injector.getInstance of a generic type

Question

I have seen this post about registering generic type.

example on how to register:

 bind(new TypeLiteral<Dal<RoutingResponse>>() {}).to((Class<? extends Dal<RoutingResponse>>) ResponseDal.class);

however how can I get an instance of a generic type from the injector?

I have tried:

injector.getInstance(Dal<RoutingResponse>().getClass());

but got compilation error.

How should I write this?

I'm actually not sure if it's a duplicate as I don't see a relationship between both snippets you've posted. Does this help? http://stackoverflow.com/questions/2581137/injecting-generics-with-guice?rq=1 — Sotirios Delimanolis, Feb 16 '15 at 22:14

score 17 · Accepted Answer · edited Feb 04 '17 at 09:36

17

You can use Key to get instances of these bindings:

injector.getInstance(new Key<Dal<RoutingResponse>>() {}); // supplied by @DanielPryden in the comments

or in a longer version, with a TypeLiteral:

injector.getInstance(Key.get(new TypeLiteral<Dal<RoutingResponse>>() {}));

edited Feb 04 '17 at 09:36

Bombe

answered Feb 16 '15 at 23:11

condit

1

Or just use `Key` directly: `new Key>() {}` will do the same thing and is shorter. – Daniel Pryden Feb 19 '15 at 20:43
Hi I am trying to do something similar, but my generic class has another dep which is injected. For now I have to fetch the dependency and put it in the constructor, is there a way to avoid that? Code example - `Dep dep = injector.getInstance(Dep.class); injector.getInstance(Key.get(new TypeLiteral>(dep) {}));` can I simply write it like `injector.getInstance(Key.get(new TypeLiteral>(dep) {}));` and let guice handle the DI of dep? – Manthan Jamdagni Apr 08 '19 at 12:04

1 Answers1