This should be throwing an exception. The JavaDocs for
Transaction.commit() say
Commits the transaction. Whether this call succeeds or fails, all
subsequent method invocations on this object will throw
IllegalStateException.
When something does not work as you expect the first place to look is
the logs under your application console.
On 28 Feb 2010, at 05:25, Karel Alvarez wrote:
dont you get any exceptions stacktrace in the server console? it
would help... also you are calling commit() inside the for loop,
although the transactions is started only once... that would crash
in the second iteration in a normal db server, I am not sure what
GAE does with it, in any case I dont think it is what you intended...
On Sat, Feb 27, 2010 at 2:52 PM, Gunnar <[email protected]> wrote:
Hi,
I have problem with reordering a List.
I created a test with an entity called MyEntity which have a
List<SubEntity>.
First I persist one instance of MyEntity with a list containing 3
SubEntity.
This works fine. Then I call a reorder servlet that moves the first
SubEntity to the last position in the list.
The result is that the first SubEntity is lost and the datastore only
contains 2 SubEntity instances.
What can be wrong?
Here is the reorder code:
package com.google.appengine.demo;
import java.io.IOException;
import java.util.List;
import javax.jdo.PersistenceManager;
import javax.jdo.Query;
import javax.jdo.Transaction;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@SuppressWarnings("serial")
public class ReorderServlet extends HttpServlet {
@SuppressWarnings("unchecked")
public void doGet(HttpServletRequest req, HttpServletResponse
resp)
throws IOException {
PersistenceManager pm =
PMF.get().getPersistenceManager();
Query query = pm.newQuery(MyEntity.class);
Transaction tx = pm.currentTransaction();
try {
tx.begin();
List<MyEntity> results = (List<MyEntity>)
query.execute();
if (results.iterator().hasNext()) {
for (MyEntity e : results) {
List<SubEntity> list =
e.getMyList();
SubEntity first =
list.remove(0);
boolean ok = list.add(first);
if (!ok) {
System.err.println("could not add first");
}
System.out.println(list);
pm.makePersistent(e);
tx.commit();
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (tx.isActive())
tx.rollback();
query.closeAll();
pm.close();
}
resp.setContentType("text/plain");
resp.getWriter().println("reordered");
}
}
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