java - Infinite observable from another observable -

i have observable represents sequence selected db table, finite.

observable<item> selectresults() { ... } 

i implement pulling specified interval, @ end end observable wrap original 1 , pull indefinitely.

i don't know how :(

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ok, idea do, modeled around interval observable, needs error handling , unsubscribe logic.

public class onsubscribeperiodicobservable implements onsubscribe<item> { ...    @override   public void call(final subscriber<? super item> subscriber) {       final worker worker = scheduler.createworker();       subscriber.add( worker );        worker.scheduleperiodically(new action0() {           @override           public void call() {     selectresults().subscribe( new observer<item>() {             @override             public void oncompleted() {               //continue             }              @override             public void onerror(throwable e) {               subscriber.onerror( e );             }              @override             public void onnext(item t) {               subscriber.onnext( t );             }          });            }        }, initialdelay, period, unit); } 

you can accomplish standard operators give error propagation, unsubscription , backpressure cheap:

observable<integer> databasequery = observable     .just(1, 2, 3, 4)     .delay(500, timeunit.milliseconds);  observable<integer> result = observable         .timer(1, 2, timeunit.seconds)         .onbackpressuredrop()         .concatmap(t -> databasequery);  result.subscribe(system.out::println);  thread.sleep(10000);