You could consider writing a provider method for those classes where you want
to use the non-default binding.
For example, assuming you use constructor injection:
public void configure()
{
bind( IFoo.class ).to( DefaultFoo.class );
}
@Provides
public E provideE( MyEFoo foo, IBar bar, ...etc... )
{
return new E( foo, bar, ...etc... );
}
@Provides
public K provideK( MyKFoo foo, IBar bar, ...etc... )
{
return new K( foo, bar, ...etc... );
}
The downside of this approach is that because you're constructing the instance,
it can't be intercepted by Guice (ie. for AOP).
Full example below...
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
import javax.inject.Inject;
import com.google.inject.AbstractModule;
import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.Provides;
interface IFoo
{
}
interface IBar
{
}
class DefaultFoo
implements IFoo
{
}
class DefaultBar
implements IBar
{
}
class MyBFoo
implements IFoo
{
}
class A
{
@Inject
public A( IFoo foo, IBar bar )
{
System.out.println( "Got " + foo + " and " + bar );
}
}
class B
{
@Inject
public B( IFoo foo, IBar bar )
{
System.out.println( "Got " + foo + " and " + bar );
}
}
class C
{
@Inject
public C( IFoo foo, IBar bar )
{
System.out.println( "Got " + foo + " and " + bar );
}
}
class ExampleModule
extends AbstractModule
{
@Override
protected void configure()
{
bind( IFoo.class ).to( DefaultFoo.class );
bind( IBar.class ).to( DefaultBar.class );
}
@Provides
B provideB( MyBFoo foo, IBar bar )
{
return new B( foo, bar );
}
}
public class Example
{
public static void main( String[] args )
{
Injector injector = Guice.createInjector( new ExampleModule() );
System.out.println( "--- A ---" );
injector.getInstance( A.class );
System.out.println( "--- B ---" );
injector.getInstance( B.class );
System.out.println( "--- C ---" );
injector.getInstance( C.class );
}
}
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
On 7 Sep 2012, at 08:02, robertdup wrote:
> Yes it's right.. but this way don't satisfy me totally cause I have some XFoo
> classes.
> I will have to create many annotation (@A,@B, ..., @Z), and I must bind all
> of them or I will get a guice exception.
>
> bind(IFoo.class).annotatedWith.(A.class).to(DefaultFoo.class);
> bind(IFoo.class).annotatedWith.(B.class).to(DefaultFoo.class);
> [...]
> bind(IFoo.class).annotatedWith.(Y.class).to(DefaultFoo.class);
> bind(IFoo.class).annotatedWith.(Z.class).to(DefaultFoo.class);
>
> In my case, I just have to override a couple of binding and let the other on
> the default implementation (DefaultFoo.class)
> bind(IFoo.class).annotatedWith.(E.class).to(MyEFoo.class);
> bind(IFoo.class).annotatedWith.(K.class).to(MyKFoo.class);
>
> Otherwise, PrivateModule looks too "heavy" to implement in my case..
>
> Well, Is there an other way that could be less verbose ?
>
> Best regards;
>
> On Friday, September 7, 2012 3:59:12 AM UTC+2, Fred Faber wrote:
> Strictly speaking, the robot legs problem describes a scenario where the
> types of your object chain are identical. In your case, you wouldn't have
> AFoo and BFoo, but just Foo. It's a luxury of sorts to have AFoo and BFoo
> because you _can_ use a binding annotation on the constructor of each. That
> is the solution I would prefer for its clarity in how AFoo and BFoo are being
> configured:
>
> class AFoo {
> @Inject AFoo(@DoesStuffRelatedToA IFoo ifoo) { ... }
> }
>
> class BFoo {
> @Inject BFoo(@DoesStuffRelatedToB IFoo ifoo) { ... }
> }
>
> Here, grepping through the code directly for DoesStuffRelatedToA would lead
> me to the binding for IFoo in context of AFoo, and that's a little bit of a
> win for code maintenance.
>
> Fred
>
> On Thu, Sep 6, 2012 at 12:51 PM, robertdup <[email protected]> wrote:
> Thanks for your reply.
>
> Do you know if it's a common uses to have more than 20 privates modules ?
>
>
>
> On Thursday, September 6, 2012 4:00:35 PM UTC+2, Thomas Broyer wrote:
> This is known as the "robot legs" problem, see
> http://code.google.com/p/google-guice/wiki/FrequentlyAskedQuestions#How_do_I_build_two_similar_but_slightly_different_trees_of_objec
>
> On Thursday, September 6, 2012 9:14:24 AM UTC+2, robertdup wrote:
> Hello there,
>
> I trying to implement default binding on my module without any success...
>
> Here is what I would like to do (my dream) :
>
> class AFoo
> {
> @Inject AFoo( IFoo foo ){}
> }
>
> class BFoo
> {
> @Inject BFoo( IFoo foo ){}
> }
>
>
> bind(IFoo.class).to(DefaultFoo.class);
> bind(IFoo.class).to(OtherFoo.class).on(BFoo.class);
>
>
> I know that I could solve this problem using annotation like this :
>
> class AFoo
> {
> @Inject AFoo( @A IFoo foo ){}
> }
>
> class BFoo
> {
> @Inject BFoo( @B IFoo foo ){}
> }
>
>
> bind(IFoo.class).annotatedWith(A.class).to(DefaultFoo.class);
> bind(IFoo.class).annotatedWith(B.class).to(OtherFoo.class);
>
> But this way is too boring and dirty.. (because I have to add
> annotation/binding definition for each one)
>
> Are there some others ways to solve Default binding "problem" ?
> Thanks in advance; Best regards
>
>
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