Announcement: SAX2 1999-06-01 alpha release for Java

John Cowan cowan at
Wed Jun 2 18:05:30 BST 1999

David Megginson wrote:

> 1. Do we need a filter *interface* at all, or can a filter just be a
>    class that happens to implement Parser, Configurable,
>    EntityResolver, DTDHandler, DocumentHandler, and ErrorHandler?

Actually, a parser filter only *has* to implement Parser.  Whether
it implements the other things, or delegates their implementation
to private objects, is a detail.

>  (In
>    other words, is it enough to set the parent parser/filter in the
>    constructor?)

IMHO yes.  One could use reflection to determine whether there is
such a constructor, at least in the Java domain.
> 2. Actually, just last night I wrote an
>    org.xml.sax.helpers.FilterAdapter base class that filters can
>    easily be derived from (though they wouldn't have to be); by
>    default, it just lets all events sink down to the application,
>    and all configuration bubble up to the parser, but subclasses can
>    simply override methods to make changes in either direction.

I suggest you look at my P.D. code at; it would be easy to
enhance it for SAX2, and it handles some subtle points.

John Cowan		cowan at
	You tollerday donsk?  N.  You tolkatiff scowegian?  Nn.
	You spigotty anglease?  Nnn.  You phonio saxo?  Nnnn.
		Clear all so!  'Tis a Jute.... (Finnegans Wake 16.5)

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