[jira] Created: (JCR-2579) InvalidItemStateException when attempting concurrent, non conflicting writes

[Dan Diephouse (JIRA)]

InvalidItemStateException when attempting concurrent, non conflicting writes
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                 Key: JCR-2579
                 URL: https://issues.apache.org/jira/browse/JCR-2579
             Project: Jackrabbit Content Repository
          Issue Type: Bug
          Components: jackrabbit-core
    Affects Versions: 1.6.1
            Reporter: Dan Diephouse


I'm having some problems doing concurrent addition of nodes to a parent node in 
Jackrabbit.  I've attached a simple test which starts up a bunch of threads 
which add nodes to a parent node concurrently. If I add in locks I can get this 
to work, however according to the mailing list this should work without locks. 
However, the test always fails with this:

javax.jcr.InvalidItemStateException: Item cannot be saved because it has been 
modified externally: node /testParent
        at 
org.apache.jackrabbit.core.ItemImpl.getTransientStates(ItemImpl.java:281)
        at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:939)
        at 
org.mule.galaxy.impl.JackrabbitConcurrentWriteTest$1.run(JackrabbitConcurrentWriteTest.java:71)

I'm using Jackrabbit 1.6.1. Here is my (verbose) node type:

  <nodeType name="galaxy:noSiblings" 
    isMixin="false" 
    hasOrderableChildNodes="false"
    primaryItemName="">
    <propertyDefinition name="*" requiredType="undefined" 
onParentVersion="COPY" />
    <propertyDefinition name="*" requiredType="undefined" 
onParentVersion="COPY" multiple="true"/>
    <childNodeDefinition name="*" defaultPrimaryType="nt:unstructured" 
onParentVersion="COPY" sameNameSiblings="false" />
    <supertypes>
        <supertype>nt:base</supertype>
        <supertype>mix:referenceable</supertype>
        <supertype>mix:lockable</supertype>
    </supertypes>
  </nodeType>

And my test:    

package org.mule.galaxy.impl;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import javax.jcr.LoginException;
import javax.jcr.Node;
import javax.jcr.Repository;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.jcr.SimpleCredentials;

import junit.framework.TestCase;

import org.apache.commons.io.FileUtils;
import org.apache.jackrabbit.api.JackrabbitNodeTypeManager;
import org.apache.jackrabbit.core.RepositoryImpl;
import org.apache.jackrabbit.core.TransientRepository;
import org.apache.jackrabbit.core.config.RepositoryConfig;

public class JackrabbitConcurrentWriteTest extends TestCase {
    
    private Repository repository;
    private Session session;
    private String parentUUID;
    private boolean continueLoop = true;
    
    public void setUp() throws Exception {
        FileUtils.deleteDirectory(new File("repository"));
        File repoDir = new File("repository");
        repoDir.mkdirs();
        RepositoryConfig config = RepositoryConfig.create(new 
File("src/test/resources/META-INF/jackrabbit-repo-test.xml"), repoDir);
        repository = RepositoryImpl.create(config);
        session = createSession();
        
        createCustomNodeTypes(session);
        
        parentUUID = session.getRootNode().addNode("testParent", 
"galaxy:noSiblings").getUUID();
        session.save();
        session.logout();
    }

    private Session createSession() throws LoginException, RepositoryException {
        return repository.login(new SimpleCredentials("username", 
"password".toCharArray()));
    }
    
    public void testConcurrency() throws Exception {
        final List<Exception> exceptions = new ArrayList<Exception>();
        int threadCount = 20;
        final CountDownLatch latch = new CountDownLatch(threadCount);
        
        for (int i = 0; i < threadCount; i++) {
            Thread thread = new Thread() {

                @Override
                public void run() {
                    try {
                        while (continueLoop) {
                            Session session = createSession();
                            try {
                                Node node = session.getNodeByUUID(parentUUID);
                                node.addNode(UUID.randomUUID().toString());
                                node.save();
                                session.save();
                            } finally {
                                session.logout();
                            }   
                        }
                    } catch (RepositoryException e) {
                        exceptions.add(e);
                        continueLoop = false;
                    }
                    latch.countDown();
                }
                
            };
            thread.start();
        }
        
        latch.await(10, TimeUnit.SECONDS);
        continueLoop = false;
        
        for (Exception e : exceptions) {
            e.printStackTrace();
        }
        assertEquals(0, exceptions.size());
    }
    
    public void createCustomNodeTypes(Session session) throws 
RepositoryException, IOException {
        // Get the JackrabbitNodeTypeManager from the Workspace.
        // Note that it must be cast from the generic JCR NodeTypeManager to
        // the Jackrabbit-specific implementation.
        // (see: http://jackrabbit.apache.org/node-types.html)
        JackrabbitNodeTypeManager manager = (JackrabbitNodeTypeManager) 
session.getWorkspace().getNodeTypeManager();

        // Register the custom node types defined in the CND file
        InputStream is = Thread.currentThread().getContextClassLoader()
                .getResourceAsStream("org/mule/galaxy/impl/jcr/nodeTypes.xml");
        manager.registerNodeTypes(is, JackrabbitNodeTypeManager.TEXT_XML);
    }
}

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