php object pool design pattern

<?php


/**
 * Class Pool
 * @author dılo sürücü <berxudar@gmail.com>
 * example pool design pattern
 */
Class Pool
{


    private $free = [], $occupation = [];


    /**
     * @return mixed|Time
     *
     *
     */
    function get()
    {

        if (count($this->free) == 0) {
            $worker = new Time();
        } else {

            $worker = array_pop($this->free);
        }


        $this->occupation[spl_object_hash($worker)] = $worker;


        return $worker;
    }


    /**
     * @param $worker
     *
     *
     */
    function dispos($worker)
    {

        if (isset($this->occupation[spl_object_hash($worker)])) {

            unset($this->occupation[spl_object_hash($worker)]);

            $this->free[spl_object_hash($worker)] = $worker;
        }

    }


    /**
     * @return int
     *
     */
    function count()
    {

        return count($this->free);
    }

}


/**
 * Class Time
 * 
 * 
 */
class Time
{

    /**
     * @return DateTime
     * 
     */
    function getTime()
    {


        return new DateTime();

    }
}


$pool = new  Pool();

$worker1 = $pool->get();


$worker2 = $pool->get();

$worker3 = $pool->get();

/**
 * 
 * dispos $workers
 */

$pool->dispos($worker1);

$pool->dispos($worker2);


print_r($pool->count());