Is it possible to declare that in a function you launch an exception with PHP?

Question

With a small example:

public function calcularMedia($valor){
    if($valor < 0){
        //LANÇAR EXCEÇÃO
    }
    else if($valor > 6){
        return "Passou";
    }else{
        return "Recuperação";
    }
}

Remembering this function is called by another, which has a block try and a catch then I wonder if it is possible to throw an exception in my function to calculate average if the reported value is less than 0.

Answer 1

You cannot explicitly state (checked Exception) that a function can cast an exception because PHP is not Java, the only language that allows it, and it did not work.

You can make an exception as simple as possible, but if you do this you will be programming like Java, so if you want to code in Java, go to Java.

Technically you can do this:

public function calcularMedia($valor) {
    if ($valor < 0) throw new ValorNegativoException();
    return $valor > 6 ? "Passou" : "Recuperação";
}

You would have to create your own exception for this. If you’re not gonna do it right then why use this mechanism?

Some people would rather do this, but it’s abuse of the mechanism:

public function calcularMedia($valor) {
    if ($valor < 0) throw new Exception("Valor Negativo");
    return $valor > 6 ? "Passou" : "Recuperação";
}

You can at least make a compromise, in some cases it’s ok:

public function calcularMedia($valor) {
    if ($valor < 0) throw new InvalidArgumentException("Valor Negativo");
    return $valor > 6 ? "Passou" : "Recuperação";
}

But PHP might just be:

public function calcularMedia($valor) {
    if ($valor < 0) return false;
    return $valor > 6 ? "Passou" : "Recuperação";
}

I put in the Github for future reference.

Then you test if it came false and doesn’t need a try-catch, you only accept a value if it is different from false. It is more correct because you expect it to happen, it is not an exceptional situation.

If you don’t understand very deeply how to use exception correctly it is better not to use, because PHP was created all without thinking about it. It is true that lately they are encouraging more its use, which makes the language lose identity and starts to become Java. Java is a much better Java than PHP. PHP is a phenomenal PHP and exception should be something exceptional in code. Even Java has moved away from exception.

You can read more on:

• What are Exceptions?
• Exception is not flow control
• It is good practice to make an exception in such cases?