Adding bindings to multibinder from multiple private modules

[mmadson]

It looks like this is a known limitation and I was looking for an outstanding issue to see if work was being done to try and address it. I'd like to be able to do the following:

public final class MyAppModule extends AbstractModule {
    @Override
    protected void configure() {
        install(new FooPrivateModule());
        install(new BarPrivateModule());
    }
}

public final class FooPrivateModule extends PrivateModule {
    @Override
    protected void configure() {
        Multibinder<Thing> thingBinder = Multibinder.newSetBinder(binder(), Thing.class);
        thingBinder.addBinding().to(FooThing.class);
        expose(new TypeLiteral<Set<Thing>>() {});
    }
}

public final class BarPrivateModule extends PrivateModule {
    @Override
    protected void configure() {
        Multibinder<Thing> thingBinder = Multibinder.newSetBinder(binder(), Thing.class);
        thingBinder.addBinding().to(BarThing.class);
        expose(new TypeLiteral<Set<Thing>>() {});
    }
}

Set<Thing> things = Guice.createInjector(new MyAppModule()).getInstance(Key.get(new TypeLiteral<Set<Thing>>() {}));

// things would contain FooThing bound and exposed in FooPrivateModule and BarThing bound and exposed in BarPrivateModule

Thanks!

[sameb]

There unfortunately is no way to do this today, nor are there any plans to make it work. If you'd like to try to add support, we'll gladly accept pull requests. :-)

[bcmedeiros]

https://groups.google.com/forum/#!topic/google-guice/h70a9pwD6_g workaround is not enough for you?

[JLLeitschuh]

My workaround (using Kotlin) was to create two modules and then merge them.

fun createModule() : Module {
    val basePrivateModule = module {
        // Private/exposed stuff here
    }

    val nonPrivateModule = module {
        /*
         * Multi-binders do not support spanning private modules.
         * See: https://github.com/google/guice/issues/906
         */
        KotlinMultibinder
            .newSetBinder<Set<Whatever>>(binder())
            .addBinding()
            .to(key<WhateverImpl>())
    }

    return module {
        // Create a module that merges the private and the non-private
        install(basePrivateModule)
        install(nonPrivateModule)
    }
}

This API uses: https://github.com/JLLeitschuh/kotlin-guiced