On 10/5/14, 11:31 PM, Jacob Carlborg wrote:
On 05/10/14 18:18, Andrei Alexandrescu wrote:
Exceptions are all about centralized error handling. How, and how often,
would you handle FileNotFoundException differently than
PermissionDeniedException?
Probably not that often. But I don't think it's up to "File" to decide
that. I think "File" should throw a specific error as possible
containing all details it has.
Sure, but that can be distinguished by payload, not type.
Then it's up to the user of "File" how to
handle the exception. If you're not interested in the differences
between FileNotFoundException and PermissionDeniedException, then catch
the base class instead.
The details provided between these two exception could be different as
well. FileNotFoundException should contain the path of the file that
wasn't found. PermissionDeniedException should contain some information
about if it was the source or target that caused the exception to be
thrown. Think of a copy or move operation.
How would one localize error messages if the specific exception is not
known?
Knowledge doesn't have to be by type; just place data inside the
exception. About the only place where multiple "catch" statements are
used to make fine distinctions between exception types is in sample code
showing how to use multiple "catch" statements :o). This whole notion
that different exceptions need different types is as far as I can tell a
red herring.
Andrei
