Visual Basic

<br />
try<br />
course = GetCourse(courseid)<br />
catch<br />
'error handle<br />
end try<br />
if course is nothing then<br />
' do something<br />
else<br />
'do something else<br />
end if<br />

<br />
try<br />
if GetCourse(courseid, course) then<br />
' do something<br />
else<br />
' do something else<br />
end if<br />
catch<br />
' error handle<br />
end try<br />

Kevin Brydon wrote:

If the first function handled all its exceptions internally it would return nothing when there was database error or there was no course with that ID in the database. The calling method wouldnt be able to tell what really happened.

Kevin Brydon wrote:

i dont think the calling method should care about how the function failed, just whether it did or not.

Kevin Brydon wrote:

Allowing the functions to throw out exceptions in my opinion is a bad idea if you can just handle them internally.

Guffa wrote:

Whether the method should return a null reference or throw an exception when it can not return an Course object, that depends on the reason. If it's normal for courses to be missing, it should return a null reference, but if the reason is that an error has occured, it should throw an exception.

supercat9 wrote:

Another possibility which may ease things for the caller would be to have similar versions of the function, one of which will throw an exception if it can't retrieve a course for any reason, and one of which will simply return nothing in the case where it can tell that a course does not exist (it will still throw an exception in case of things like database error and so forth).

Public Function GetCourseUnconditionally(courseId As Integer) As Course
   Course result = GetCourse(courseId)
   If result Is Nothing Then
      Throw New AppplicationException("Course not found.");
   End If
   Return result
End Function