It seems like you code against a specific sub-type and not the parent class SMWDataItem as the method getBoolean() does only exist in the following sub-classes of SMWDataItem: SMWDIBoolean. Maybe you want to instanceof check for one of these explicitly?
Let’s take a look at an example:
abstractclassUser{/** @return string */abstractpublicfunctiongetPassword();}classMyUserextendsUser{publicfunctiongetPassword(){// return something}publicfunctiongetDisplayName(){// return some name.}}classAuthSystem{publicfunctionauthenticate(User$user){$this->logger->info(sprintf('Authenticating %s.',$user->getDisplayName()));// do something.}}
In the above example, the authenticate() method works fine as long as you just pass
instances of MyUser. However, if you now also want to pass a different sub-classes
of User which does not have a getDisplayName() method, the code will break.
classAuthSystem{publicfunctionauthenticate(User$user){if($userinstanceofMyUser){$this->logger->info(/** ... */);}// or alternativelyif(!$userinstanceofMyUser){thrownew\LogicException('$user must be an instance of MyUser, '.'other instances are not supported.');}}}
Note: PHP Analyzer uses reverse abstract interpretation to narrow down the types
inside the if block in such a case.
You can fix this by adding a namespace to your class:
When choosing a vendor namespace, try to pick something that is not too generic to avoid conflicts with other libraries.