NAME

       Tree::Simple::Visitor::FromNestedHash - A Visitor for creating Tree::Simple objects from nested hash
       trees.

SYNOPSIS

         use Tree::Simple::Visitor::FromNestedHash;

         my $visitor = Tree::Simple::Visitor::FromNestedHash->new();

         # given this nested hash tree
         my $hash_tree = {
                       Root => {
                               Child1 => {
                                       GrandChild1 => {},
                                       GrandChild2 => {}
                                       },
                               Child2 => {}
                               }
                       };

         # set the array tree we
         # are going to convert
         $visitor->setHashTree($hash_tree);

         $tree->accept($visitor);

         # this then creates the equivalent Tree::Simple object:
         # Tree::Simple->new("Root")
         #     ->addChildren(
         #         Tree::Simple->new("Child1")
         #             ->addChildren(
         #                 Tree::Simple->new("GrandChild1"),
         #                 Tree::Simple->new("GrandChild2")
         #             ),
         #         Tree::Simple->new("Child2"),
         #     );

DESCRIPTION

       Given a tree constructed from nested hashes, this Visitor will create the equivalent Tree::Simple
       hierarchy.

METHODS

       new There are no arguments to the constructor the object will be in its default state. You can use the
           "setNodeFilter" methods to customize its behavior.

       setNodeFilter ($filter_function)
           This method accepts a CODE reference as its $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 $filter_function is passed the node value extracted from the hash prior to it being inserted into
           the tree being built. The $filter_function is expected to return the value desired for inclusion into
           the tree.

       setHashTree ($hash_tree)
           This method is used to set the $hash_tree that our Tree::Simple hierarchy will be constructed from.
           It must be in the following form:

             {
               Root => {
                     Child1 => {
                             GrandChild1 => {},
                             GrandChild2 => {}
                             },
                     Child2 => {}
                     }
             }

           Basically each key in the hash is considered a node, values are ignored unless it is a hash reference
           with at least one key in it, in which case it is interpreted as containing the children of the node
           created from the key.

           The tree is validated prior being accepted, if it fails validation an exception will be thrown. The
           rules are as follows;

           The hash tree must not be empty.
               It makes not sense to create a tree out of nothing, so it is assumed that this is a sign of
               something wrong.

           The hash tree must be a single rooted tree.
               The hash tree should have only one key in it's first level, if it has more than one, then it is
               not a single rooted tree.

           NOTE: Hash keys are sorted ascii-betically before being added to the tree, this results in a somewhat
           more predictable hierarchy.

       visit ($tree)
           This is the method that is used by Tree::Simple's "accept" method. It can also be used on its own, it
           requires the $tree argument to be a Tree::Simple object (or derived from a Tree::Simple object), and
           will throw and exception otherwise.

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.

CODE COVERAGE

       See the CODE COVERAGE section in Tree::Simple::VisitorFactory for more information.

SEE ALSO

       These Visitor classes are all subclasses of Tree::Simple::Visitor, which can be found in the Tree::Simple
       module, you should refer to that module for more information.

AUTHOR

       stevan little, <stevan@iinteractive.com>

COPYRIGHT AND LICENSE

       Copyright 2004, 2005 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.