RxJava - Connectable Operators

Following are the operators which has more precisely control over subscription.

Sr.No.	Operator & Description
1	Connect Instruct a connectable Observable to emit items to its subscribers.
2	Publish Converts an Observable to connectable Observable.
3	RefCount Converts a connectable Observable to ordinary Observable.
4	Replay Ensure same sequence of emitted items to be seen by each subscriber, even after the Observable has begun emitting items and subscribers subscribe later.

Connectable Operator Example

Create the following Java program using any editor of your choice in, say, C:\> RxJava.

ObservableTester.java

import io.reactivex.Observable;
import io.reactivex.observables.ConnectableObservable;
//Using connect operator on a ConnectableObservable
public class ObservableTester {
   public static void main(String[] args) {
      String[] letters = {"a", "b", "c", "d", "e", "f", "g"};
      final StringBuilder result = new StringBuilder();
      ConnectableObservable<String> connectable = Observable.fromArray(letters).publish();      
      connectable.subscribe(letter -> result.append(letter));
      System.out.println(result.length());
      connectable.connect();
      System.out.println(result.length());
      System.out.println(result);
   }
}

Verify the Result

Compile the class using javac compiler as follows −

C:\RxJava>javac ObservableTester.java

Now run the ObservableTester as follows −

C:\RxJava>java ObservableTester

It should produce the following output −

0
7
abcdefg