What's the best way to cast a custom Class in PHP

casting, class, php, typeof

Solution

Short answer to your question, no you cannot recast an object to another object.

However, Dan Lee's response is a good one and close to what I am suggesting. Why not make the `fillTank` an attribute of a vehicle object, this way all objects extending the vehicle class will know how to fill their own tanks. Something like this:

abstract class Vehicle
{
    protected $tank1;
    protected $tank2;

    // Declaring an abstract function in parent class forces all child class to 
    // implement same class
    abstract public function fillGas() {}
}

class Car extends Vehicle
{
    public function fillGas()
    {
        $this->tank1 = 'full';
    }
}

class SportsCar extends Vehicle
{
    public function fillGas()
    {
        $this->tank1 = 'full';
        $this->tank2 = 'full';
    }
}

class Skateboard extends Vehicle
{
    // Skateboards don't have gastanks, just here to sastify parent abstract definition
    public function fillGas() {}
}

Of course the big fallacy with your OP is that you are assuming that ALL sportscars have two gas tanks, when in fact this not the case. Only certain sportscars have multiple gas tanks.

Another approach is to take a look at `traits` (available as of PHP 5.4). It appears you can enforce interface as well as implementation across objects which do not extend the same class.

-- Update --

Update (Based on responses): In my 'real' case... imagine I have to check various Vehicle types, each with different paint, body, interior, gas_type, cleaner_type, color, etc...

All these attributes you mention are Vehicle attributes, not gastation, fillingstation, parkinglot etc attributes, as such I would add all these attributes to the vehicle class, then you can pass a vehicle to a `GasStation::cleanVehicle()` factory method to manipulate the vehicle attributes.

The code snippet below is DEMONSTRATIVE only, demonstrating how aforementioned attributes should be attached to the vehicle class, and how the `GasStation` class can manipulate vehicle attributes based on the class of vehicle. I wrote the following in 5 minutes, but it's obvious that it will take more thought to properly handle the factory method and whether to pass off to other objects etc. Consider the following:

abstract class Vehicle
{
    // Setting these to public for demonstration only, otherwise you should set these 
    //  to protected and write public accessors 
    public $paintType;
    public $bodyType;
    public $interior;
}

class Car extends Vehicle
{
}

class Suv extends Vehicle
{
}

class Truck extends Vehicle
{
}

class GasStation
{
    public static function cleanVehicle(Vehicle $vehicle)
    {
        switch (get_class($vehicle)) {
        
            case 'Car':
                // Car specific cleaning
                break;

            case 'Truck':
                // Truck specific cleaning
                break;

            default:
                throw new Exception(sprintf('Invalid $vehicle: %s', serialize($vehicle)));
        }

        // We've gone through our vehicle specific cleaning, now we can do generic
        if ('Leather' === $vehicle->getInterior()) {
            // Leather specific cleaning
        }

        if ('Sedan' === $vehicle->getBodyType()) {
            // Sedan specific cleaning
        }
    }
 }

$car = new Car();

$car->setPaintType = 'Glossy';
$car->setBodyType = 'Sedan';
$car->setInterior = 'Cloth';

$suv = new Suv();

$suv->setPaintType = 'Glossy';
$suv->setBodyType = 'Crossover';
$suv->setInterior = 'Leather';

$truck = new Truck();

$truck->setPaintType = 'Flat';
$truck->setBodyType = 'ClubCab';
$truck->setInterior = 'Cloth';

$vehicles = array($car, $suv, $truck);

foreach ($vehicles as $vehicle) {
    GasStation::cleanVehicle($vehicle);
}

Problem

Original source