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.