How to treat exceptions in constructor best?

Question

Hi,

How to treat exception in best way in construct?

option1 - catch exception where object created:

class Account {
    function __construct($id){
        if(empty($id)){
            throw new My_Exception('id can\'t be empty');
        }

        // ...
    }
}

class a1 {
    function just($id){
    try {
        $account = new Account($id);
    }
    catch(Exception $e){
        $e.getMessage();
    }
}

class a2{
    function just($id){
    try {
        $account = new Account($id);
    }
    catch(Exception $e){
        $e.getMessage();
    }
}

option2: catch exception inside __construct

class Account{
    function __construct($id){
    try{
        if(empty($id)){
            throw new My_Exception('id can\'t be empty');
        }

        // ...
    }
    catch(My_Exception $e) {

    }
}

Please write in which cases should be used option1 and in which should be used option2 or other better solution.

Thanks

Answer 1

What is the purpose of throwing an exception and immediately catching it? If you want to abort a function on error but not throw an error, you should return.

Thus, your first code is always correct. Let the Exception bubble up.

Answer 2

Of course, you should handle an exception thrown in a function outside this function, otherwise it won't make any sense. In regard to constructors specifically, try to avoid "new classname" as much as possible and stick to generator functions instead. For each class X, decide which class is responsible for creating objects of class X, and add a generator function to that class. This generator function is also the perfect place to handle X's constructor exceptions

 class AccountManager {
     function newAccount($id) {
        try {
           $obj = new Account($id);
        } catch....
           return null;
      }
 }

 // all other code uses this instead of "new Account"

 $account = $accountManager->newAccount($id);