On 12/13/01 5:34 AM, "Christian Nentwich" <[EMAIL PROTECTED]> wrote:
> On Thu, 2001-12-13 at 04:49, Geir Magnusson Jr. wrote:
>> I am not overjoyed with the solution, it's only for dom4j (at the moment),
>> but I tried to limit the object creation, it's only O(treesize) and it
>> reverts (supposed to anyway) to the old way for non-supported node types.
>
> O(treesize) sounds pretty harsh actually. I'm querying 30 megabyte
> documents.. Do you think something clever can be done to speed it up?
Ok - learning a bit as I go along. I'll fess-up that it's hard - I am
unfamiliar with most of the Xpath basics (but learning as rapidly as I
can...) So there may be conceptual holes...
Forget that stupid gather thingy I did last night. Turns out I can use your
generic solution, the Navigator :)
So here is the next try. It still sucks in that it's at worst O(size), but
it's getting better, and doesn't do a pre traversal..
>From DefaultUnionExpr
public Object evaluate(Context context) throws JaxenException
{
List results = new ArrayList();
List lhsResults = convertToList( getLHS().evaluate( context ) );
List rhsResults = convertToList( getRHS().evaluate( context ) );
Navigator nav = context.getNavigator();
List nodes = context.getNodeSet();
int size = nodes.size();
/*
* do this only while there are nodes to sort
*/
for( int i = 0;
i < size && ( lhsResults.size() > 0 || rhsResults.size() > 0 );
i ++)
{
/*
* for each node in this context, get ordered decendant iterator
*/
Iterator it = nav.getDescendantAxisIterator( nodes.get(i) );
/*
* again, only if something to do...
*/
while( it.hasNext()
&& ( lhsResults.size() > 0 || rhsResults.size() > 0 ))
{
Object n = it.next();
if ( lhsResults.remove( n ) )
results.add( n );
else if (rhsResults.remove( n ) )
results.add( n );
}
}
return results;
}
--
Geir Magnusson Jr. [EMAIL PROTECTED]
System and Software Consulting
"Whoever would overthrow the liberty of a nation must begin by subduing the
freeness of speech." - Benjamin Franklin
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