Shock

<?php
class Elem {
    /**
     * @var int
     */
    private $id;
    /**
     * @var string
     */
    private $data;
    /**
     * @var array
     */
    private $children = array();
    /**
     * @var Elem
     */
    private $parent;

    /**
     * @return int;
     */
    public function getId () {
        return $this->id;
    }

    /**
     * @return string;
     */
    public function getData () {
        return $this->data;
    }

    /**
     * @return array;
     */
    public function getChildren () {
        return $this->children;
    }

    /**
     * @return Elem;
     */
    public function getParent () {
        return $this->parent;
    }

    /**
     * @param int $id
     */
    public function setId ($id) {
        $this->id = $id;
    }

    /**
     * @param string $data
     */
    public function setData ($data) {
        $this->data = $data;
    }

    /**
     * @param Elem $children
     */
    public function addChild (Elem $child) {
        $this->children[] = $child;
    }

    /**
     * @param array $children
     */
    public function setChildren (array $children) {
        $this->children = $children;
    }

    /**
     * @param Elem|null $parent
     */
    public function setParent ($parent) {
        $this->parent = $parent;
    }
}
?>