Question

I have code that looks like the ff.:

Interface i;
if (someCondition) {
  ImplementationA a = new ImplementationA();
  a.setFieldA(someValueA);
  a.setFieldB(someValueB);
  i = a;
} else {
  ImplementationB b = new ImplementationB();
  b.setFieldC(someValueC);
  i = b;
}
// Do something with i.

My questions are:

1. Should I use dependency injection here or is this beyond the scope of the technique?
2. If I should use dependency injection here, how can I accomplish it using Google Guice?

Answer 1

dynamic runtime injection is out of scope. you will have to configure which implementation to use via Modules. You could still use a factory (have a look at multibindings and assisted injection) and save yourself the work to set up your instances though …