RxJava – Single Observable
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The Single class represents the single value response. Single observable can only emit either a single successful value or an error. It does not emit onComplete event.
Class Declaration
Following is the declaration for io.reactivex.Single<T> class −
public abstract class Single<T> extends Object implements SingleSource<T>
Protocol
Following is the sequential protocol that Single Observable operates −
onSubscribe (onSuccess | onError)?
Single Example
Create the following Java program using any editor of your choice in, say, C:> RxJava.
ObservableTester.java
import java.util.concurrent.TimeUnit; import io.reactivex.Single; import io.reactivex.disposables.Disposable; import io.reactivex.observers.DisposableSingleObserver; import io.reactivex.schedulers.Schedulers; public class ObservableTester { public static void main(String[] args) throws InterruptedException { //Create the observable Single<String> testSingle = Single.just("Hello World"); //Create an observer Disposable disposable = testSingle .delay(2, TimeUnit.SECONDS, Schedulers.io()) .subscribeWith( new DisposableSingleObserver<String>() { @Override public void onError(Throwable e) { e.printStackTrace(); } @Override public void onSuccess(String value) { System.out.println(value); } }); Thread.sleep(3000); //start observing disposable.dispose(); } }
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 −
Hello World
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