xml-dev - Re: SAX: towards a solution

[David Megginson <ak117@freenet.carleton.ca>]

James Clark writes:

 > I don't think using java.util.Dictionary is a good idea:
 > 
 > 1. JDK 1.2 provides a new Map interface which replaces Dictionary.
 > 
 > 2. java.util.Dictionary is an abstract base class not an interface.
 > 
 > 3. java.util.dictionary is weakly typed: it doesn't enforce the
 > requirement that keys be strings, and it requires values to be cast to
 > strings.
 > 
 > I think it would be much better to have an Attributes interface and also
 > a convenience adapter class that provides a Dictionary implementation in
 > terms of that interface.

I would like to avoid java.util.Map to keep SAX applet-friendly (it
will be years before most browsers deployed support even 1.1).  I
agree that Dictionary is far less than ideal -- what do you imagine
the attributes interface looking like?

 > >   charData (char ch[], int length)
 > 
 > I think there should be an offset argument as well.  Most of the Java
 > String operations that operate on a subarray take 3 arguments: char
 > array, offset and count.

Agreed.  I will change it to

  charData (char ch[], int start, int length);

 > > I am also assuming that we will provide not only a callback interface,
 > > but also an (optional) base class with stub methods that implementors
 > > can override as needed; that means that novice users will not have to
 > > implement all of SAX, even if we do end up with nine or ten methods.
 > 
 > I agree we should provide these. JDK 1.1 does this extensively in AWT:
 > it calls the base classes Adapters.  I think we should follow this
 > terminology.

Will the terminology translate well to other OO languages?  If so,
then I will be happy to use it.


All the best, and thank you for the comments,


David

-- 
David Megginson                 ak117@freenet.carleton.ca
Microstar Software Ltd.         dmeggins@microstar.com
      http://home.sprynet.com/sprynet/dmeggins/

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