.7 90.5 Tree/Simple/Visitor/CreateDirectoryTree.pm 100.0 85.7 86.7 100.0 100.0 3.4 95.8 Tree/Simple/Visitor/LoadClassHierarchy.pm 100.0 73.1 33.3 100.0 100.0 4.9 89.2 Tree/Simple/Visitor/LoadDirectoryTree.pm 100.0 89.3 85.2 100.0 100.0 26.1 94.7 Tree/Simple/Visitor/FindByNodeValue.pm 100.0 100.0 86.7 100.0 100.0 3.1 98.3 Tree/Simple/Visitor/FindByPath.pm 100.0 100.0 66.7 100.0 100.0 1.2 97.9 Tree/Simple/Visitor/FindByUID.pm 100.0 100.0 86.7 100.0 100.0 2.9 98.3 Tree/Simple/Visitor/GetAllDescendents.pm 100.0 100.0 77.8 100.0 100.0 2.3 97.1 Tree/Simple/Visitor/PathToRoot.pm 100.0 87.5 75.0 100.0 100.0 0.8 95.1 Tree/Simple/Visitor/Sort.pm 100.0 100.0 77.8 100.0 100.0 8.8 98.1 Tree/Simple/Visitor/ToNestedArray.pm 100.0 100.0 66.7 100.0 100.0 1.5 96.5 Tree/Simple/Visitor/ToNestedHash.pm 100.0 100.0 66.7 100.0 100.0 1.4 96.5 Tree/Simple/Visitor/FromNestedArray.pm 100.0 94.4 81.8 100.0 100.0 8.1 96.6 Tree/Simple/Visitor/FromNestedHash.pm 100.0 91.7 77.8 100.0 100.0 4.8 95.9 Tree/Simple/Visitor/VariableDepthClone.pm 100.0 100.0 66.7 100.0 100.0 25.5 97.3 -------------------------------------------- ------ ------ ------ ------ ------ ------ ------ Total 100.0 93.8 76.3 100.0 100.0 100.0 96.1 -------------------------------------------- ------ ------ ------ ------ ------ ------ ------ =head1 SEE ALSO These Visitor classes are meant to work with L<Tree::Simple> hierarchies, 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