Skipping last duplicate with RxJava

Question

Suppose we have a subject that we use to publish some events

subject.onNext(...)

the end Subscriber is subscribed trough an Observable which was created from this subject...

I wonder if we can add some logic to observable so that if it gets the same value it wont propogate it to subscribers... or someting more complex..?

Is there a possibility to create an observable from subject that executes some code before emiting value to its subscribers?

Answer 1

There is a distinctUntilChanged operator that skips a value if it was emitted more than once in a row.

If you need more general behaviour and want to skip values based on some condition, then filter is probably what you are looking for.

Answer 2

Seems distictUntilChanged is exactly what is necessary in this case...

Answer 3

filter seems what i want but i dont really know how do i keep last value somewhere (unless i implement custom observable) and how do i access it to compare with new value?

You could use .buffer(2, 1).filter(...), so that filter has access to the current and to the last element.