RxJava Nested Observables exposing values

Question

I have the following code which works as expected. However, I do not like having a blockingGet. Is there a way to move the getSingle() call higher up into a 'global' variable of the Observable to avoid this? In other words I'd like getSingle to complete without using blockingGet before moving on in the code. Note that in the map call I need access to the foos, bar and getSingle() response.

Any help would be appreciated!

public List<Baz> example(Single<Collection<Foo>> foosSingle, Collection<Bar> bars) {
  return foosSingle
    .flatMap(foos -> 
      Observable.fromIterable(bars)
        .map(bar -> getBaz(foos, getSingle(bar.getBlah()).blockingGet(), bar.getFlaz())
        .toList()
    );
}

FWIW I tried replacing the .map call with something like this:

 .map(bar -> Lists.ArrayList(bar, getSingle(bar.getBlah()).blockingGet())
 .map(list -> getBaz(foos, list.get(1), list.get(0).getFlaz())

which gives me access to all variables I need, but it doesn't resolve the blockingGet issue.

Answer 1

Use .flatMap instead of map

public List<Baz> example(Single<Collection<Foo>> foosSingle, final Collection<Bar> bars) {
  return foosSingle
    .flatMap(foos -> 
      Observable.fromIterable(bars)
        .flatMapSingle(bar -> {
          return getSingle(bar.getBlah())
            .map(x -> getBaz(foos, x, bar.getFlaz()))
        })
        .toList()
    );
}