[dom4j-user] onStart() method and path.getCurrent()

[Kenneth Reid Beesley]

I understand the basics of parsing an XML document with handlers, and  
the use of onStart() and onEnd().
However, I write to ask what kinds of information are available when  
the onStart() method is triggered.

Background:
I'm processing potentially large XML files that have structures like

<foo feature="value">
  <bar>...</bar>
  <bar>...</bar>
  ...
</foo>

wherein I might do well to capture each <bar> element and then detach  
it, to avoid keeping too much
XML structure in memory.   But before processing (and detaching) all  
the <bar> elements, I need
to get the value of the 'feature' attribute in the <foo> start tag.

If I have a handler like this

reader.addHandler("/foo", new ElementHandler() {

        public void onStart(ElementPath path) {

                // here I'd like to access the value of the 'feature' attribute,
                // but WITHOUT retrieving the whole <foo> element

                // this seems to work
                String val = path.getCurrent().attribute("feature").getValue() ;
                // but I worry about calling getCurrent()
        }
        public void onEnd(ElementPath path) {}
}

reader.addHandler("/foo/bar", new ElementHandler() {
        public void onStart(ElementPath path) {}

        public void onEnd(ElementPath path) {
                Element elmt = path.getCurrent() ;
                // do something with this <bar> element
                elmt.detach() ;
        }
}

Questions:

1.  What kinds of information are available when onStart() is  
invoked?  Are the start-tag attributes accessible without calling  
getCurrent()?

2.  In the onStart() method, when I invoke  
path.getCurrent().attribute("feature").getValue(), does the entire  
<foo> element get parsed into memory?
That's what I want to avoid.  When I encounter the <foo  
feature="value"> start tag, I'd just like to have access to the  
attributes.

Many thanks,

Ken

******************************
Kenneth R. Beesley, D.Phil.
P.O. Box 540475
North Salt Lake, UT
84054  USA






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