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http://issues.apache.org/bugzilla/show_bug.cgi?id=34548 Summary: RE constructor is not thread safe Product: Regexp Version: unspecified Platform: Other OS/Version: Windows XP Status: NEW Severity: normal Priority: P2 Component: Other AssignedTo: regexp-dev@jakarta.apache.org ReportedBy: [EMAIL PROTECTED] We discovered that the RE constructor "new RE(pattern)" is not thread safe. I've attached a class which creates 1600 RE instances in their own threads running at random times and which illustrates the problem. The sample class includes an synchronisation wrapper which if invoked synchronizes the RE constructors and makes the problem go away. We might be submitting a patch for this; suggest anyone contact me before doing any work to fix this bug. To invoke the test class use the following command line. Usage : RegexSynchronizer -nosynch -nowrapper <delay> Example showing errors : RegexSynchronizer -nosynch -nowrapper 10 Example showing fewer errors because of lesser collisions : RegexSynchronizer -nosynch -nowrapper 30000 Example showing no errors because we wrap the RE usage : RegexSynchronizer -nosynch -wrapper 10 Options : -nosynch = runs tests without internal synchronisation -synch = runs tests with internal synchronisation -nowrapper = runs tests without internal synch wrapper -wrapper = runs tests with internal wrapper <delay> = internal random delay for each test; lower means more collisions Code follows : =============== package utility; import org.apache.regexp.*; import java.util.*; public class RegexSynchronizer { private static final String NO_SYNCH = "-nosynch"; private static final String SYNCH = "-synch"; private static final String NO_WRAPPER = "-nowrapper"; private static final String WRAPPER = "-wrapper"; public static synchronized RE getRegex(String thePattern) throws RESyntaxException { RE r = new RE(thePattern); return(r); } /** * Run some regexs in parallel to prove that the regex RE class is not thread safe. * * @param args . */ public static void main(String args[]) { boolean showUsage = false; if (args.length == 0) showUsage = true; boolean synch = false; boolean wrap = false; int delay = 10; for (int i = 0; i < args.length; i++) { String arg = args[i]; if (arg.equals(NO_SYNCH)) synch = false; else if (arg.equals(SYNCH)) synch = true; else if (arg.equals(NO_WRAPPER)) wrap = false; else if (arg.equals(WRAPPER)) wrap = true; else { try { int d = Integer.parseInt(arg); delay = d; } catch (NumberFormatException nfe) { showUsage = true; } } } if (showUsage) { System.out.println("Usage : \n" + "RegexSynchronizer " + NO_SYNCH + " " + NO_WRAPPER + " <delay>\n" + "\n" + "Example showing errors :\n" + "RegexSynchronizer " + NO_SYNCH + " " + NO_WRAPPER + " 10\n" + "\n" + "Example showing fewer errors because of lesser collisions :\n" + "RegexSynchronizer " + NO_SYNCH + " " + NO_WRAPPER + " 30000\n" + "\n" + "Example showing no errors because we wrap the RE usage :\n" + "RegexSynchronizer " + NO_SYNCH + " " + WRAPPER + " 10\n" + "\n" + "Options :\n" + NO_SYNCH + " = runs tests without internal synchronisation\n" + SYNCH + " = runs tests with internal synchronisation\n" + NO_WRAPPER + " = runs tests without internal synch wrapper\n" + WRAPPER + " = runs tests with internal wrapper\n" + "<delay> = internal random delay for each test; lower means more collisions" ); System.exit(-1); } System.out.println("Synch=" + synch + ", wrap=" + wrap + ", delay=" + delay); // To demonstrate the threading bug use the following settings : // doSynchronised = false // useOurSynchWrapper = false // sleepDelay = 10 // Change from false/true to test the two cases synchronised and not synchronised in the test code final boolean doSynchronised = synch; // Change from true/false to test the native class or our synchronized wrapper final boolean useOurSynchWrapper = wrap; // The amount of time the test threads sleep before starting. Increasing this reduces the likelihood of a threading problem // and hence reduces the number of errors we find. final int sleepDelay = delay; // Some sample regexs to try compiling String[] regexs = {"[A-Z]{3}:", "<TAG[^>]*>(.*?)</TAG>", "^[ \t]+", "\\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b", "(A:\\d{1,3}\\.){3}\\d{1,3}\\b", "(m/[0-9]{2}[\\/|-][0-9]{2}[\\/|-][0-9]{4}/)", "<a +href=\"http://([\\w\\.-]+)", "a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(<[b^>]*>)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c", "a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(<[b^>]*>)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c", "a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(<[b^>]*>)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c", "a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(<[b^>]*>)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c", "a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(a(<[b^>]*>)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c)c", "(A{1,5}){4}B{1,5}", "(A{1,5}){4}B{1,5}", "(A{1,5}){4}B{1,5}", "(A{1,5}){4}B{1,5}", "(A{1,5}){4}B{1,5}", "(A{1,5}){4}B{1,5}" }; // The number of test loops we do int numberOfTestLoops = 100; // ArrayList of test threads waiting to start ArrayList threads = new ArrayList(); // Random instance for thread sleep time final Random rand = new Random(); // Say we have started System.out.println("Start"); // Loop for the tests for (int i = 0; i < numberOfTestLoops; i++) { // For each test we compile each of our regexs for (int j = 0; j < regexs.length; j++) { final String pattern = regexs[j]; // Create a new thread to compile this regex Thread t = new Thread() { // Test method to compile the RE private void getRe() { int sleep = rand.nextInt(sleepDelay); try { // Randomise the start time for this thread so we get a different mix of tests each time through Thread.sleep(sleep); // Either use our wrapper or use the raw RE compiler if (useOurSynchWrapper) { RE r = RegexSynchronizer.getRegex(pattern); } else { RE r = new RE(pattern); } } catch (Throwable e) { // We should ideally never get here... System.out.println(e.toString() + ", " + pattern); } } // Run method for the thread public void run() { // If we're doing a synchronised test then synch here if (doSynchronised) { synchronized (Thread.class) { getRe(); } } else { // Otherwise do the unsynch test getRe(); } } }; // Store the thread ready to start them all together threads.add(t); } } // Start all the threads for (Iterator i = threads.iterator(); i.hasNext(); ) { Thread t = (Thread)i.next(); t.start(); } // Wait for the last one to finish try { Thread.sleep(sleepDelay + 1000); } catch (Exception ex) { // ignore } // Say we're done System.out.println("\nEnd"); } } -- Configure bugmail: http://issues.apache.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
