Returning a value in constructor function of a class

Question

So far I have a PHP class with the constructor

public function __construct ($identifier = NULL)
{
 // Return me.
if ( $identifier != NULL )
{
           


        

Answer 1

I'm really surprised that for 4 years none of the 22k viewers suggested creating private constructor and a method that attempts to create an object like this:

class A {
    private function __construct () {
        echo "Created!\n";
    }
    public static function attemptToCreate ($should_it_succeed) {
        if ($should_it_succeed) {
            return new A();
        }
        return false;
    }
}

var_dump(A::attemptToCreate(0)); // bool(false)
var_dump(A::attemptToCreate(1)); // object(A)#1 (0) {}
//! new A(); - gives error

This way you get either an object or false (you can also make it return null). Catching both situations is now very easy:

$user = User::attemptToCreate('email@example.com');
if(!$user) { // or if(is_null($user)) in case you return null instead of false
    echo "Not logged.";
} else {
    echo $user->name; // e.g.
}

You can test it right here: http://ideone.com/TDqSyi

I find my solution more convenient to use than throwing and catching exceptions.