Observables

Operators

Subjects

Schedulers

Miscellaneous

RxJava Useful Resources

RxJava - Utility Operators

Quiz

Following are the operators which are often useful with Observables.

Sr.No.	Operator & Description
1	delay Register action to handle Observable life-cycle events.
2	materialize/dematerialize Represents item emitted and notification sent.
3	observeOn Specify the scheduler to be observed.
4	serialize Force Observable to make serialized calls.
5	subscribe Operate upon the emissions of items and notifications like complete from an Observable
6	subscribeOn Specify the scheduler to be used by an Observable when it is subscribed to.
7	timeInterval Convert an Observable to emit indications of the amount of time elapsed between emissions.
8	timeout Issues error notification if specified time occurs without emitting any item.
9	timestamp Attach timestamp to each item emitted.
9	using Creates a disposable resource or same lifespan as that of Observable.

Example - Usage of subscribe operator

ObservableTester.java

package com.tutorialspoint;

import io.reactivex.rxjava3.core.Observable;

//Using subscribe operator to subscribe to an Observable
public class ObservableTester {
   public static void main(String[] args) {    
	   String[] letters = {"a", "b", "c", "d", "e", "f", "g"};
       final StringBuilder result = new StringBuilder();
       Observable<String> observable = Observable.fromArray(letters);
       observable.subscribe( letter -> result.append(letter));
       System.out.println(result);
   }
}

Output

Compile and Run the code to verify the following output −

abcdefg

Example - Usage of timestamp operator

package com.tutorialspoint;

import io.reactivex.rxjava3.core.Observable;

//Using subscribe operator to subscribe to an Observable
public class ObservableTester {
   public static void main(String[] args) {    
      String[] letters = {"a", "b", "c", "d", "e", "f", "g"};
      final StringBuilder result = new StringBuilder();
      Observable<String> observable = Observable.fromArray(letters);
      observable
         .timestamp()
         .subscribe( letter -> result.append(letter + "\n"));
      System.out.println(result);
   }
}

Output

Compile and Run the code to verify the following output −

Timed[time=1758342979382, unit=MILLISECONDS, value=a]
Timed[time=1758342979386, unit=MILLISECONDS, value=b]
Timed[time=1758342979386, unit=MILLISECONDS, value=c]
Timed[time=1758342979386, unit=MILLISECONDS, value=d]
Timed[time=1758342979386, unit=MILLISECONDS, value=e]
Timed[time=1758342979386, unit=MILLISECONDS, value=f]
Timed[time=1758342979386, unit=MILLISECONDS, value=g]

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