Merge pull request ReactiveX#441 from zsxwing/issue-417

Fixed the issue that 'take' does not call 'onError'

Author: benjchristensen

rxjava-core/src/main/java/rx/operators/OperationTake.java

@@ -15,20 +15,30 @@
  */
 package rx.operators;
 
-import static org.junit.Assert.*;
-import static org.mockito.Matchers.*;
-import static org.mockito.Mockito.*;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyInt;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
 
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import org.junit.Test;
+import org.mockito.InOrder;
 
 import rx.Observable;
 import rx.Observable.OnSubscribeFunc;
 import rx.Observer;
 import rx.Subscription;
 import rx.subscriptions.Subscriptions;
+import rx.util.functions.Func1;
 
 /**
  * Returns an Observable that emits the first <code>num</code> items emitted by the source
@@ -114,30 +124,47 @@ private class ItemObserver implements Observer<T> {
             private final Observer<? super T> observer;
 
             private final AtomicInteger counter = new AtomicInteger();
+            private volatile boolean hasEmitedError = false;
 
             public ItemObserver(Observer<? super T> observer) {
                 this.observer = observer;
             }
 
             @Override
             public void onCompleted() {
+                if (hasEmitedError) {
+                    return;
+                }
                 if (counter.getAndSet(num) < num) {
                     observer.onCompleted();
                 }
             }
 
             @Override
             public void onError(Throwable e) {
+                if (hasEmitedError) {
+                    return;
+                }
                 if (counter.getAndSet(num) < num) {
                     observer.onError(e);
                 }
             }
 
             @Override
             public void onNext(T args) {
+                if (hasEmitedError) {
+                    return;
+                }
                 final int count = counter.incrementAndGet();
                 if (count <= num) {
-                    observer.onNext(args);
+                    try {
+                        observer.onNext(args);
+                    } catch (Throwable ex) {
+                        hasEmitedError = true;
+                        observer.onError(ex);
+                        subscription.unsubscribe();
+                        return;
+                    }
                     if (count == num) {
                         observer.onCompleted();
                     }
@@ -184,6 +211,47 @@ public void testTake2() {
             verify(aObserver, times(1)).onCompleted();
         }
 
+        @Test(expected = IllegalArgumentException.class)
+        public void testTakeWithError() {
+            Observable.from(1, 2, 3).take(1).map(new Func1<Integer, Integer>() {
+                public Integer call(Integer t1) {
+                    throw new IllegalArgumentException("some error");
+                }
+            }).toBlockingObservable().single();
+        }
+
+        @Test
+        public void testTakeWithErrorHappeningInOnNext() {
+            Observable<Integer> w = Observable.from(1, 2, 3).take(2).map(new Func1<Integer, Integer>() {
+                public Integer call(Integer t1) {
+                    throw new IllegalArgumentException("some error");
+                }
+            });
+
+            @SuppressWarnings("unchecked")
+            Observer<Integer> observer = mock(Observer.class);
+            w.subscribe(observer);
+            InOrder inOrder = inOrder(observer);
+            inOrder.verify(observer, times(1)).onError(any(IllegalArgumentException.class));
+            inOrder.verifyNoMoreInteractions();
+        }
+
+        @Test
+        public void testTakeWithErrorHappeningInTheLastOnNext() {
+            Observable<Integer> w = Observable.from(1, 2, 3).take(1).map(new Func1<Integer, Integer>() {
+                public Integer call(Integer t1) {
+                    throw new IllegalArgumentException("some error");
+                }
+            });
+
+            @SuppressWarnings("unchecked")
+            Observer<Integer> observer = mock(Observer.class);
+            w.subscribe(observer);
+            InOrder inOrder = inOrder(observer);
+            inOrder.verify(observer, times(1)).onError(any(IllegalArgumentException.class));
+            inOrder.verifyNoMoreInteractions();
+        }
+
         @Test
         public void testTakeDoesntLeakErrors() {
             Observable<String> source = Observable.create(new OnSubscribeFunc<String>()