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Following are the operators which are used to create an Observable.
| Sr.No. | Operator & Description |
|---|---|
| 1 |
Create Creates an Observable from scratch and allows observer method to call programmatically. |
| 2 |
Defer Do not create an Observable until an observer subscribes. Creates a fresh observable for each observer. |
| 3 |
Empty/Never/Throw Creates an Observable with limited behavior. |
| 4 |
From Converts an object/data structure into an Observable. |
| 5 |
Interval Creates an Observable emitting integers in sequence with a gap of specified time interval. |
| 6 |
Just Converts an object/data structure into an Observable to emit the same or same type of objects. |
| 7 |
Range Creates an Observable emitting integers in sequence of given range. |
| 8 |
Repeat Creates an Observable emitting integers in sequence repeatedly. |
| 9 |
Start Creates an Observable to emit the return value of a function. |
| 10 |
Timer Creates an Observable to emit a single item after given delay. |
Creating Operator Example
Create the following Java program using any editor of your choice in, say, C:> RxJava.
ObservableTester.java
import io.reactivex.Observable;
//Using fromArray operator to create 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
.map(String::toUpperCase)
.subscribe( letter -> result.append(letter));
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 −
ABCDEFG
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