Merge pull request eugenp#10701 from singhkaushal01/master

BAEL-4885: How to convert Mono<List<T>> into Flux<T>

reactor-core/src/test/java/com/baeldung/mono/MonoUnitTest.java

@@ -1,10 +1,14 @@
 package com.baeldung.mono;
 
 import org.junit.Test;
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
+import reactor.test.StepVerifier;
 
 import java.time.Duration;
 import java.time.temporal.ChronoUnit;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Optional;
 
 import static org.junit.Assert.assertEquals;
@@ -40,4 +44,40 @@ private Mono<String> blockingHelloWorld() {
         // blocking
         return Mono.just("Hello world!");
     }
+
+    @Test
+    public void whenMonoProducesListOfElements_thenConvertToFluxofElements() {
+
+        Mono<List<String>> monoList = monoOfList();
+
+        StepVerifier.create(monoTofluxUsingFlatMapIterable(monoList))
+                .expectNext("one", "two", "three", "four")
+                .verifyComplete();
+
+        StepVerifier.create(monoTofluxUsingFlatMapMany(monoList))
+                .expectNext("one", "two", "three", "four")
+                .verifyComplete();
+    }
+
+    private <T> Flux<T> monoTofluxUsingFlatMapIterable(Mono<List<T>> monoList) {
+        return monoList
+                .flatMapIterable(list -> list)
+                .log();
+    }
+
+    private <T> Flux<T> monoTofluxUsingFlatMapMany(Mono<List<T>> monoList) {
+        return monoList
+                .flatMapMany(Flux::fromIterable)
+                .log();
+    }
+
+    private Mono<List<String>> monoOfList() {
+        List<String> list = new ArrayList<>();
+        list.add("one");
+        list.add("two");
+        list.add("three");
+        list.add("four");
+
+        return Mono.just(list);
+    }
 }