PHP unlimited classification class

During this time, I was writing a Department permission system and needed to use the unlimited classification technology. I found a lot of code about classification and collected them one by one.
<? Php
/**
* @ Author YangHuan
* @ Datetime
* @ Version 1.0.0
*/

/**
* Short description.
*
* Detail description
* @ Author
* @ Version 1.0
* @ Copyright
* @ Access public
*/
Class Tree
{
/**
* Description
* @ Var
* @ Since 1.0
* @ Access private
*/
Var $ data = array ();

/**
* Description
* @ Var
* @ Since 1.0
* @ Access private
*/
Var $ child = array (-1 => array ());

/**
* Description
* @ Var
* @ Since 1.0
* @ Access private
*/
Var $ layer = array (-1 =>-1 );

/**
* Description
* @ Var
* @ Since 1.0
* @ Access private
*/
Var $ parent = array ();

/**
* Short description.
*
* Detail description
* @ Param none
* @ Global none
* @ Since 1.0
* @ Access private
* @ Return void
* @ Update date time
*/
Function Tree ($ value)
{
$ This-> setNode (0,-1, $ value );
} // End func

/**
* Short description.
*
* Detail description
* @ Param none
* @ Global none
* @ Since 1.0
* @ Access private
* @ Return void
* @ Update date time
*/
Function setNode ($ id, $ parent, $ value)
{
$ Parent = $ parent? $ Parent: 0;

$ This-> data [$ id] = $ value;
$ This-> child [$ id] = array ();
$ This-> child [$ parent] [] = $ id;
$ This-> parent [$ id] = $ parent;

If (! Isset ($ this-> layer [$ parent])
{
$ This-> layer [$ id] = 0;
}
Else
{
$ This-> layer [$ id] = $ this-> layer [$ parent] + 1;
}
} // End func

/**
* Short description.
*
* Detail description
* @ Param none
* @ Global none
* @ Since 1.0
* @ Access private
* @ Return void
* @ Update date time
*/
Function getList (& $ tree, $ root = 0)
{
Foreach ($ this-> child [$ root] as $ key => $ id)
{
$ Tree [] = $ id;

If ($ this-> child [$ id]) $ this-> getList ($ tree, $ id );
}
} // End func

/**
* Short description.
*
* Detail description
* @ Param none
* @ Global none
* @ Since 1.0
* @ Access private
* @ Return void
* @ Update date time
*/
Function getValue ($ id)
{
Return $ this-> data [$ id];
} // End func

/**
* Short description.
*
* Detail description
* @ Param none
* @ Global none
* @ Since 1.0
* @ Access private
* @ Return void
* @ Update date time
*/
Function getLayer ($ id, $ space = false)
{
Return $ space? Str_repeat ($ space, $ this-> layer [$ id]): $ this-> layer [$ id];
} // End func

/**
* Short description.
*
* Detail description
* @ Param none
* @ Global none
* @ Since 1.0
* @ Access private
* @ Return void
* @ Update date time
*/
Function getParent ($ id)
{
Return $ this-> parent [$ id];
} // End func

/**
* Short description.
*
* Detail description
* @ Param none
* @ Global none
* @ Since 1.0
* @ Access private
* @ Return void
* @ Update date time
*/
Function getParents ($ id)
{
While ($ this-> parent [$ id]! =-1)
{
$ Id = $ parent [$ this-> layer [$ id] = $ this-> parent [$ id];
}

Ksort ($ parent );
Reset ($ parent );

Return $ parent;
} // End func

/**
* Short description.
*
* Detail description
* @ Param none
* @ Global none
* @ Since 1.0
* @ Access private
* @ Return void
* @ Update date time
*/
Function getChild ($ id)
{
Return $ this-> child [$ id];
} // End func

/**
* Short description.
*
* Detail description
* @ Param none
* @ Global none
* @ Since 1.0
* @ Access private
* @ Return void
* @ Update date time
*/
Function getChilds ($ id = 0)
{
$ Child = array ($ id );
$ This-> getList ($ child, $ id );

Return $ child;
} // End func
} // End class

?>

--------------------------------------------------------------------------------

Usage

PHP code :--------------------------------------------------------------------------------
// New Tree (root directory name );
// The ID of the root directory is automatically allocated to 0.
$ Tree = new Tree ('root directory ');

// SetNode (directory ID, parent ID, directory name );
$ Tree-> setNode (1, 0, 'Directory 1 ');
$ Tree-> setNode (2, 0, 'Directory 2 ');
$ Tree-> setNode (3, 0, 'Directory 3 ');
$ Tree-> setNode (4, 3, 'Directory 100 ');
$ Tree-> setNode (5, 3, 'Directory 100 ');
$ Tree-> setNode (6, 3, 'Directory 100 ');
$ Tree-> setNode (7, 2, 'Directory 100 ');
$ Tree-> setNode (8, 2, 'Directory 100 ');
$ Tree-> setNode (9, 2, 'Directory 100 ');
$ Tree-> setNode (10, 6, 'Directory 3.3.1 ');
$ Tree-> setNode (11, 6, 'Directory 3.3.2 ');
$ Tree-> setNode (12, 6, 'Directory 3.3.3 ');

// GetChilds (specify the directory ID );
// Obtain the sub-directory of the specified directory. If no sub-directory is specified, it starts from the root directory.
$ Category = $ Tree-> getChilds ();

// Print the output
Foreach ($ category as $ key => $ id)
{
Echo $ Tree-> getLayer ($ id, '|-'). $ Tree-> getValue ($ id). "<br> \ n ";
}