Saxon

Legacy ID: #5308710 Legacy Poster: Yurgis (yurgis)

According to the JAXP spec, Templates must be threadsafe for a given instance over multiple threads running concurrently, and may be used multiple times in a given session. I wrote a little test case that shows the problem with thread safety with Saxon transformer. If you reduce number of concurrent threads from 10 down to 1 to reduce the size of the test.xml the problem will be gone. If you cannot reproduce the problem try to increase test.xml by duplicating some tags. Note that default transformer provided by JDK is working fine. This problem could be critical for web applications and web services relying on thread safety of the Templates instance. Main.java, test.xml, and test.xsl should be placed into the same package. Main.java: public class Main { public static void main(String[] args) throws Exception { //TransformerFactory factory = TransformerFactory.newInstance(); TransformerFactory factory = new net.sf.saxon.TransformerFactoryImpl(); StreamSource styleSource = new StreamSource( Main.class.getResourceAsStream("copy.xsl")); final Templates templates = factory.newTemplates(styleSource); DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance(); DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder(); final Document domDoc = docBuilder.parse( Main.class.getResourceAsStream("test.xml")); final NodeList sourceTags = domDoc.getElementsByTagName(""); ExecutorService executor = Executors.newFixedThreadPool(10); for (int i = 0; i < 100; i++) { executor.execute(new Runnable() { public void run() { try { Transformer transformer = templates.newTransformer(); DOMSource source = new DOMSource(domDoc); DOMResult result = new DOMResult(); transformer.transform(source, result); NodeList resultTags = ((Document)result.getNode()).getElementsByTagName(""); assert sourceTags.getLength() == resultTags.getLength(); System.out.println("thread-#" + Thread.currentThread().getId() + " OK"); } catch (Throwable ex) { System.err.println("thread-# " + Thread.currentThread().getId() + " ERROR"); ex.printStackTrace(); } } }); } executor.shutdown(); executor.awaitTermination(300, TimeUnit.SECONDS); } } copy.xsl: <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="xml"/> <xsl:template match="/"> <xsl:apply-templates/> </xsl:template> <xsl:template match="@* | node()"> <xsl:copy> <xsl:apply-templates select="@* | node()"/> </xsl:copy> </xsl:template> </xsl:stylesheet> test.xml: <alpha a="b" c="d"> <beta d="e"> <gamma f="g"/> <delta h="i">epsilon</delta> </beta> <beta d="e"> <gamma f="g"/> <delta h="i">epsilon</delta> </beta> <beta d="e"> <gamma f="g"/> <delta h="i">epsilon</delta> </beta> <beta d="e"> <gamma f="g"/> <delta h="i">epsilon</delta> </beta> <beta d="e"> <gamma f="g"/> <delta h="i">epsilon</delta> </beta> <beta d="e"> <gamma f="g"/> <delta h="i">epsilon</delta> </beta> <beta d="e"> <gamma f="g"/> <delta h="i">epsilon</delta> </beta> <beta d="e"> <gamma f="g"/> <delta h="i">epsilon</delta> </beta> </alpha>