<@U0BRK9HC5> Are you sure you can't `map` the `Beh...

# rx

[locke]

@gildor Are you sure you can't map the BehaviorSubject? Not trying to argue, but the above does allow values to be pushed into it? I'm not quite sure what you mean by the alternative solution.

The general goal is to have this Subject observer listen to values of this List, and emit filtered versions of the List. New to Rx, so maybe I have the structure of the way this should work setup incorrectly. It was my understanding that Subjects act as both Observer and Observable.

[gildor]

Of course you can map Behavior subject, but result of this mapping will be Observable, not a different behavior subject.
Do you understand why you current solution is wrong? You just do nothing with mapped subject.
Try to fix it and you will get what I mean.
You can map, but you must cache both objects: subject and mapped Observable
I understand what do you want to achieve, your code in second case just wrong because you don't use result of invocation

[gildor]

Alternative solution: filter lists before pushing them to subject instead of mapping them later

[locke]

I understand what you're saying, but it seems like the easy solution is to just do this:

val observable: Observable<List<Int>> by lazy {
        filterSubject.map{
            it -> it.filter(filter)
        }
    }

And now we're retaining the Observable, not creating more than one, and still accomplishing the goal.

[gildor]

Yes, yes, you right, just cache both, subject and Observable

[myanmarking]

you should make it a function, and return a new instance everytime you want observe something

[myanmarking]

like this:

override fun observeBandConnState(emmitFirst: Boolean): Observable<Boolean> {
        return protocolCallbackImpl.bandConnState
            .startWith(emmitFirst, isAvailable)
            .distinctUntilChanged()
            .observeOn(AndroidSchedulers.mainThread())
    }

[myanmarking]

bandConnState is a Subject