Exceptional Events

exceptionalEvents.php

<?php

class User {
    private $beers = 0;
    public $id;

    /**
     * User constructor.
     */
    public function __construct($id) {
        $this->id = $id;
    }

    public function drinkBeer()
    {
        $this->beers++;

        if($this->beers == 1) {
            throw ExceptionalEventSystemCoded::by($this->id);
        }
        elseif($this->beers > 1) {
            throw TooMuchBeerWasDrunk::by($this->id);
        }
    }
}

class UserRepo {
    private $users = [];

    public function getById($id)
    {
        return $this->users[$id];
    }

    public function add(User $user) {
        $this->users[$user->id] = $user;
    }
}

class BeerDrunk extends Exception {

    public $user;

    public static function by($user)
    {
        $event = new self(sprintf('A beer was drunk by user %s', $user));
        $event->user = $user;

        return $event;
    }
}

class ExceptionalEventSystemCoded extends Exception {

    public $user;

    public static function by($user)
    {
        $event = new self(sprintf('An exceptional event system was coded by user %s', $user));
        $event->user = $user;

        return $event;
    }
}

class TooMuchBeerWasDrunk extends Exception {
    public $user;

    public static function by($user)
    {
        $event = new self(sprintf('Too much beer was drunk by user %s', $user));
        $event->user = $user;

        return $event;
    }
}

class SomeoneFeltAsleep extends Exception {
    public $user;

    public static function thatSomeoneIs($user)
    {
        $event = new self(sprintf('User %s felt asleep', $user));
        $event->user = $user;

        return $event;
    }
}


$userRepo = new UserRepo();
$user1 = new User(1);
$userRepo->add($user1);

$handlers = [
    BeerDrunk::class => function(BeerDrunk $beerDrunk) use($userRepo) {
        $user = $userRepo->getById($beerDrunk->user);
        $user->drinkBeer();
    },
    ExceptionalEventSystemCoded::class => function(ExceptionalEventSystemCoded $systemCoded) use($userRepo) {
        $user = $userRepo->getById($systemCoded->user);
        $user->drinkBeer();
    },
    TooMuchBeerWasDrunk::class => function(TooMuchBeerWasDrunk $tooMuchBeerWasDrunk) {
        throw SomeoneFeltAsleep::thatSomeoneIs($tooMuchBeerWasDrunk->user);
    }
];

$param = null;
$handler = function($param) {
  throw BeerDrunk::by(1);
};

do {
    $eventCatched = false;
    try {
        $handler($param);
    }
    catch(Exception $e) {
        $eventCatched = true;
        echo $e->getMessage() . PHP_EOL;

        $handler = isset($handlers[get_class($e)]) ? $handlers[get_class($e)] : null;
        $param = $e;
    }
} while($handler && $eventCatched);

// A beer was drunk by user 1
// An exceptional event system was coded by user 1
// A beer was drunk by user 1
// Too much beer was drunk by user 1
// User 1 felt asleep