FW: [Sax-devel] Problem with XMLReader

[Paul B. <pr...@fi...>]

I failed to CC: the list on the response...

> From: Joe...@vw... [mailto:Joe...@vw...]
> public interface ContentHandlerSource
> {
>     /**
>      * Call this method to get an XML document streamed to you via the
>      * passed ContentHandler
>      */
>     void writeToContentHandler(ContentHandler h) throws SAXException;
> }
> The logic behind it - sources of SAX events sometimes need to=20
> be configured at run-time. Writing an XMLReader for each is time=20
> consuming, and hard because InputSources aren't a good fit to many =
data=20
> sources (in-memory, DBs, etc).

Suggestions:

1) InputSource isn't final and XMLReader is an interface, so you can =
make your own versions that may be incompatible with other objects.  For =
example, if you have an XMLReader implementation that turns a JDBC =
rowset into a stream of SAX events, then you are free to subclass =
InputSource to get a JDBCRowsetInputSource that has get/setStatement() =
and get/setConnection() methods, etc., and then have an XMLReader =
implementation that does:

	public void parse(InputSource is) throws SAXException {
	  if (!(is instanceof JDBCRowsetInputSource)) {
	    throw new SAXException(is.getClass().getName() + " is not "
	      "a subclass of JDBCRowsetInputSource");
	  }
	  /* DO STUFF HERE */
	}

This particular suggestion is intended to provide a reasonable level of =
compatibility with other SAX consumers.  For instance, if you're using a =
TrAX-compliant XSLT processor, when it receives a SAXSource (XMLReader / =
InputSource pair), it does (or should do):

	ss.getXMLReader().parse(ss.getInputSource());

to generate events.  It's up to you to be sure that the InputSource =
subclass and XMLReader implementation are compatible.

2) You can create your own abstract class that has a =
pullFromSAX(XMLReader xr, InputSource is) method that attaches a =
ContentHandler, etc., and then calls parse on the supplied InputSource.

3) You can create a utility class with a static method that accepts a =
ContentHandler (and DeclHandler, etc., too?), XMLReader, and InputSource =
tuple and then performs the relevant operations.  In this case, your =
writeToContentHandler() would be equivalent to =
UtilityClass.consume(this,myXR,myIS);

Just some pre-coffee suggestions.

	-- Paul