GenericTree.php

<?php

class GenericTree {

	public $root;

	function __construct() {
		$this->root = new Node();
	}

	public function insert(Array $indexes, $value) {
		$newNode = new Node($value);
		$currentNode = $this->root;
		$this->_insert($currentNode, $newNode, $indexes);
	}

	private function _insert(Node $currentNode, Node $newNode, Array $indexes) {
		if (sizeof($indexes) > 0) {
			if ($currentNode->getSizeOfChildren() === 0) {
				throw new Exception('insert failed, $indexes level out of bounds');
			}
			$index = array_shift($indexes);
			$currentNode = $currentNode->getChild($index);
			$this->_insert($currentNode, $newNode, $indexes);
		} else {
			$currentNode->addChild($newNode);
		}
	}

	public function inOrder(Callable $preOp, Callable $inOp, Callable $postOp) {
		$this->_inOrder($this->root, $preOp, $inOp, $postOp);
	}

	private function _inOrder(Node $n, Callable $preOp, Callable $inOp, Callable $postOp) {
		try {
			$preOp();
			for($index = 0; $index < $n->getSizeOfChildren(); $index ++) {
				$nodeValue = $n->getChild($index)->value;
				$inOp($nodeValue);
				$this->_inOrder($n->getChild($index), $preOp, $inOp, $postOp);
			}
			$postOp();
		} catch ( Exception $e ) {
			$msg = $e->message();
			throw new Exception("inOrder failed \n $msg");
		}
	}
}

class Node {

	private $children = array ();

	public $value = NULL;

	function __construct($value = NULL) {
		$this->value = $value;
	}

	public function getSizeOfChildren() {
		return sizeof($this->children);
	}

	public function getChild($index) {
		if ($index < sizeof($this->children)) {
			return $this->children [$index];
		} else {
			throw new Exception('getChild failed, $index out of Bounds');
		}
	}

	public function setChild($index, $value) {
		if ($index < sizeof($this->children)) {
			$this->children [$index] = $value;
		} else {
			throw new Exception('setChild failed, $index out of Bounds');
		}
	}

	public function addChild($value) {
		$this->children [] = $value;
	}
}

class GenericTreeTest {

	public function StartTest() {
		echo "Starting Test. <br>";
		$preOp = function () {
			echo "( ";
		};
		$inOp = function ($arg) {
			echo " $arg ";
		};
		$postOp = function (){
			echo " )";
		};
		$tree = new GenericTree();
		$tree->insert(array (), "1");
		$tree->insert(array (), "2");
		$tree->insert(array (), "3");
		$tree->insert(array (), "4");
		$tree->insert(array (3), "4,1");
		$tree->insert(array (3), "4,2");
		$tree->insert(array (2), "3,1");
		$tree->insert(array (2,0), "3,1,1");
		echo $tree->inOrder($preOp, $inOp, $postOp);
		//prints ( 1 ( ) 2 ( ) 3 ( 3,1 ( 3,1,1 ( ) ) ) 4 ( 4,1 ( ) 4,2 ( ) ) )
		echo "<br> Ending Test.";
	}
}

$gt = new GenericTreeTest();
$gt->startTest();