Learning RxJava - Second Edition

cast()

cast() is a simple, map-like operator that casts each emitted item to another type. If we need to cast each value emitted by Observable<String> to an Object (and return an Observable<Object>), we could use the map() operator as shown in the following example:

Observable<Object> items = Observable.just("Alpha", "Beta", "Gamma")                                     .map(s -> (Object) s);

Instead, we can use the more specialized shorthand cast(), and simply pass the class type we want to cast to, as shown in this code snippet:

Observable<Object> items = Observable.just("Alpha", "Beta", "Gamma")                                     .cast(Object.class);

If you find that you are having typing issues due to inherited or polymorphic types being mixed, this is an effective brute-force way to cast everything down ...