OperatorOnErrorReturn

rxjava-core/src/main/java/rx/Observable.java

@@ -58,7 +58,6 @@
 import rx.operators.OperationMergeMaxConcurrent;
 import rx.operators.OperationMulticast;
 import rx.operators.OperationOnErrorResumeNextViaObservable;
-import rx.operators.OperationOnErrorReturn;
 import rx.operators.OperationOnExceptionResumeNextViaObservable;
 import rx.operators.OperationParallelMerge;
 import rx.operators.OperationReplay;
@@ -108,6 +107,7 @@
 import rx.operators.OperatorObserveOn;
 import rx.operators.OperatorOnErrorFlatMap;
 import rx.operators.OperatorOnErrorResumeNextViaFunction;
+import rx.operators.OperatorOnErrorReturn;
 import rx.operators.OperatorParallel;
 import rx.operators.OperatorPivot;
 import rx.operators.OperatorRepeat;
@@ -4547,7 +4547,7 @@ public final Observable<T> onErrorResumeNext(final Observable<? extends T> resum
      * @see <a href="https://github.com/Netflix/RxJava/wiki/Error-Handling-Operators#wiki-onerrorreturn">RxJava Wiki: onErrorReturn()</a>
      */
     public final Observable<T> onErrorReturn(Func1<Throwable, ? extends T> resumeFunction) {
-        return create(OperationOnErrorReturn.onErrorReturn(this, resumeFunction));
+        return lift(new OperatorOnErrorReturn<T>(resumeFunction));
     }
 
     /**

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

@@ -0,0 +1,79 @@
+/**
+ * Copyright 2014 Netflix, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package rx.operators;
+
+import java.util.Arrays;
+import rx.Observable.Operator;
+import rx.Subscriber;
+import rx.exceptions.CompositeException;
+import rx.functions.Func1;
+
+/**
+ * Instruct an Observable to emit a particular item to its Observer's <code>onNext</code> method
+ * rather than invoking <code>onError</code> if it encounters an error.
+ * <p>
+ * <img width="640" src="https://github.com/Netflix/RxJava/wiki/images/rx-operators/onErrorReturn.png">
+ * <p>
+ * By default, when an Observable encounters an error that prevents it from emitting the expected
+ * item to its Observer, the Observable invokes its Observer's <code>onError</code> method, and then
+ * quits without invoking any more of its Observer's methods. The onErrorReturn operation changes
+ * this behavior. If you pass a function (resumeFunction) to onErrorReturn, if the original
+ * Observable encounters an error, instead of invoking its Observer's <code>onError</code> method,
+ * it will instead pass the return value of resumeFunction to the Observer's <code>onNext</code>
+ * method.
+ * <p>
+ * You can use this to prevent errors from propagating or to supply fallback data should errors be
+ * encountered.
+ * 
+ * @param <T> the value type
+ */
+public final class OperatorOnErrorReturn<T> implements Operator<T, T> {
+    final Func1<Throwable, ? extends T> resultFunction;
+
+    public OperatorOnErrorReturn(Func1<Throwable, ? extends T> resultFunction) {
+        this.resultFunction = resultFunction;
+    }
+
+    @Override
+    public Subscriber<? super T> call(final Subscriber<? super T> child) {
+        return new Subscriber<T>(child) {
+
+            @Override
+            public void onNext(T t) {
+                child.onNext(t);
+            }
+
+            @Override
+            public void onError(Throwable e) {
+                try {
+                    T result = resultFunction.call(e);
+
+                    child.onNext(result);
+                } catch (Throwable x) {
+                    child.onError(new CompositeException(Arrays.asList(e, x)));
+                    return;
+                }
+                child.onCompleted();
+            }
+
+            @Override
+            public void onCompleted() {
+                child.onCompleted();
+            }
+
+        };
+    }
+}

rxjava-core/src/test/java/rx/operators/OperationOnErrorReturnTest.java → rxjava-core/src/test/java/rx/operators/OperatorOnErrorReturnTest.java

@@ -21,7 +21,6 @@
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
-import static rx.operators.OperationOnErrorReturn.onErrorReturn;
 
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -30,10 +29,11 @@
 
 import rx.Observable;
 import rx.Observer;
+import rx.Subscriber;
 import rx.Subscription;
 import rx.functions.Func1;
 
-public class OperationOnErrorReturnTest {
+public class OperatorOnErrorReturnTest {
 
     @Test
     public void testResumeNext() {
@@ -42,15 +42,15 @@ public void testResumeNext() {
         Observable<String> w = Observable.create(f);
         final AtomicReference<Throwable> capturedException = new AtomicReference<Throwable>();
 
-        Observable<String> observable = Observable.create(onErrorReturn(w, new Func1<Throwable, String>() {
+        Observable<String> observable = w.onErrorReturn(new Func1<Throwable, String>() {
 
             @Override
             public String call(Throwable e) {
                 capturedException.set(e);
                 return "failure";
             }
 
-        }));
+        });
 
         @SuppressWarnings("unchecked")
         Observer<String> observer = mock(Observer.class);
@@ -79,15 +79,15 @@ public void testFunctionThrowsError() {
         Observable<String> w = Observable.create(f);
         final AtomicReference<Throwable> capturedException = new AtomicReference<Throwable>();
 
-        Observable<String> observable = Observable.create(onErrorReturn(w, new Func1<Throwable, String>() {
+        Observable<String> observable = w.onErrorReturn(new Func1<Throwable, String>() {
 
             @Override
             public String call(Throwable e) {
                 capturedException.set(e);
                 throw new RuntimeException("exception from function");
             }
 
-        }));
+        });
 
         @SuppressWarnings("unchecked")
         Observer<String> observer = mock(Observer.class);
@@ -108,7 +108,7 @@ public String call(Throwable e) {
         assertNotNull(capturedException.get());
     }
 
-    private static class TestObservable implements Observable.OnSubscribeFunc<String> {
+    private static class TestObservable implements Observable.OnSubscribe<String> {
 
         final Subscription s;
         final String[] values;
@@ -120,7 +120,7 @@ public TestObservable(Subscription s, String... values) {
         }
 
         @Override
-        public Subscription onSubscribe(final Observer<? super String> observer) {
+        public void call(final Subscriber<? super String> subscriber) {
             System.out.println("TestObservable subscribed to ...");
             t = new Thread(new Runnable() {
 
@@ -130,19 +130,18 @@ public void run() {
                         System.out.println("running TestObservable thread");
                         for (String s : values) {
                             System.out.println("TestObservable onNext: " + s);
-                            observer.onNext(s);
+                            subscriber.onNext(s);
                         }
                         throw new RuntimeException("Forced Failure");
                     } catch (Throwable e) {
-                        observer.onError(e);
+                        subscriber.onError(e);
                     }
                 }
 
             });
             System.out.println("starting TestObservable thread");
             t.start();
             System.out.println("done starting TestObservable thread");
-            return s;
         }
     }
 }