I think this explanation will help:
http://www.datanucleus.org/products/accessplatform_1_1/jdo/orm/arrays.html
In short, stay away from array members because there is no good way for JDO
to detect when they've changed. If you absolutely must use an array you'll
need to reassign the entire field (as opposed to just setting individual
array elements) whenever you want it changed.
Hope this helps,
Max
On Fri, Aug 21, 2009 at 4:05 PM, Owen Powell <opow...@gmail.com> wrote:
>
> Hi everyone,
>
> I can't seem to persist an int[] field (but an int works fine).
>
> My object has three fields: a key, an int, and an array of ints. When
> I create and add the object to the datastore, all the fields are
> persisted correctly. However, when I later try to update the object,
> the int field updates correctly but the array does not.
>
> Is this how the datastore is supposed to work? Or is this a bug?
>
> Here is the datastore code, the object code follows.
>
> ---------- DATASTORE CODE -----------
>
> private static final PersistenceManagerFactory PMF =
>
> JDOHelper.getPersistenceManagerFactory("transactions-optional");
>
> // 1. CREATE and SAVE the TestObj (x = 1), storing the keyId.
> PersistenceManager pmt = PMF.getPersistenceManager();
> TestObj to = new TestObj();
> String keyIdT = null;
>
> try {
> pmt.makePersistent(to);
> keyIdT = to.getKey();
> } catch (Exception e) {
> e.printStackTrace();
> } finally {
> pmt.close();
> }
>
> // 2. CHECK that TestObj was saved correctly (x = 1), and then UPDATE
> fields (so that x = 2).
>
> pmt = PMF.getPersistenceManager();
> TestObj to2 = null;
>
> try {
> to2 = (TestObj)pmt.getObjectById(TestObj.class,
> keyIdT);
> to2.update();
> } catch (Exception e) {
> e.printStackTrace();
> } finally {
> pmt.close();
> }
>
> // 3. CHECK that TestObj was updated (does x = 2? for the int, yes,
> but for not for the first element of the array)
>
> pmt = PMF.getPersistenceManager();
> TestObj to3 = null;
> try {
> to3 = (TestObj)pmt.getObjectById(TestObj.class,
> keyIdT);
> } catch (Exception e) {
> e.printStackTrace();
> } finally {
> pmt.close();
> }
>
> ---------- OBJECT CODE -----------
>
> package com.test.db.client.theory;
>
> import javax.jdo.annotations.Extension;
> import javax.jdo.annotations.IdGeneratorStrategy;
> import javax.jdo.annotations.IdentityType;
> import javax.jdo.annotations.PersistenceCapable;
> import javax.jdo.annotations.Persistent;
> import javax.jdo.annotations.PrimaryKey;
>
> import com.google.gwt.user.client.rpc.IsSerializable;
>
> @PersistenceCapable(identityType = IdentityType.APPLICATION)
> public class TestObj implements IsSerializable {
>
> @PrimaryKey
> @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
> @Extension(vendorName="datanucleus", key="gae.encoded-pk",
> value="true")
> private String keyId;
>
> @Persistent
> public int x;
>
> @Persistent
> public int[] arrayOfX;
>
> public TestObj() {
> x = 1;
> arrayOfX = new int[1];
> arrayOfX[0] = 1;
> }
>
> public void update() {
> x++;
> arrayOfX[0]++;
> }
>
> public String getKey() {
> return keyId;
> }
>
> }
>
> >
>
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Google App Engine for Java" group.
To post to this group, send email to google-appengine-java@googlegroups.com
To unsubscribe from this group, send email to
google-appengine-java+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/google-appengine-java?hl=en
-~----------~----~----~----~------~----~------~--~---
