Interface

If you have your own JTA Locator you can easily use it with DataNucleus. DataNucleus defines a TransactionManagerLocator interface and you need to implement this. .

package org.datanucleus.jta;

import javax.transaction.TransactionManager;
import org.datanucleus.ClassLoaderResolver;

public interface TransactionManagerLocator
{
    /**
     * Method to return the TransactionManager.
     * @param clr ClassLoader resolver
     * @return The TransactionManager
     */
    TransactionManager getTransactionManager(ClassLoaderResolver clr);
}

So you need to create a class, MyTransactionManagerLocator for example, that implements this interface.

Plugin Specification

Once you have this implementation you then need to make the class available as a DataNucleus plugin. You do this by putting a file plugin.xml in your JAR at the root of the CLASSPATH. The file plugin.xml will look like this

<?xml version="1.0"?>
<plugin id="mydomain.mylocator" name="DataNucleus plug-ins" provider-name="My Company">
    <extension point="org.datanucleus.jta_locator">
        <jta_locator name="MyLocator" class-name="mydomain.MyTransactionManagerLocator"/>
    </extension>
</plugin>

Note that you also require a MANIFEST.MF file as per the Extensions Guide.

Plugin Usage

The only thing remaining is to use your JTA Locator plugin. To do this you specify the persistence property datanucleus.jtaLocator as MyLocator (the name in plugin.xml).