class Counter
{

    public $maxCount = 50;

    private $count = 0;


    public function increase()
    {
        if ($this->count === $this->maxCount) {
            throw new \OutOfBoundsException;
        }

        $this->count++;
    }


    public function getCount()
    {
        return $this->count
    }

}




class Increasor implements Runnable
{

    /** @var Counter */
    private $counter;


    public function __construct(Counter $counter)
    {
        $this->counter = $counter;
    }


    public function run()
    {
        while (TRUE) {
            try {
                $this->counter->increase();
            } catch (\utOfBoundsException $e) {
                break;
            }
        }
    }
}


$counter = new Couter();

for ($i=0; $i < 3 ;$i++) {
    new Thread(new Increasor($counter)).start();
}