在哪里使用 JDO/Google App Engine 设置 TransactionOptions？

Question

我在 GAE 中使用 JDO 使用以下方法批量持久化对象：

public void makePersistent(PersistenceManager pm,
        List<Regeling> makePersistent) {        
    Transaction tx = pm.currentTransaction(); 
    try {
        // Start the transaction
        tx.begin();
        // Persist to the datastore
        // pm.makePersistentAll(makePersistent);
        for (int i = 0; i < makePersistent.size(); i += BATCH_SIZE) {
            int last = i + BATCH_SIZE;
            last = last > makePersistent.size() ? makePersistent.size()
                    : last;
            pm.makePersistentAll(makePersistent.subList(i, last));
            pm.flush();
            System.out.println("Made "+last+" items persistent.");
        }
        // Commit the transaction, flushing the object to the datastore
        tx.commit();
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (tx.isActive()) {
            // Error occurred so rollback the transaction
            System.out.println("Rolling back transaction");
            tx.rollback();
        }
        pm.close();
    }
}

这会中断：

javax.jdo.JDOUserException: One or more instances could not be made persistent
    at org.datanucleus.api.jdo.JDOPersistenceManager.makePersistentAll(JDOPersistenceManager.java:791)
    ...
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
NestedThrowablesStackTrace:

java.lang.IllegalArgumentException: cross-group transaction need to be explicitly specified, see TransactionOptions.Builder.withXGfound both

 Element {
  type: "PersistentServiceResultaat$RegelingInfoLijst$Regeling"
  name: "BWBR0001821"
}
 and 

 Element {
  type: "PersistentServiceResultaat$RegelingInfoLijst$Regeling"
  name: "BWBR0001822"
}

所以我尝试设置这些选项：

TransactionOptions ops = TransactionOptions.Builder.withXG(true);

但我找不到采用TransactionOptions 对象的方法。我可以在哪里设置这些选项？

Answer 1

设置在jdoconfig.xml:

<property name="datanucleus.appengine.datastoreEnableXGTransactions" value="true" />