NAME¶
Tree::Simple::Visitor::FromNestedArray - A Visitor for creating Tree::Simple
objects from nested array trees.
SYNOPSIS¶
use Tree::Simple::Visitor::FromNestedArray;
my $visitor = Tree::Simple::Visitor::FromNestedArray->new();
# given this nested array tree
my $array_tree = [
'Root', [
'Child1', [
'GrandChild1',
'GrandChild2'
],
'Child2'
]
];
# set the array tree we
# are going to convert
$visitor->setArrayTree($array_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 arrays, 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",
"includTrunk" and "setArrayTree" methods to customize
its behavior.
- includTrunk ($boolean)
- Setting the $boolean value to true (1) will cause the node value of the
$tree object passed into "visit" to be set with the root value
found in the $array_tree. Setting it to false (0), or not setting it, will
result in the first value in the $array_tree creating a new node
level.
- setNodeFilter ($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 array prior to it being inserted
into the tree being built. The $filter_function is expected to return the
value desired for inclusion into the tree.
- setArrayTree ($array_tree)
- This method is used to set the $array_tree that our Tree::Simple hierarchy
will be constructed from. It must be in the following form:
[
'Root', [
'Child1', [
'GrandChild1',
'GrandChild2'
],
'Child2'
]
]
Basically each element in the array is considered a node, unless it is an
array reference, in which case it is interpreted as containing the
children of the node created from the previous element in the array.
The tree is validated prior being accepted, if it fails validation an
exception will be thrown. The rules are as follows;
- The array tree must not be empty.
- It makes not sense to create a tree out of nothing, so it is assumed that
this is a sign of something wrong.
- All nodes of the array tree must not be array references.
- The root node is validated against this in this function, but all
subsequent nodes are checked as the tree is built. Any nodes found to be
array references are rejected and an exception is thrown. If you desire
your node values to be array references, you can use the node filtering
mechanism to achieve this as the node is filtered after it is
validated.
- The array tree must be a single rooted tree.
- If there is a second element in the array tree, it is assumed to be the
children of the root, and therefore must be in the form of an array
reference.
- visit ($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.