you should create the list of entities inside iterator() call, not
hold on to it in a field. see the phonebook example.
-igor
On Thu, Nov 5, 2009 at 7:06 PM, <b...@actrix.gen.nz> wrote:
> Thanks again Igor.
>
> I have switched to plain IDataProvider as suggested, although I have
> to admit that I still have to look at the phonebook example.
>
> Again, IDataProvider is an improvement, but still not good.
>
> It appears that SerializableChecker is complaining about a volatile
> field not being Serializable. Is this a bug or do I miss anything?
>
> I think that SerializableChecker is a wondeful tool, that is why I am
> persevering:
>
> org.apache.wicket.util.io.SerializableChecker$WicketNotSerializableException:
> Unable to serialize class: MyEntity
>
> ...
> private volatile java.util.List MyEntityDataProvider.entities
> [class=java.util.Vector]
>
> ...
>
>
> public class MyEntityDataProvider implements IDataProvider<MyEntity>{
>
> private final Integer searchId;
> private volatile List<MyEntity> entities;
>
> public MyEntityDataProvider(Integer searchId) {
> this(searchId, null);
> }
>
> public MyEntityDataProvider(Integer searchId, List<MyEntity>
> entities) {
> this.searchId = searchId;
> this.entities = entities;
> }
>
> �...@override
> public Iterator<MyEntity> iterator(int first, int count)
> {
> return entities.iterator();
> }
>
> �...@override
> public int size()
> {
> if(this.entities == null){
> SessionLocal sessionBean = MyApplication.getSessionBean();
> this.entities = sessionBean.getMyEntities(this.searchId);
> }
> return this.entities.size();
> }
>
> �...@override
> public IModel<MyEntity> model(MyEntity entity)
> {
> return new DetachableMyEntityModel(entity);
> }
>
> �...@override
> public void detach()
> {
> }
>
> }
>
>
>
>
> On Thu, 5 Nov 2009 18:30:20 -0800, you wrote:
>
>>no, you should not be using listdataprovider, it is only for static
>>lists of things.
>>
>>if you want best practice look at the phonebook example in wicket-stuff.
>>
>>-igor
>>
>>On Thu, Nov 5, 2009 at 5:52 PM, <b...@actrix.gen.nz> wrote:
>>> Igor,
>>>
>>> Thanks very much for your suggestion which I followed.
>>>
>>> I have overridden it and that is an improvement but still not good.
>>>
>>> ListDataProvider dataProvider = new ListDataProvider(myList){
>>> �...@override
>>> public IModel<MyEntity> model(Object object)
>>> {
>>> return new DetachableMyEntityModel((MyEntity) object);
>>> }
>>> };
>>>
>>> SerializableChecker does a nice job spotting:
>>>
>>> ...
>>> private final java.util.List
>>> org.apache.wicket.markup.repeater.data.ListDataProvider.list[write:1]
>>> [class=[Ljava.lang.Object;]
>>>
>>> private final java.util.List
>>> org.apache.wicket.markup.repeater.data.ListDataProvider.list[write:1][0]
>>> [class=MyEntity] <----- field that is not serializable
>>>
>>> I guess that private final List<T> list; of ListDataProvider wants to
>>> be serialized into the session which we don't want?
>>>
>>> I am trying to apply best practice - may be I should not be using
>>> ListDataProvider?
>>>
>>> http://old.nabble.com/How-to-avoid-Lazy-loading-exception-td17040941.html
>>>
>>> "instead of using listdataprovider you should use a dataprovider in
>>> that uses detachablemodels for each individual item -igor "
>>>
>>> Today, with 1.4, what is best to use for <List> results from
>>> EntityManager? Still DataProvider?
>>>
>>> Many thanks,
>>>
>>> Bernard
>>>
>>>
>>>
>>> On Thu, 5 Nov 2009 14:25:01 -0800, you wrote:
>>>
>>>>you have to override listdataprovider#model and return a detachable model.
>>>>
>>>>-igor
>>>>
>>>>On Thu, Nov 5, 2009 at 2:19 PM, <b...@actrix.gen.nz> wrote:
>>>>> Hi,
>>>>>
>>>>> I am trying to prevent the leaking of business objects into the
>>>>> session.
>>>>>
>>>>> Michael made a good comment in
>>>>>
>>>>> http://www.mail-archive.com/users@wicket.apache.org/msg31187.html
>>>>>
>>>>> "... you could e.g. temporarily remove the "Serializable" from your
>>>>> model-classes and go spotting nonserializable exceptions until they
>>>>> don't ocurr anymore."
>>>>>
>>>>> which is what I did.
>>>>>
>>>>> It works nicely until I hit a problem with ListDataProvider in
>>>>> DataView, where I get an exception even if I use LDMs:
>>>>>
>>>>> java.lang.ClassCastException: MyEntyty cannot be cast to
>>>>> java.io.Serializable at
>>>>> org.apache.wicket.markup.repeater.data.ListDataProvider.model(ListDataProvider.java:35)
>>>>>
>>>>> It appears to me that the approach has a conflict with framework
>>>>> classes.
>>>>>
>>>>> What is the best way to spot session memory issues without hitting
>>>>> this problem?
>>>>>
>>>>> Many thanks,
>>>>>
>>>>> Bernard
>>>>>
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>>>>>
>>>>
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