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From Stephen Walsh <step...@connectwithawalsh.com>
Subject Re: Serialization of DAO
Date Thu, 14 Mar 2013 15:30:50 GMT
Thanks, Martin.  I intialize here, (which I just realized is not the best
spot):

    private void setUpMongo() {
        mongo = MongoUtil.getMongo();
        morphia = new Morphia().map(Blog.class).map(Person.class);
        blogDAO = new BlogDAO(mongo, morphia);
    }

I am using the Wicket Guice module, and I think your second point is what I
was getting at.  From learning about Guice (
http://www.youtube.com/watch?feature=player_embedded&v=hBVJbzAagfs), I
thought the point was to initialize once and then reuse wherever needed.  I
figured initialization would happen in the application class.  Maybe I'm
misunderstanding.  If it's supposed to happen in the application class,
then I don't really have need for a module because I don't have an
interface in this case, right?

Thanks for the help on this.

_______________________________________
Stephen Walsh | http://connectwithawalsh.com


On Thu, Mar 14, 2013 at 3:20 AM, Martin Grigorov <mgrigorov@apache.org>wrote:

> Hi,
>
> I don't see how you initialize blogDAO. If you don't use wicket-ioc module
> then you will need to lookup the DAO from the application whenever you need
> it:
>
> public void onSubmit() {
>
>   BlogDAO blogDao = MyApplication.get().getBlogDAO();
>   blogDao.save(blog);
> }
> This way you wont keep reference to it in the page/component and it wont be
> serialized.
>
> If you use wicket-guice module then you can do:
>
> @Inject
> private  BlogDAO blogDao;
>
> and use it anywhere.
> Wicket will use Guice to lookup the bean at component creation but the bean
> will be wrapped in a serializable proxy. That is a lightweight proxy will
> be (de)serialized with the page.
> This is the recommended way.
> wicket-string works the same way.
> wicket-cdi leaves the proxy creation to the CDI implementation.
>
>
>
> On Thu, Mar 14, 2013 at 5:19 AM, Stephen Walsh <
> stephen@connectwithawalsh.com> wrote:
>
> > I'm attempting to implement Guice for my DAO connections as my JBoss
> server
> > keeps running out of memory.  Not entirely sure why that is, but I'm
> hoping
> > this is at least part of it.  I read through
> > http://markmail.org/message/sz64l4eytzc3ctkh and understand why the DAO
> > needs to be serialized, and I also followed
> >
> >
> https://cwiki.apache.org/confluence/display/WICKET/Wicket%2C+Guice+and+Ibatis+exampleto
> > try and figure out where and how exactly to inject my DAO.
> >
> > My DAO already extends a basic DAO class that has all of the basics for
> > getting stuff from the database.  Neither of these are interfaces (not
> sure
> > if this is a problem or not).  My DAO works just fine in panels, but as
> > soon as it's on a page, it throws the not seralizable exception.
> >  Regardless it doesn't really solve the problem of really only needing
> one
> > DAO for the whole application instead of creating one whenever it's
> needed
> > in every place that it's needed.  If I understand dependency injection,
> > then this is the whole point.
> >
> > Here's my class.  Hopefully someone can point me in the right direction
> for
> > this page and my application class:
> >
> > public class EditBlogEntry extends BasePage {
> >
> >     private Logger logger = LoggerFactory.getLogger(EditBlogEntry.class);
> >
> >     private Mongo mongo;
> >     private Morphia morphia;
> >     private BlogDAO blogDAO;
> >
> >     public EditBlogEntry(final Blog blogEntry) {
> >  // Add edit blogPost form to page
> >         Form<?> form = new Form("form");
> >         form.add(new Button("postIt") {
> >             @Override
> >             public void onSubmit() {
> >                 // This merely gets a new mongo instance that has my blog
> > entry mapped by morphia for saving the whole POJO to mongo
> >                 setUpMongo();
> >                 blogDAO.save(blogEntry);
> >                 BlogEntryDetails details = new BlogEntryDetails(new
> > PageParameters().add("id", blogEntry.getObjectId().toString()));
> >                 setResponsePage(details);
> >             }
> >         });
> >
> >         LoadableDetachableModel ldm = new LoadableDetachableModel() {
> >             @Override
> >             protected Object load() {
> > //                TODO need to set athr only on new blogEntry
> >                 blogEntry.setAthr(CampingAwaitsSession.get().getUser());
> >                 return blogEntry;
> >             }
> >         };
> >
> >         form.add(new BlogEntryPanel("blogEntry", new
> > CompoundPropertyModel<Blog>(ldm)));
> >         add(form);
> >
> > }
> >
> > Any thoughts?  I feel like I understand the concept but the
> implementation
> > is throwing me.
> >
> > _______________________________________
> > Stephen Walsh | http://connectwithawalsh.com
> >
>
>
>
> --
> Martin Grigorov
> jWeekend
> Training, Consulting, Development
> http://jWeekend.com <http://jweekend.com/>
>

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