How to handle edge case for a subscriber to not act on a specific object using the JMS/Serializer library?

Question

I am using the JMS/Serialzier library .

I have setup an Event-Subscriber, which listens for Events::PRE_SERIALIZE and I then convert all the object instances of an the class Price having the property currency and amount into different currencies.

public function onPreSerialize(PreSerializeEvent $event)
{
    $object = $event->getObject();
    $class = get_class($object);

    switch ($class) {
        case Price::class:
            return $this->currencyService->convertPrice($object);
    }
}

Yet now, in my application I have the edge case that one price belonging to one container object EdgeCase does not need to be converted at all:

use JMS\Serializer\Annotation\Type;
class EdgeCase {

    /**
     * @Type("Kopernikus\Price")
     * @var Price
     */
    private $price; // this one instance should not be handled by the event subscriber
}

but has to retain its original state. Yet I don't seem to be able to differentiate the origin of where my object is comming from.

I want to be able to configure which Price objects should be converted and when.

Answer 1

As a quick and dirty solution I have just created a StaticPrice class extending the Price and changed the instantiaton of for the Price object for that edge case.

I have added a further check in the subscriber, so the relevant subscriber looks like:

    switch ($class) {
        case Price::class:
            if ($object instanceof StaticPrice) {
                 break;
            }
            return $this->currencyService->convertPrice($object);
    }

Yet it feels wrong to solve this in such a hard-coded way on the object level; and that I have to change the logic creating the price objects. But it works for now.