How to give only the player in the event the variable

Ok this title might be slightly wrong but I didn't know what to call this.
Anyways I have this code:

PHP:

    public function onInteract(PlayerInteractEvent $event){
        $player = $event->getPlayer();
        $block = $event->getBlock();
        $level = $this->getServer()->getDefaultLevel();
        $this->mode = 0;
        if($block->getId() == 46) {
            if($this->mode>=0&&$this->mode<=1000) {
                $this->mode++;
                $this->text->setText("§aYour score: §e" . $this->mode . "");
                $level->addParticle($this->text);
                $player->sendPopup("score:" . $this->mode . "");
            }
        }
    }
}

So atm if a player taps TNT(46) it will make $this->mode increase everytime it is tapped. However this is the problem: if a player taps the tnt it will become 1 and then if another player comes along it becomes 2. I want each player to have their own seperate. so what I'm wanting to do is make $this->mode per player.
hope that was understandable

 

I don't quite understand. Is there a plugin which uses this, I need to see a working example