How can I get the current entity values from loadClassMetadata?

Question

In my legacy database, the entities are dispatched depending on the value of an attribute. For example, the tables are called:

• tv_rec
• mobi_rec
• blah_rec

and the payload I receive may be something like:

{
  "label": "The TV set",
  "domain": "TV",
  "price": 456.78
}

or

{
  "label": "One mobile phone",
  "domain": "mobi",
  "price": 123.45
}

The Entity is defined as:

// all the necessary ApiPlatform stuff
class Prod {
  private string $label;
  private float $price;
// getters and setters follow.
// Note that there is no "domain" attribute as this information is contained in the table name itself.
}

I need to chose the right table depending on the value of domain and for that, I plan to use loadClassMetadata but there is no access to the values of the entities.

How can I know which entity I'm currently acting on when I'm inside the loadClassMetadata event, in order to retrieve this value?