(PHP 5 >= 5.1.0, PHP 7)
Exception thrown if a value does not adhere to a defined valid data domain.
Quote: "In data management and database analysis, a data domain refers to all the values which a data element may contain."
Source: https://en.wikipedia.org/wiki/Data_domain
This exception has confused me a bit, DataDomainException, or DataTypeException may have been more descriptive.
I think this kind of exception is perfect to throw when expected the type of parameter, value etc. is good, but its value is out of domain. Look at RangeException:
>>Exception thrown to indicate range errors during program execution. Normally this means there was an arithmetic error other than under/overflow. This is the runtime version of DomainException.<<
So, this kind of exception is designed for logic error
When datatype is wrong, the better way is throwing InvalidArgumentException.
<?php
// Here, use InvalidArgumentException
function media($x) {
switch ($x) {
case image:
return 'PNG';
break;
case video:
return 'MP4';
break;
default:
throw new InvalidArgumentException ("Invalid media type!");
}
}?>
This is completly diffirent situation than this:
<?php
// Here, use DomainException
$object = new Library ();
try {
$object->allocate($x);
} catch (toFewMin $e) {
throw new DomainException ("Minimal value to allocate is too high").
}
?>
The simillar situation, but problem occurs during runtime:
<?php
class library {
function allocate($x) {
if ($x<1000)
throw new RangeException ("Value is too low!")
}
}
?>
Summary: DomainException corresponds to RangeException and we should use them in simillar situations. But first exception is designed to use when we are sure the problem is with our project, third-part elements etc. (simply: logical error), the second way is designed to use when we are sure the problem is with input data or environment (simply: runtime error).
<?php
function divide($divident, $divisor) {
if(!is_numeric($divident) || !is_numeric($divisor)) {
throw new InvalidArgumentException("Function accepts only numeric values");
}
if($divisor == 0) {
throw new DomainException("Divisor must not be zero");
}
return $divident / $divisor;
}
<?php
function renderImage($imageResource, $imageType)
{
switch ($imageType) {
case 'jpg':
case 'jpeg':
header('Content-type: image/jpeg');
imagejpeg($imageResource);
break;
case 'png':
header('Content-type: image/png');
imagepng($imageResource);
break;
default:
throw new DomainException('Unknown image type: ' . $imageType);
break;
}
imagedestroy($imageResource);
}
?>