NAME

Tree::Simple::View - A set of classes for viewing Tree::Simple hierarchies

SYNOPSIS

# create a custom Tree View class
package MyCustomTreeView;

use strict;
use warnings; 

# inherit from this class
our @ISA = qw(Tree::Simple::View);

# define (at a minimum) these methods
sub expandPathSimple { ... }
sub expandPathComplex { ... }

sub expandAllSimple { ... }
sub expandAllComplex { ... }    

1;

DESCRIPTION

This serves as an abstract base class to the Tree::Simple::View::* classes. There are two implementing classes included here; Tree::Simple::View::HTML and Tree::Simple::View::DHTML. Other Tree::Simple::View::* classes are also being planned, see the "TO DO" section for more information.

These modules should be considered stable and ready for production use. We have been using this module in production on a number of sites for several years now without issue.

METHODS

new ($tree, %configuration)

Accepts a $tree argument of a Tree::Simple object (or one derived from Tree::Simple), if $tree is not a Tree::Simple object, and exception is thrown. This $tree object does not need to be a ROOT, you can start at any level of the tree you desire. The options in the %config argument are determined by the implementing subclass, and you should refer to that documentation for details.

getTree

A basic accessor to reach the underlying tree object.

getConfig

A basic accessor to reach the underlying configuration hash.

includeTrunk ($boolean)

This controls the getting and setting (through the optional $boolean argument) of the option to include the tree's trunk in the output. Many times, the trunk is not actually part of the tree, but simply a root from which all the branches spring. However, on occasion, it might be nessecary to view a sub-tree, in which case, the trunk is likely intended to be part of the output. This option defaults to off.

setPathComparisonFunction ($CODE)

This takes a $CODE reference, which can be used to add custom path comparison features to Tree::Simple::View. The function will get two arguments, the first is the $current_path, the second is the $current_tree. When using expandPath, it may sometimes be nessecary to be able to control the comparison of the path values. For instance, your node may be an object and need a specific method called to match the path against.

expandPath (@path)

This method will return a string which will represent your tree expanded along the given @path. This is best shown visually. Given this tree:

Tree-Simple-View
    lib
        Tree
            Simple
                View.pm
                View
                    HTML.pm
                    DHTML.pm
    Makefile.PL
    MANIFEST
    README 
    Changes
    t
        10_Tree_Simple_View_test.t
        20_Tree_Simple_View_HTML_test.t
        30_Tree_Simple_View_DHTML_test.t
        

And given this path:

Tree-Simple-View, lib, Tree, Simple

Your display would like something like this:

Tree-Simple-View
    lib
        Tree
            Simple
                View.pm
                View
    Makefile.PL
    MANIFEST
    README 
    Changes
    t

As you can see, the given path has been expanded, but no other sub-trees are shown. The details of this are subject to the implementating subclass, and their documentation should be consulted.

It should be noted that this method actually calls either the expandPathSimple or expandPathComplex method depending upon the %config argument in the constructor.

expandPathSimple ($tree, @path)

Within this base package, this is an abstract method, it will throw an exception if called.

If no %config argument is given in the constructor, then this method is called by expandPath. This method is optimized since it does not need to process any configuration, but just as the name implies, it's output is simple.

This method can also be used for another purpose, which is to bypass a previously specified configuration and use the base "simple" configuration instead.

expandPathComplex ($tree, $config, @path)

Within this base package, this is an abstract method, it will throw an exception if called.

If a %config argument is given in the constructor, then this method is called by expandPath. This method has been optimized to be used with configurations, and will actually custom compile code (using eval) to speed up the generation of the output.

This method can also be used for another purpose, which is to bypass a previously specified configuration and use the configuration specified (as a HASH reference) in the $config parameter.

expandAll

This method will return a string of HTML which will represent your tree completely expanded. The details of this are subject to the implementating subclass, and their documentation should be consulted.

It should be noted that this method actually calls either the expandAllSimple or expandAllComplex method depending upon the %config argument in the constructor.

expandAllSimple

Within this base package, this is an abstract method, it will throw an exception if called.

If no %config argument is given in the constructor, then this method is called by expandAll. This method too is optimized since it does not need to process any configuration.

This method as well can also be used to bypass a previously specified configuration and use the base "simple" configuration instead.

expandAllComplex ($config)

Within this base package, this is an abstract method, it will throw an exception if called.

If a %config argument is given in the constructor, then this method is called by expandAll. This method too has been optimized to be used with configurations, and will also custom compile code (using eval) to speed up the generation of the output.

Just as with expandPathComplex, this method can be to bypass a previously specified configuration and use the configuration specified (as a HASH reference) in the $config parameter.

DEMO

To view a demo of the Tree::Simple::View::DHTML functionality, look in the examples/ directory.

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.

SEE ALSO

This is just an abstract base class, I suggest you read the documentation in the implementing subclasses:

Tree::Simple::View::HTML

Tree::Simple::View::DHTML

There are a few modules out there that I have seen which do similar things to these modules. I have attempted to describe them here, but not being a user of these modules myself, I can not do them justice. If you think I have mis-represented or just under-represented these modules, please let me know. Also, if I have not included a module which should be here, let me know and I will add it.

Data::TreeDumper

This module is an alternative to Data::Dumper for dumping out any type of data structures. As the author points out, the output of Data::Dumper when dealing with tree structures can be difficult to read at best. This module solves that problem by dumping a much more readable and understandable output specially for tree structures. Data::TreeDumper has many options for output, including custom filters and coloring. I have been working with this module's author and we have been sharing code. Data::TreeDumper can output Tree::Simple objects (http://search.cpan.org/~nkh/Data-TreeDumper-0.15/TreeDumper.pm#Structure_replacement). This gives Tree::Simple the ability to utilize the ASCII/ANSI output styles of Data::TreeDumper. Nadim has used some of the code from Tree::Simple::View to add DHTML output to Data::TreeDumper. The DHTML output can be without tree-lines as for Tree::Simple::View or with tree-lines as with Data::TreeDumper.

HTML::PopupTreeSelect

This module implements a DHTML "pop-up" dialog which contains an expand-collapse tree, which can be used for selecting an item from a hierarchy. It looks to me to be very configurable and have all its bases covered, right down to handling some of the uglies of cross-browser/cross-platform DHTML. However it is really for a very specific purpose, and not for general tree display like this module.

HTML::TreeStructured

This module actually seems to do something very similar to these modules, but to be honest, the documentation is very, very sparse, and so I am not really sure how to go about using it. From a quick read of the code it seems to use HTML::Template as its base, but after that I am not sure.

CGI::Explorer

This module is similar to the HTML::PopupTreeSelect, in that it is intended for a more singular purpose. This module implements a Windows-style explorer tree.

ACKNOWLEDGEMENTS

Thanks to Neyuki for the idea of the setPathComparisonFunction method.

Thanks to Simon Wilcox for the patch and test for XHTML support for Tree::Simple::View::HTML.

AUTHOR

stevan little, <stevan@iinteractive.com>

COPYRIGHT AND LICENSE

Copyright 2004-2008 by Infinity Interactive, Inc.

http://www.iinteractive.com

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.