JackRabbit and namespaces

[Wolf Benz]

Costin,
I had also posted the question to the JR mailing list. Thi sis the reply I got there, from Tobias (tobias.bocanegra@day.com)
__________
"Namespaces are fully supported by jackrabbit since 1.0. and the
registration works exactly as specified in jsr170 (which is a bit
troublesome).

in your application you probably have a 'getRepositorySession' call,
and there i would setup/check the namespaces for your application, eg:

1. check if your namespace is already registered
2. if not, do so.
3. setup the namespace mapping for your session and application.

example:

try {
s.getNamespaceURI("http://your.com/ns/1");
} catch (RepositoryException e) {
// register namespace
s.getWorkspace().getNamespaceRegistry().registerNa mespace(
"myapp", "http://your.com/ns/1");
}
s.setNamespacePrefix("myapp", "http://your.com/ns/1");
[....]
s.getRootNode().getNode("myapp:someNode");
"
_____________
It seems a bit inefficient having to check this at every getSession() call; it seems to make more sense having a kinda Session init() method - which leads me to my earlier conclusion; SessionFactory seems to be the best place to do this.
Hope it helps,
Wolf

[Wolf Benz]

Ref: MOD-303

Wolf

[Costin Leau]

I don't want to argue with the Day guys since they are the main authors behind JR but remapping an unregistration of the namespaces is not supported. Here is a snippet from Jackrabbit 1.2.2 (org.apache.jackrabbit.core.NamespaceRegistryImpl) :

/**
     * {@inheritDoc}
     */
    public void unregisterNamespace(String prefix)
            throws NamespaceException, UnsupportedRepositoryOperationException,
            AccessDeniedException, RepositoryException {
...
        /**
         * as we can't guarantee that there are no references to the specified
         * namespace (in names of nodes/properties/node types etc.) we simply
         * don't allow it.
         */
        throw new NamespaceException("unregistering namespaces is not supported.");

The same goes for remapping:

 public void registerNamespace(String prefix, String uri) {
...

     if (prefixToURI.containsKey(prefix)) {
            /**
             * prevent remapping of existing prefixes because this would in effect
             * remove the previously assigned namespace;
             * as we can't guarantee that there are no references to this namespace
             * (in names of nodes/properties/node types etc.) we simply don't allow it.
             */
            throw new NamespaceException("failed to register namespace "
                    + prefix + " -> " + uri
                    + ": remapping existing prefixes is not supported.");
        }

Maybe I'm missing something but the registration should be done through the Namespace registry which, as pointed about throws exceptions.

I'll take a look at the email but my understanding is that new registrations are allowed but modifications/removal of existing namespaces is forbidden.

[Wolf Benz]

Hi Costin,
I posted yoru finding to the JC list (rest assured, to spare you the FUD, I stripped yr name :-)
I will post their feedback back here.

Wolf

[bilobag]

Has there been any resolution to this issue or do I have to implement my own JackrabbitSessionFactory? It seems like an important issue to resolve. Ideally I would either like to have a parameter that specifies to re-register the node types or a way to just ignore the namespace if it already exists. Anybody have any suggestions or fixes to this issue? I just want to be able to have the nodetypes registered at startup through spring w/o throwing an exception if the namespace already exists. Any help is appreciated.

[Costin Leau]

MOD-303 has been resolved - see JIRA. Have you tried using the latest version of Spring Modules?
If you still encounter problems, please raise an issue on JIRA.

[bilobag]

Thanks for the quick reply. I do have the latest 0.8 version of springmodules. I have also taken a look at the source code. From what i've seen, it looks like the JackrabbitSessionFactory calls nodeTypeManager.registerNodeTypes(resource.getInpu tStream(), contentType); on line 67. This apparently calls the jackrabbit NodeTypeManagerImpl class. I noticed that this class has a registerNodeTypes(InputStream, String, boolean) method where the boolean declares whether to re-register existing nodeTypes. However, it looks like the JackrabbitSessionFactory uses the registerNodeTypes(InputStream, String) method which passes boolean=false to the registerNodeTypes(InputStream, String, boolean) method which means it will not re-register the nodeTypes. Is this how you intended this to work? If I understand this correctly, i think a parameter should be added to the JackrabbitSessionFactory class to determine whether to re-register existing node types. What do you think. The error below is what I am currently getting. I am getting this error because my custom nodetypes have already been registered and are being stored in the repository folder in an xml file. I would like to ideally have it just re-register my custom types so i don't get this exception on startup.


Caused by:
javax.jcr.RepositoryException: Invalid node type definition: {http://www.bmpcoe.org/jcr/cwe}content already exists: {http://www.bmpcoe.org/jcr/cwe}content already exists
at org.apache.jackrabbit.core.nodetype.NodeTypeManage rImpl.registerNodeTypes(NodeTypeManagerImpl.java:2 97)
at org.apache.jackrabbit.core.nodetype.NodeTypeManage rImpl.registerNodeTypes(NodeTypeManagerImpl.java:4 75)
at org.springmodules.jcr.jackrabbit.JackrabbitSession Factory.registerNodeTypes(JackrabbitSessionFactory .java:67)
at org.springmodules.jcr.JcrSessionFactory.afterPrope rtiesSet(JcrSessionFactory.java:126)

[hesspet]

I've the same problem:

Here's a part of my configuration

		<property name="contentType">
			<value>text/x-jcr-cnd</value>
		</property>			
		
		<property name="forceNamespacesRegistration">
			<value>true</value>
		</property>
		<property name="keepNewNamespaces">
			<value>true</value>
		</property>
			
		<property name="skipExistingNamespaces">
			<value>true</value>
		</property>

Is there an better solution available?

Thanks

Peter

[hookumsnivy]

Thanks for the quick reply. I do have the latest 0.8 version of springmodules. I have also taken a look at the source code. From what i've seen, it looks like the JackrabbitSessionFactory calls nodeTypeManager.registerNodeTypes(resource.getInpu tStream(), contentType); on line 67. This apparently calls the jackrabbit NodeTypeManagerImpl class. I noticed that this class has a registerNodeTypes(InputStream, String, boolean) method where the boolean declares whether to re-register existing nodeTypes. However, it looks like the JackrabbitSessionFactory uses the registerNodeTypes(InputStream, String) method which passes boolean=false to the registerNodeTypes(InputStream, String, boolean) method which means it will not re-register the nodeTypes. Is this how you intended this to work? If I understand this correctly, i think a parameter should be added to the JackrabbitSessionFactory class to determine whether to re-register existing node types. What do you think. The error below is what I am currently getting. I am getting this error because my custom nodetypes have already been registered and are being stored in the repository folder in an xml file. I would like to ideally have it just re-register my custom types so i don't get this exception on startup.


Caused by:
javax.jcr.RepositoryException: Invalid node type definition:

I'm having the same issue and I came to the same conclusion. Has there been any progress on this? Did you find another way perhaps?

[Costin Leau]

Could you please raise an issue ?

Thanks,