On Nov 17, 2006, at 15:55, Glen Mazza wrote:
<snip />
2.) Methods setColor(), setFont(), setPaint(), setBackground(),
and clip() quietly just return and rely on the previous values if
the caller provides a NULL argument. It should set the value to
NULL instead and let the NPE occur naturally--that provides the
quickest way for the developer to realize that he or she goofed
up. If setFont(NULL) just relies on the previous value of the
font, as it does now, it is much harder to track the error further
downstream in the code. See [2].
Agreed.
I'd either let the NPE occur naturally, as Glen proposes, or at least
give the user-developer an indication that the use of a null argument
is dubious... I remember a similar situation in FOP's properties
package, but there, FOP itself was the only possible caller as the
class was not part of the public API. In FOP, I remember having opted
for a solution which explicitly prevented a null from being passed in
as an argument to the PropertyParser, since it looked as if nulls
were never supposed to make it in there.
Either nulls are acceptable as an argument --but then at least
something should happen, which is clearly not the case here-- or they
aren't. One only needs to ask the question: "Why would anyone
explicitly call those methods with a null argument?" You either set
the Color or you don't, but setting the Color to null makes very
little sense...
If Commons cannot contain a dependency on a logging library, then
Glen's proposal is the only right way to deal with this IMO. The
caller could then decide to allow this dubious use of the method and
catch the NPE (*), but Commons itself should not allow it (or at
least: it should not take this possibility into account).
(*) Note that it would be much better programming-style to avoid the
method from ever being called in that case, just like it is a sign of
bad style to try-and-catch an ArrayIndexOutOfBoundsException instead
of making sure beforehand that the index lies within the array's
bounds. A simple check to avoid the error is far more efficient than
waiting for an Exception to be thrown.
Just my 2 cents...
Cheers,
Andreas
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