You can use @throws in the PHPDoc comment, and the IDE will recognize this function as throwing an exception, when viewing the doc, however unlike Java it will not force you to implement the Try{}catch block. Maybe future versions of the IDE (I am using InteliJ 11) will mark those places where try{}catch is expected, … Read more
Try it and see: def failure(): raise ValueError, “Real error” def apologize(): raise TypeError, “Apology error” try: failure() except ValueError: apologize() raise The result: Traceback (most recent call last): File “<pyshell#14>”, line 10, in <module> apologize() File “<pyshell#14>”, line 5, in apologize raise TypeError, “Apology error” TypeError: Apology error The reason: the “real” error from … Read more
You are pretty much right on. Except for one thing I’ll mention in a bit. throws is as much a part of the method API as the name and the parameters. Clients know if they call that method, they need to handle that exception–by simply throwing it also or by catching it and handling it … Read more
For more detailed reasoning, see: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3051.html As expressed in the national body comment above, exception specifications have not proven useful in practice. There are numerous discussions of the problems with exception specifications in C++ (see, e.g., [Sutter02], [Boost03]), but the main issues are: Run-time checking: C++ exception specifications are checked at runtime rather than at … Read more
The recommended way is to throw by value and catch by reference. Your example code throws a pointer, which is a bad idea since you would have to manage memory at the catch site. If you really feel you should throw a pointer, use a smart pointer such as shared_ptr. Anyway, Herb Sutter and Alexei … Read more
If you do a throw; on its own, and there isn’t a current exception for it to rethrow, then the program ends abruptly. (More specifically, terminate() is called.) Note that throw; is the only safe way to re-throw the current exception – it’s not equivalent to catch (exception const & e) { throw e; }
Actually, the standard is very precise here. [except.handle]/17: When the handler declares a reference to a non-constant object, any changes to the referenced object are changes to the temporary object initialized when the throw-expression was executed and will have effect should that object be rethrown. And [except.throw]/8: A throw-expression with no operand rethrows the currently … Read more
I was an early proponent of typed errors in Swift. This is how the Swift team convinced me I was wrong. Strongly typed errors are fragile in ways that can lead to poor API evolution. If the API promises to throw only one of precisely 3 errors, then when a fourth error condition arises in … Read more
throws : Used when writing methods, to declare that the method in question throws the specified (checked) exception. As opposed to checked exceptions, runtime exceptions (NullPointerExceptions etc) may be thrown without having the method declare throws NullPointerException. throw: Instruction to actually throw the exception. (Or more specifically, the Throwable). The throw keyword is followed by … Read more
I would recommend you never throw NullPointerException by yourself. The main reason not to do this, as Thorbjørn Ravn Andersen says in a comment below, is that you don’t wan’t to mix ‘real, bad NPEs’ with NPEs thrown intentionally. So, until you’re confident that you’re able to recognize ‘valid’ NPE, I’d recommend to use IllegalArgumentException … Read more