On Thu, Dec 22, 2011 at 8:39 PM, Mat Lowery <[email protected]> wrote:
> My understanding of concurrent modifications is that I can receive an
> InvalidItemStateException if I have a stale view of the repository when my
> session is saved or my transaction is committed. However, I can get other
> exceptions using the code below. Furthermore, I thought Jackrabbit would
> allow concurrent child node additions to a single node given the child node
> names were unique.
correct
> So I wasn't even expecting an InvalidItemStateException
> for the code below.
>
> I understand that locking can prevent the InvalidItemStateException but I'm
> using transactions and committing the transaction for the sole purpose of
> exposing a lock is something I'd like to avoid at this time. I'd like to
> just catch the InvalidItemStateException and alert the user with a friendly
> message.
>
> Why do I get the given exceptions for the given code? I can supply full
> stacks if necessary; for now, just the class and error message are shown.
strange. i ran your test 20 times in a row on my macbook pro (os-x
10.7, java 6)
against the current head (svn r1222443). none of the runs failed.
cheers
stefan
>
> Jackrabbit 1.6.0:
> * org.apache.jackrabbit.core.state.ItemStateException: there's already a
> property state instance with id
> 243f6e39-7a3e-4d48-b051-9b4198a6a16b/{http://www.jcp.org/jcr/1.0}primaryType
> * javax.jcr.InvalidItemStateException: Item cannot be saved because it has
> been modified externally: node /
> * javax.jcr.InvalidItemStateException: node /: the node cannot be saved
> because it has been modified externally.
>
> Jackrabbit 1.6.5:
> * javax.jcr.InvalidItemStateException: node /: the node cannot be saved
> because it has been modified externally.
> * javax.jcr.InvalidItemStateException: Item cannot be saved because it has
> been modified externally: node /
> * org.apache.jackrabbit.core.state.ItemStateException: Child node entry with
> id 04afd8db-6515-4997-ac4e-83f066e39f53 has been removed, but is not present
> in the changelog
>
> Jackrabbit 2.3.4:
> * java.util.ConcurrentModificationException
> at java.util.WeakHashMap$HashIterator.nextEntry(WeakHashMap.java:762)
> at java.util.WeakHashMap$KeyIterator.next(WeakHashMap.java:795)
> at
> org.apache.jackrabbit.core.cache.CacheManager.logCacheStats(CacheManager.java:164)
>
> package test;
>
> import java.io.File;
> import java.util.concurrent.ExecutorService;
> import java.util.concurrent.Executors;
> import java.util.concurrent.TimeUnit;
> import java.util.concurrent.atomic.AtomicBoolean;
> import java.util.concurrent.atomic.AtomicInteger;
>
> import javax.jcr.Repository;
> import javax.jcr.RepositoryException;
> import javax.jcr.Session;
> import javax.jcr.SimpleCredentials;
>
> import org.apache.jackrabbit.core.TransientRepository;
>
> public class JackrabbitTest {
>
> public static void main(final String[] args) throws Exception {
> File dir = File.createTempFile("jackrabbit-test", "");
> dir.delete();
> dir.mkdir();
> System.out.println("created temporary directory: " +
> dir.getAbsolutePath());
> dir.deleteOnExit();
>
> final Repository jcrRepo = new TransientRepository(dir);
> final AtomicBoolean passed = new AtomicBoolean(true);
> final AtomicInteger counter = new AtomicInteger(0);
> ExecutorService executor = Executors.newFixedThreadPool(50);
> Runnable runnable = new Runnable() {
>
> @Override
> public void run() {
> try {
> Session session = jcrRepo.login(
> new SimpleCredentials("admin",
> "admin".toCharArray()));
> session.getRootNode().addNode("n" +
> counter.getAndIncrement()); //unique name
> session.save();
> session.logout();
> } catch (RepositoryException e) {
> e.printStackTrace();
> passed.set(false);
> }
> }
>
> };
> System.out.println("Running threads");
> for (int i = 0; i < 500; i++) {
> executor.execute(runnable);
> }
> executor.shutdown(); //Disable new tasks from being submitted
> if (!executor.awaitTermination(120, TimeUnit.SECONDS)) {
> System.err.println("timeout");
> System.exit(1);
> }
> if (!passed.get()) {
> System.err.println("one or more threads got an exception");
> System.exit(1);
> } else {
> System.out.println("all threads ran with no exceptions");
> System.exit(0);
> }
>
> }
>
> }
>
