Re: Exceptions: Error Codes Vs Class Names

On Fri, 27 Aug 2004 23:45:50 -0400, Davey <davey@php.net> wrote: > Hey PEARs, Greg, > > I am not trying to start another debate, I just want to state some facts! > > I have done some benchmarking with some fake code, one using a single > class with a class constant for each type of error, and one using a > seperate class for each type of error. > > I chose the rather random number of 30 errors in each case (so in the > first there was 30 constants and the second 30 classes). > > I ran the random scenario that error 17 was thrown in each case, and > caught it. > > My findings are this: > > The definition of a single class with 30 constants is about 4 times > faster than of the 30 seperate classes, however: > > because with the single class we have to check the error code using: > > catch (errors $exception) { > if ($exception->getCode() == exception_class::CONST) { > echo $exception; > } > } > > as opposed to with the other method which means only the error we want > to check for is caught: > > catch (error17 $exception) { > echo $exception; > } > > it turns out to be *marginally* faster. > > Therefore, the only issue we need to work out is, what if what we're > "try{}ing" can throw more than one exception? i.e. we're connecting to a > DB, running a query, checking the result - thats 3 seperate errors. > With the single class, we have one catch block. With the seperate > classes, we need three catch blocks, or we need a parent class. Now, > whilst we have a default parent class (Exception) catching all of these > (or just our own parent class) means we need to do if ($exception > instanceof Error17) which presumably will make it slower (not tested > that far yet). > > But from my initial findings, I would say that by grouping errors into > relevant single classes (either per package, or for each large procedure > (i.e. user login)) is the fastest and most efficient way to do it. > > This is the first point I've disagreed with you upon Greg, I hope that > cold hard facts will persuade you (and everyone else) that perhaps > seperate classes is not the way to go. > > Certainly I hope this at least shows we need more testing before > deciding which way to go. > Ok, I can accept that the single class is faster. If we use that, how will re-throwing work? I suppose we can wrap the exception (as stated in the RFC), but this means: 1) 2 objects instead of 1 will be in that throw now. 2) Another object instatiation due to the above 3) another call to throw, due to the above 4) Possibly re-setting the code Whereas if you catch the specific error you want, it will bubble-up automatically. -- DB_DataObject_FormBuilder - The database at your fingertips http://pear.php.net/package/DB_DataObject_FormBuilder paperCrane --Justin Patrin--