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<DIV><FONT face=Arial size=2>Hi There.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>I'm currently working on a long, long :-) project
in which we parse through some quite long files. We have tried converting these
files to XML for easier/standard parsing but each file will then be of a size of
about 16-30+ MB each. I don't even dare think about how much memory such a JDOM
tree would take! And the plans for lazy evaluation won't help, since we are
visiting every node in the tree, thus instantiating all objects anyway. Parsing
the trees solely using SAX is not developer-friendly enough. What I have in mind
is some kind of a XPath filter, allowing you to build JDOM trees from sub trees
from the data, and dipose these trees when I don't longer need that tree. Let me
give an example:</FONT></DIV>
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<DIV><FONT face=Arial size=2>We parse phone call records in files that sometimes
can contain thousands and thousands of records. In XML format these files and
records would look something like this:</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2><transferBatch></FONT></DIV>
<DIV><FONT face=Arial size=2> <phoneCall></FONT></DIV>
<DIV><FONT face=Arial size=2>
<details>bla.bla.bla., sub records etc.</details></FONT></DIV>
<DIV><FONT face=Arial size=2> </phoneCall></FONT></DIV>
<DIV><FONT face=Arial size=2>
<DIV><FONT face=Arial size=2> <phoneCall></FONT></DIV>
<DIV><FONT face=Arial size=2>
<details>bla.bla.bla., sub records etc.</details></FONT></DIV>
<DIV><FONT face=Arial size=2> </phoneCall></FONT></DIV>
<DIV>
<DIV><FONT face=Arial size=2> <phoneCall></FONT></DIV>
<DIV><FONT face=Arial size=2>
<details>bla.bla.bla., sub records etc.</details></FONT></DIV>
<DIV><FONT face=Arial size=2>
</phoneCall></FONT></DIV></DIV></FONT></DIV>
<DIV><FONT face=Arial size=2> ...</FONT></DIV>
<DIV><FONT face=Arial size=2> ...</FONT></DIV>
<DIV><FONT face=Arial size=2> ...</FONT></DIV>
<DIV><FONT face=Arial size=2></transferBatch></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Each <phoneCall> record with all it's sub
records can be quite large, and there can be thousands of these
<phoneCall> records. I'd like some way to get a JDOM tree for each
<phoneCall> record one at a time, and to be able to
dispose <phoneCall> JDOM tree before moving on to the next. How will
I do that?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>My Suggestion would be to insert an XPathFilter,
that only builds JDOM trees from the records that match the given XPath. In the
example above, an XPath of
transferBatch::phoneCall would have done the job.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Does my complaints/ideas sound completely
out-of-this-world? I think there are many out there who will have the same
problem, parsing one sub tree at a time, without regard to the
others.</FONT></DIV>
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<DIV><FONT face=Arial size=2>Regards,</FONT></DIV>
<DIV><FONT face=Arial size=2>Jakob Jenkov</FONT></DIV>
<DIV><FONT face=Arial size=2>jakob@jenkov.com</FONT></DIV>
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