XOM API for Processing XML with Java

[Geet Gangwar <geetgangwar AT gmail.com>]

Hi Michael,

Basically I need to perform some validation on the xml files. So my
requirement is to pick particular block from xml and validate that block.
For example say I want to pull all context i.e

XPATH expression like :  /xbrli:xbrl/xbrli:context

from the document and validate them.

Regards

Geet

On Mon, Apr 30, 2012 at 5:41 PM, Michael Kay <mike AT saxonica.com> wrote:

> NUX implements what one might call "chunked streaming": it selects a
> sequence of subtrees of your document and applies XQuery processing to
> each one in turn. (This is effectively the same as saxon:stream() in
> Saxon.) You need to have enough memory to hold the largest of these
> subtrees. Because your path /xbrli:xbrl effectively selects the whole
> document, your largest subtree is the same as the document size, so you
> aren't really streaming at all.
>
> If you can describe the query/transformation you want to carry out, then
> I might be able to suggest a way of doing it in a streamed manner either
> using NUX, or using native facilities of Saxon (whose streaming
> capabilities have advanced considerably since NUX was last released).
>
> Michael Kay
> Saxonica
>
>
> 2012/4/30 Geet Gangwar <geetgangwar AT gmail.com>
> >> Hi,
> >>
> >> I have a requirement of processing large XML files of about 4GB. I am
> using
> >> the NUX distribution to process the files.
> >> But when I fire a Xquery to this read this file, I get JAVA Heap Space
> >> error.
> >>
> >> I am using 64bit JDK1.6 and also I have increased the JVM size to 5 GB
> by
> >> -Xmx5G.
> >>
> >> Please help me how to solve this problem.
> >>
> >> I am pasting my sample code also.
> >>
> >> String path = "/xbrli:xbrl/";
> >>              Map prefixes = new HashMap();
> >>              prefixes.put("xbrli", "http://www.xbrl.org/2003/instance
> ");
> >>              prefixes.put("link", "http://www.xbrl.org/2003/linkbase";);
> >>              prefixes.put("xlink", "http://www.w3.org/1999/xlink";);
> >>              prefixes.put("xsd", "http://www.w3.org/2001/XMLSchema";);
> >>
> >>              StreamingTransform myTransform = new StreamingTransform() {
> >>                  private Nodes NONE = new Nodes();
> >>
> >>                  // execute XQuery against each element matching
> location
> >> path
> >>                  public Nodes transform(Element subtree) {
> >>                      Nodes results = XQueryUtil.xquery(subtree,
> >> "xbrli:context[id = 'c-01']");
> >>
> >>                      for (int i=0; i<  results.size(); i++) {
> >>                          // do something useful with query results;
> here we
> >> just print them
> >>
> >> System.out.println(XOMUtil.toPrettyXML(results.get(i)));
> >>                      }
> >>                      return NONE; // current subtree becomes subject to
> >> garbage collection
> >>                      // returning empty node list removes current
> subtree
> >> from document being build.
> >>                      // returning new Nodes(subtree) retains the current
> >> subtree.
> >>                      // returning new Nodes(some other nodes) replaces
> the
> >> current subtree with
> >>                      // some other nodes.
> >>                      // if you want (SAX) parsing to terminate at this
> >> point, simply throw an exception
> >>                  }
> >>              };
> >>
> >>              // parse document with a filtering Builder
> >>              StreamingPathFilter filter = new StreamingPathFilter(path,
> >> prefixes);
> >>              Builder builder = new
> Builder(filter.createNodeFactory(null,
> >> myTransform));
> >>              Document doc = builder.build(new
> File("F:/sample/cntxt.xml"));
> >>              System.out.println(doc.getRootElement().getValue());
> >>              System.out.println("doc.size()=" +
> >> doc.getRootElement().getChildCount());
> >>              System.out.println(XOMUtil.toPrettyXML(doc));
> >>
> >> Regards
> >>
> >> Geet
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