BAEL - 1511

rxjava-2/pom.xml

@@ -34,6 +34,13 @@
             <artifactId>rxrelay</artifactId>
             <version>${rxrelay.version}</version>
         </dependency>
+        <!-- https://mvnrepository.com/artifact/com.github.akarnokd/rxjava2-extensions -->
+<dependency>
+    <groupId>com.github.akarnokd</groupId>
+    <artifactId>rxjava2-extensions</artifactId>
+    <version>${rxjava2.ext.version}</version>
+</dependency>
+        
     </dependencies>
 
     <properties>
@@ -41,5 +48,6 @@
         <rx.java2.version>2.2.2</rx.java2.version>
         <awaitility.version>1.7.0</awaitility.version>
         <rxrelay.version>2.0.0</rxrelay.version>
+        <rxjava2.ext.version>0.20.4</rxjava2.ext.version>
     </properties>
 </project>

rxjava-2/src/test/java/com/baeldung/rxjava/AsyncAndSyncToObservableIntegrationTest.java

@@ -0,0 +1,103 @@
+package com.baeldung.rxjava;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.junit.Test;
+
+import hu.akarnokd.rxjava2.async.AsyncObservable;
+import io.reactivex.Observable;
+
+public class AsyncAndSyncToObservableIntegrationTest {
+
+    AtomicInteger counter = new AtomicInteger();
+    Callable<Integer> callable = () -> counter.incrementAndGet();
+
+    @Test
+    public void givenSyncMethod_whenConvertedWithFromCallable_thenReturnObservable() {// method will execute every time it gets subscribed
+
+        Observable<Integer> source = Observable.fromCallable(callable);
+
+        for (int i = 1; i < 5; i++) {
+            source.test()
+                .awaitDone(5, TimeUnit.SECONDS)
+                .assertResult(i);
+
+            assertEquals(i, counter.get());
+        }
+    }
+
+    @Test
+    public void givenSyncMethod_whenConvertedWithStart_thenReturnObservable() {// method will execute only once and cache its result.
+
+        Observable<Integer> source = AsyncObservable.start(callable);
+
+        for (int i = 1; i < 5; i++) {
+            source.test()
+                .awaitDone(5, TimeUnit.SECONDS)
+                .assertResult(1);
+
+            assertEquals(1, counter.get());
+        }
+    }
+
+    @Test
+    public void givenAsyncMethod_whenConvertedWithFromFuture_thenRetrunObservble() { // method will execute only once and cache its result.
+
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+        Future<Integer> future = executor.submit(callable);
+        Observable<Integer> source = Observable.fromFuture(future);
+
+        for (int i = 1; i < 5; i++) {
+            source.test()
+                .awaitDone(5, TimeUnit.SECONDS)
+                .assertResult(1);
+
+            assertEquals(1, counter.get());
+        }
+
+        executor.shutdown();
+    }
+
+    @Test
+    public void givenAsyncMethod_whenConvertedWithStartFuture_thenRetrunObservble() {// method will execute every time it gets subscribed
+
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+        Observable<Integer> source = AsyncObservable.startFuture(() -> executor.submit(callable));
+
+        for (int i = 1; i < 5; i++) {
+            source.test()
+                .awaitDone(5, TimeUnit.SECONDS)
+                .assertResult(i);
+
+            assertEquals(i, counter.get());
+        }
+
+        executor.shutdown();
+    }
+
+    @Test
+    public void givenAsyncMethod_whenConvertedWithDeferFuture_thenRetrunObservble() { // method will execute only once and cache its result.
+
+        List<Integer> list = Arrays.asList(new Integer[] { counter.incrementAndGet(), counter.incrementAndGet(), counter.incrementAndGet() });
+        ExecutorService exec = Executors.newSingleThreadExecutor();
+        Callable<Observable<Integer>> callable = () -> Observable.fromIterable(list);
+        Observable<Integer> source = AsyncObservable.deferFuture(() -> exec.submit(callable));
+        for (int i = 1; i < 4; i++) {
+            source.test()
+                .awaitDone(5, TimeUnit.SECONDS)
+                .assertResult(1, 2, 3);
+        }
+
+        exec.shutdown();
+    }
+
+}