How does RoboGuice know what i mean to inject?

Question

I am using RoboGuice 4.0beta2 , and i have this problem

I have several different objects that implement the same interface

call them A implements ITest B implements ITest C implements ITest

I have class D, that uses all 3 implementations together, each has a different purpose, but the same API for that

Inside class D i would like to inject A,B, and C, which have nothing to do with eachother,except the fact that they all implement the same interface

How would i configure the Module class to know that i mean different implementatios of ITest ?

Are you injecting A, B and C by their types or under the ITest type? — John Ericksen, Jan 15 '14 at 18:42

John Ericksen · Answer 1 · 2014-01-16T05:53:24.023

Assuming you have the following configuration:

class D{
    @Inject ITest a;
    @Inject ITest b;
    @Inject ITest c;
}

you can set up your module like the following so you can inject the different types by @Name:

public class ABCModule extends AbstractModule {

    @Override
    protected void configure() {
        bind(ITest.class).annotatedWith(Names.named("a")).to(A.class);
        bind(ITest.class).annotatedWith(Names.named("b")).to(B.class);
        bind(ITest.class).annotatedWith(Names.named("c")).to(C.class);
    }
}

which allows you to inject the different types like so:

class D{
    @Inject @Named("a") ITest a;
    @Inject @Named("b") ITest b;
    @Inject @Named("c") ITest c;
}

How does RoboGuice know what i mean to inject?

1 Answers1