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Tree::Simple::Visitor::FindByUID - A Visitor for finding an element in a Tree::Simple hierarchy by UID


  use Tree::Simple::Visitor::FindByUID;

  # create a visitor object
  my $visitor = Tree::Simple::Visitor::FindByUID->new();

  # set the search path for our tree

  # pass the visitor to a tree

  # fetch the result, which will
  # be the Tree::Simple object that
  # we have found, or undefined
  my $result = $visitor->getResult() || die "No Tree found";


Given a UID and Tree::Simple hierarchy, this Visitor will attempt to find the node with the same UID.



There are no arguments to the constructor the object will be in its default state. You can use the setNodeFilter, setTraversalMethod, includeTrunk and searchForUID methods to customize its behavior.

includeTrunk ($boolean)

Based upon the value of $boolean, this will tell the visitor to include the trunk of the tree in the search as well.

setTraversalMethod ($visitor)

By default we will use Tree::Simple's built in depth-first (pre-order) traverse method. If however, you desire the tree to be search in a different ordering, this can be accomplished using a different traversal method, you can supply a $visitor object implementing that traversal type to this method (See Tree::Simple::Visitor::BreadthFirstTraversal, Tree::Simple::Visitor::PreOrderTraversal and Tree::Simple::Visitor::PostOrderTraversal).

searchForUID ($UID)

This is the UID we will attempt to find within the tree.

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 further check the tree nodes as they are searched and so can be used to customize search behavior. For instance, you could to check against the UID as well as some other criteria. The filter function should accept a single argument, which is the current Tree::Simple object and return either true (1) on success, or false (0) on failure.

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.


This method will return the tree found with the specified UID (set by the searchForUID method) or undef if no tree is found.



Bugs should be reported via the CPAN bug tracker at


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


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.


Thanks to Vitor Mori for the idea for this Visitor.


stevan little, <>


Copyright 2004, 2005 by Infinity Interactive, Inc.

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