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