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Subject: XOM API for Processing XML with Java

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  • From: Bruno Oliveira <bruno.oliveira360 AT gmail.com>
  • To: XOM API for Processing XML with Java <xom-interest AT lists.ibiblio.org>
  • Subject: Re: [XOM-interest] Processing XML file of 4GB
  • Date: Mon, 30 Apr 2012 12:50:32 +0100

Hi,
5 GB of memory isn't enought. In average, a XML file needs 4 or 5 times
more memory compared to the file size. For example, you have a file with
4GB, probably you will need to 12-15 GB of memory at least (depends of the
number of nested nodes per node). If you want to process the entire file, i
recomend you to use a Streaming-based API, e.g., StAX, or use the XOM
stream-based approach: http://www.xom.nu/faq.xhtml

Best Regards,
Bruno Oliveira

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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