2008/10/2 Grace <[EMAIL PROTECTED]>
>
> Hi Rodrigo,
>
> I did some more testing.
>
> 1) If Stage is Stage.PRODUCTION, the Provider's get() method actually
> gets called
> when Guice.createInjector(Stage.PRODUCTION, ...) is called.
>
> binder.bind(TestClass.class).toProvider(new Provider<TestClass>() {
> public TestClass get() {
> return new TestClass();
> }
> }).in(Scopes.SINGLETON);
>
> private static TestClass
> {
> TestClass() { // let's say construction takes a long
> time... };
> }
>
>
> So, if TestClass() takes a long time to construct, then
> Guice.createInjector(..) will take a long time to return.
>
> 2) Suppose the setup is the same as case 1 except now I remove the
> Singleton scope, Provider's get() does not get called when
> Guice.createInjector(..) is called. Hence, the createInjector(..)
> method returns quickly.
>
> 3) createInjector(..) also returns quickly when Stage is DEVELOPMENT.
> Provider's get() also does not get called.
>
> So, my question is, why does 1) behave the way it does? Why does the
> Provider's get() gets called when
> Guice.createInjector(Stage.PRODUCTION, ...) is called? I understand
> that the Provider's constructor will be called but why the get()
> method also?
>
FYI, the difference between Stage.PRODUCTION and
Stage.DEVELOPMENT is mentioned in the User Guide:
*"Development Stages
[...snip...]
During development, Guice will load singleton objects on demand.
This way, your application starts up fast and only loads the parts you're
testing.
In production, Guice will load all your singleton objects at startup.
This helps catch errors early and takes any performance hits up front."
*
so 1) takes a long time because singleton + production = get() called at
startup
I would think that the Provider's get() gets called when I actually
> invoke it. When I put Scopes.SINGLETON, I thought it
> means that the Provider is a singleton. Am I correct?
>
> Thanks, Grace
>
>
>
> On Oct 1, 9:30 am, "Rodrigo M. do Prado" <[EMAIL PROTECTED]>
> wrote:
> > Hi Grace,
> >
> > could you attach the entire source code of the provider that you've
> > implemented?
> >
> > Tks, Rodrigo
> >
> >
> >
> > On Wed, Oct 1, 2008 at 12:36 AM, Grace <[EMAIL PROTECTED]> wrote:
> >
> > > Hi all,
> >
> > > It takes less than 1/2 sec to create the injector when I only have
> > > bindings from interfaces to regular classes.
> >
> > > But once I bind provider,
> >
> > > public class VehicleProvider implements Provider<IVehicle>{
> >
> > > }
> >
> > >
> binder.bind(IVehicle.class).toProvider(VehicleProvider.class).in(Scopes.SINGLETON),
> >
> > > it takes more than 10 secs to create the injector.
> > > How come there is such great difference? If I care about speed,
> > > should I avoid using provider?
> >
> > > Thanks, Grace
> >
> > --
> > Rodrigo M. do Prado
> > [EMAIL PROTECTED]
> >
--
Cheers, Stuart
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