XOM API for Processing XML with Java

[Elliotte Harold <elharo AT metalab.unc.edu>]

Currently in CanonicalXMLSerializer methods such as setLineSeparator() 
and setMaxLength() ignore their arguments because the canonicalization 
algorithm sets certain required values for these properties. For 
example, in caonical XML the line break must be a linefeed. Therefore 
the code for setLineSeparator() looks like this:

  public final void setLineSeparator(String lineSeparator) {
      super.setLineSeparator("\n");    }

I have an open question as to whether I should throw an exception if 
someone passes in something else such as "\r". Is it better to silently 
do the right and required thing here? (current behavior) or should I 
warn clients when they attempt to do the wrong thing by throwing an 
IllegalArgumentException?  I'm leaning toward throwing the exception, 
but I'm open to discussion and argument about this. I'd also be curious 
if anyone has references to suggested programming practices (e.g. Bloch 
item #s) that are squarely on point here.

Hmm, one more point that argues in favor of throwing the exception: the 
superclass (Serializer) variants of these methods to throw exceptions 
when illegal values such as NEL are passed to these methods. So it's not 
out of the question or unexpected for these methods to throw an 
IllegalArgumentException. On the other hand throwing the exception for 
different values the superclass will accept means I'd be tightening the 
preconditions on the subclass implementation. I think Bertrand Meyer 
(Object Oriented Software Construction) claims I'm not allowed to do that.

--
Elliotte