Re: NYIException

[Stuart Ballard]

Andrew Haley wrote:
> Out of interest (and please forgive me if this has already been
> discussed at length) why have dummy methods at all?  Wouldn't it be
> better to have a compile time failure for unimplemented methods?

One reason is that it makes it possible to compile code against 
Classpath that includes references to methods that Classpath hasn't yet 
implemented. This code might run just fine for the purpose you need it, 
because the unimplemented calls are in a codepath that you aren't taking.

Another reason to have NYIError[1] is that in some cases a method may be 
implemented for some cases and not others, depending on its arguments. 
For example, a method might not have the correct behavior implemented as 
fallback for when one of its arguments is null, or might only work for 
particular subclasses of the class it's supposed to take as an argument. 
In that case, throwing the Error can be done conditionally, which is 
something that couldn't be replicated at compile time.

Stuart.

[1] yes, I vote for Error, FWIW, but I could live with anything that's a 
distinct class - ie not 'new RuntimeException("NYI")' - wherever it's 
placed in the Exception hierarchy.


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Stuart Ballard, Senior Web Developer
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