Too many try/catch blocks. Is this proper?

Question

I've got an Input helper class that throws an exception if the source array index is undefined.

So if I had something like:

$input = new Input($_GET, $_POST);

$input->get("var1");
$input->get("var2");
$input->get("var3");
$input->get("var4");

It would now be:

$input = new Input($_GET, $_POST);

try {
    $input->get("var1");
} catch(Exception $e) {
    //handle it
}

try {
    $input->get("var2");
} catch(Exception $e) {
    //handle it
}

try {
    $input->get("var3");
} catch(Exception $e) {
    //handle it
}

try {
    $input->get("var4");
} catch(Exception $e) {
    //handle it
}

I have no idea how I could use less try catch blocks without having to stop execution of the further code if I was to put everything in 1 try catch block.

Is this the correct way of using the try catch function?

You might have one single `try{` ... `}catch` block around all your 4 `$input->get` calls. I can't guess why exception on `var1` should be handled differently than `var2`. After all, exceptions are usually for exceptional situations ! — Basile Starynkevitch, Apr 25 '14 at 14:30
Yeah, but my problem is that it stops executing the further `$input->get()` calls if an exception occurs at the first call. — Kid Diamond, Apr 25 '14 at 14:32

score 3 · Answer 1 · answered Apr 25 '14 at 14:31

3

Why not this:

try {
    $input->get("var1");
    $input->get("var2");
    $input->get("var3");
    $input->get("var4");
} catch(Exception $e) {
    //handle it
}

answered Apr 25 '14 at 14:31

Noman Ghani

468
3
9

if var1 will fail all will fail therefor this is not the wanted result – user3232725 Apr 25 '14 at 14:33
3

Funny, it's the same code in the accepted answer, where this one was answered first. @user3232725 Although no further explanation was given, still remains as acceptable. – Funk Forty Niner Apr 25 '14 at 14:47

score 1 · Accepted Answer · answered Apr 25 '14 at 14:32

Do you really need to handle every exception individually? e.g. would

try {
   $input->get('var1');
   $input->get('var2');
   $input->get('var3');
   $input->get('var4');
} catch (Exception $e) {
  ... do something
}

work just as well? With this construct, any of the get() calls that fail would trigger the catch and further get() calls will not be performed. e.g if var2 throws, then var3 and var4 will never be gotten.

score 0 · Answer 3 · answered Apr 25 '14 at 14:33

0

I woudn't add so many try catches. It's a pain to develop and maintain. You will thank yourselfs if you can push it back to one method.

Even better what i would recommend is:

if(isset($input->get("var4")))
$input->get("var4")

or

function get($name){
 if(isset($this->get($name)))
   return $this->get($name);

 return false; //or throw an exception/error here :)
}

answered Apr 25 '14 at 14:33

user3232725

218
1
6

One problem with this is that the `get` method might be doing something resource- or time-intensive, and you're calling it twice each time you want to `get` something. – Kryten Apr 25 '14 at 14:49

score 0 · Answer 4 · answered Apr 25 '14 at 14:35

It depends on what you'd like to achieve. If you'd like to break code execution after any of getters fail, you should use HeroFTime solution. If you'd like to handle each getter separately it's better to write a function that encapsulates the try/catch as follows:

function getter($input, $value) {
  try {
     return $input->get($value);
  } catch(Exception $e) {
     return null; // or any default value you'd like to provide
  }
}

Too many try/catch blocks. Is this proper?

4 Answers4

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