DO NOT REPLY [Bug 27468] New: - CachedXPathAPI not thread-save

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http://nagoya.apache.org/bugzilla/show_bug.cgi?id=27468

CachedXPathAPI not thread-save

           Summary: CachedXPathAPI not thread-save
           Product: XalanJ2
           Version: 2.2.x
          Platform: PC
        OS/Version: Windows NT/2K
            Status: NEW
          Severity: Critical
          Priority: Other
         Component: org.apache.xpath
        AssignedTo: [EMAIL PROTECTED]
        ReportedBy: [EMAIL PROTECTED]


Version: Xalan bundled with jdk1.4.2_02 (crimson parser)

Using an instance of the CachedXPathAPI class from within multiple threads on a 
document that is not changed at runtime, causes inconsistent behaviour.

The source code below reproduces that problem on Windows NT (same is true for 
Linux RedHat7.3). Hint: I was only able to reproduce the problem when using a 
condition (e.g. [EMAIL PROTECTED]'a']) in the xpath statement.

----------------------------------------------------------

import java.io.*;
import javax.xml.parsers.*;

import org.apache.xpath.CachedXPathAPI;
import org.w3c.dom.*;
import org.xml.sax.*;

public class CachedXPathAPITest {

    private static final String XML = "<document><node id='a'>a</node><node 
id='b'>b</node><node id='c'>c</node></document>";
    private CachedXPathAPI _api;
    private Document _doc;

    public CachedXPathAPITest() throws Exception {
        _api = new CachedXPathAPI();
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder parser = factory.newDocumentBuilder();
        _doc = parser.parse(new InputSource(new StringReader(XML)));
        Thread t = null;
        for (int i=0; i<200; i++)
            t = new TestThread(_api, _doc);
        t.join();
    }

    public static void main(String[] args) throws Exception {
        new CachedXPathAPITest();
    }

    class TestThread extends Thread {

        private CachedXPathAPI _api;
        private Document _doc;

        TestThread(CachedXPathAPI api, Document doc) {
            _api = api;
            _doc = doc;
            start();
        }

        public void run() {
            try {
                for (int i=0; i<100; i++) {
                    String a = _api.eval(_doc, "/document/[EMAIL 
PROTECTED]'a']").str();
                    if (!a.equals("a"))
                        throw new RuntimeException(a + "!=a");
                    String b = _api.eval(_doc, "/document/[EMAIL 
PROTECTED]'b']").str();
                    if (!b.equals("b"))
                        throw new RuntimeException(b + "!=b");
                    String c = _api.eval(_doc, "/document/[EMAIL 
PROTECTED]'c']").str();
                    if (!c.equals("c"))
                        throw new RuntimeException(c + "!=c");
                }
            } catch (Exception e) {
                System.err.println(e);
            }
        }

    }

}