Merge branch 'throttleLast' into throttle

Conflicts:
	rxjava-core/src/main/java/rx/Observable.java
	rxjava-core/src/main/java/rx/operators/OperationThrottle.java

Author: benjchristensen

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

@@ -66,6 +66,7 @@
 import rx.operators.OperationTakeWhile;
 import rx.operators.OperationThrottle;
 import rx.operators.OperationThrottleWithTimeout;
+import rx.operators.OperationThrottleLast;
 import rx.operators.OperationTimestamp;
 import rx.operators.OperationToObservableFuture;
 import rx.operators.OperationToObservableIterable;
@@ -1843,6 +1844,38 @@ public Observable<T> throttleWithTimeout(long timeout, TimeUnit unit) {
     public Observable<T> throttleWithTimeout(long timeout, TimeUnit unit, Scheduler scheduler) {
         return create(OperationThrottleWithTimeout.throttleWithTimeout(this, timeout, unit, scheduler));
     }
+    
+    
+    /**
+     * Throttles the {@link Observable} by dropping values which are followed by newer values before the timer has expired.
+     * 
+     * @param timeout
+     *            The time each value has to be 'the most recent' of the {@link Observable} to ensure that it's not dropped.
+     * 
+     * @param unit
+     *            The {@link TimeUnit} for the timeout.
+     * 
+     * @return An {@link Observable} which filters out values which are too quickly followed up with newer values.
+     */
+    public Observable<T> throttleLast(long timeout, TimeUnit unit) {
+        return create(OperationThrottleLast.throttleLast(this, timeout, unit));
+    }
+
+    /**
+     * Throttles the {@link Observable} by dropping values which are followed by newer values before the timer has expired.
+     * 
+     * @param timeout
+     *            The time each value has to be 'the most recent' of the {@link Observable} to ensure that it's not dropped.
+     * @param unit
+     *            The {@link TimeUnit} for the timeout.
+     * @param scheduler
+     *            The {@link Scheduler} to use when timing incoming values.
+     * @return An {@link Observable} which filters out values which are too quickly followed up with newer values.
+     */
+    public Observable<T> throttleLast(long timeout, TimeUnit unit, Scheduler scheduler) {
+        return create(OperationThrottleLast.throttleLast(this, timeout, unit, scheduler));
+    }
+    
 
     /**
      * Wraps each item emitted by a source Observable in a {@link Timestamped} object.
@@ -2301,6 +2334,7 @@ public static <T1, T2, T3, T4, T5, T6, T7, R> Observable<R> combineLatest(Observ
     }
 
     /**
+<<<<<<< HEAD
      * Throttles the {@link Observable} by dropping values which are followed by newer values before the timer has expired.
      * 
      * @param timeout    The time each value has to be 'the most recent' of the {@link Observable} to ensure that it's not dropped.
@@ -2324,6 +2358,8 @@ public Observable<T> throttle(long timeout, TimeUnit unit, Scheduler scheduler)
     }
 
     /**
+=======
+>>>>>>> throttleLast
      * @see #combineLatest(Observable, Observable, Func2)
      */
     public static <T1, T2, T3, T4, T5, T6, T7, T8, R> Observable<R> combineLatest(Observable<? extends T1> o1, Observable<? extends T2> o2, Observable<? extends T3> o3, Observable<? extends T4> o4, Observable<? extends T5> o5, Observable<? extends T6> o6, Observable<? extends T7> o7, Observable<? extends T8> o8,

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

@@ -0,0 +1,188 @@
+/**
+ * Copyright 2013 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 static org.mockito.Matchers.*;
+import static org.mockito.Mockito.*;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InOrder;
+
+import rx.Observable;
+import rx.Observable.OnSubscribeFunc;
+import rx.Observer;
+import rx.Scheduler;
+import rx.Subscription;
+import rx.concurrency.Schedulers;
+import rx.concurrency.TestScheduler;
+import rx.subscriptions.Subscriptions;
+import rx.util.functions.Action0;
+import rx.util.functions.Func1;
+
+/**
+ * This operation is used to filter out bursts of events. This is done by ignoring the events from an observable which are too
+ * quickly followed up with other values. Values which are not followed up by other values within the specified timeout are published
+ * as soon as the timeout expires.
+ */
+public final class OperationThrottleLast {
+
+    /**
+     * This operation filters out events which are published too quickly in succession. This is done by dropping events which are
+     * followed up by other events before a specified timer has expired. If the timer expires and no follow up event was published (yet)
+     * the last received event is published.
+     * 
+     * @param items
+     *            The {@link Observable} which is publishing events.
+     * @param timeout
+     *            How long each event has to be the 'last event' before it gets published.
+     * @param unit
+     *            The unit of time for the specified timeout.
+     * @return A {@link Func1} which performs the throttle operation.
+     */
+    public static <T> OnSubscribeFunc<T> throttleLast(Observable<T> items, long timeout, TimeUnit unit) {
+        return throttleLast(items, timeout, unit, Schedulers.threadPoolForComputation());
+    }
+
+    /**
+     * This operation filters out events which are published too quickly in succession. This is done by dropping events which are
+     * followed up by other events before a specified timer has expired. If the timer expires and no follow up event was published (yet)
+     * the last received event is published.
+     * 
+     * @param items
+     *            The {@link Observable} which is publishing events.
+     * @param timeout
+     *            How long each event has to be the 'last event' before it gets published.
+     * @param unit
+     *            The unit of time for the specified timeout.
+     * @param scheduler
+     *            The {@link Scheduler} to use internally to manage the timers which handle timeout for each event.
+     * @return A {@link Func1} which performs the throttle operation.
+     */
+    public static <T> OnSubscribeFunc<T> throttleLast(final Observable<T> items, final long timeout, final TimeUnit unit, final Scheduler scheduler) {
+        return new OnSubscribeFunc<T>() {
+            @Override
+            public Subscription onSubscribe(Observer<? super T> observer) {
+                return items.window(timeout, unit, scheduler).flatMap(new Func1<Observable<T>, Observable<T>>() {
+
+                    @Override
+                    public Observable<T> call(Observable<T> o) {
+                        return o.takeLast(1);
+                    }
+                }).subscribe(observer);
+            }
+        };
+    }
+
+    public static class UnitTest {
+
+        private TestScheduler scheduler;
+        private Observer<String> observer;
+
+        @Before
+        @SuppressWarnings("unchecked")
+        public void before() {
+            scheduler = new TestScheduler();
+            observer = mock(Observer.class);
+        }
+
+        @Test
+        public void testThrottlingWithCompleted() {
+            Observable<String> source = Observable.create(new OnSubscribeFunc<String>() {
+                @Override
+                public Subscription onSubscribe(Observer<? super String> observer) {
+                    publishNext(observer, 100, "one");    // Should be skipped since "two" will arrive before the timeout expires.
+                    publishNext(observer, 400, "two");    // Should be published since "three" will arrive after the timeout expires.
+                    publishNext(observer, 900, "three");   // Should be skipped since onCompleted will arrive before the timeout expires.
+                    publishCompleted(observer, 1000);     // Should be published as soon as the timeout expires.
+
+                    return Subscriptions.empty();
+                }
+            });
+
+            Observable<String> sampled = Observable.create(OperationThrottleLast.throttleLast(source, 400, TimeUnit.MILLISECONDS, scheduler));
+            sampled.subscribe(observer);
+
+            InOrder inOrder = inOrder(observer);
+
+            scheduler.advanceTimeTo(1000, TimeUnit.MILLISECONDS);
+            inOrder.verify(observer, times(1)).onNext("two");
+            inOrder.verify(observer, times(1)).onCompleted();
+            inOrder.verifyNoMoreInteractions();
+        }
+
+        @Test
+        public void testThrottlingWithError() {
+            Observable<String> source = Observable.create(new OnSubscribeFunc<String>() {
+                @Override
+                public Subscription onSubscribe(Observer<? super String> observer) {
+                    Exception error = new TestException();
+                    publishNext(observer, 100, "one");    // Should be published since "two" will arrive after the timeout expires.
+                    publishNext(observer, 600, "two");    // Should be skipped since onError will arrive before the timeout expires.
+                    publishError(observer, 700, error);   // Should be published as soon as the timeout expires.
+
+                    return Subscriptions.empty();
+                }
+            });
+
+            Observable<String> sampled = Observable.create(OperationThrottleLast.throttleLast(source, 400, TimeUnit.MILLISECONDS, scheduler));
+            sampled.subscribe(observer);
+
+            InOrder inOrder = inOrder(observer);
+
+            scheduler.advanceTimeTo(400, TimeUnit.MILLISECONDS);
+            inOrder.verify(observer).onNext("one");
+            scheduler.advanceTimeTo(701, TimeUnit.MILLISECONDS);
+            inOrder.verify(observer).onError(any(TestException.class));
+            inOrder.verifyNoMoreInteractions();
+        }
+
+        private <T> void publishCompleted(final Observer<T> observer, long delay) {
+            scheduler.schedule(new Action0() {
+                @Override
+                public void call() {
+                    observer.onCompleted();
+                }
+            }, delay, TimeUnit.MILLISECONDS);
+        }
+
+        private <T> void publishError(final Observer<T> observer, long delay, final Exception error) {
+            scheduler.schedule(new Action0() {
+                @Override
+                public void call() {
+                    observer.onError(error);
+                }
+            }, delay, TimeUnit.MILLISECONDS);
+        }
+
+        private <T> void publishNext(final Observer<T> observer, long delay, final T value) {
+            scheduler.schedule(new Action0() {
+                @Override
+                public void call() {
+                    observer.onNext(value);
+                }
+            }, delay, TimeUnit.MILLISECONDS);
+        }
+
+        @SuppressWarnings("serial")
+        private class TestException extends Exception {
+        }
+
+    }
+
+}

rxjava-core/src/test/java/rx/ThrottleLastTests.java

@@ -0,0 +1,46 @@
+package rx;
+
+import static org.mockito.Mockito.*;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Test;
+import org.mockito.InOrder;
+
+import rx.concurrency.TestScheduler;
+import rx.subjects.PublishSubject;
+
+public class ThrottleLastTests {
+
+    @Test
+    public void testThrottle() {
+        @SuppressWarnings("unchecked")
+        Observer<Integer> observer = mock(Observer.class);
+        TestScheduler s = new TestScheduler();
+        PublishSubject<Integer> o = PublishSubject.create();
+        o.throttleLast(500, TimeUnit.MILLISECONDS, s).subscribe(observer);
+
+        // send events with simulated time increments
+        s.advanceTimeTo(0, TimeUnit.MILLISECONDS);
+        o.onNext(1); // skip
+        o.onNext(2); // deliver
+        s.advanceTimeTo(501, TimeUnit.MILLISECONDS);
+        o.onNext(3); // skip
+        s.advanceTimeTo(600, TimeUnit.MILLISECONDS);
+        o.onNext(4); // skip
+        s.advanceTimeTo(700, TimeUnit.MILLISECONDS);
+        o.onNext(5); // skip
+        o.onNext(6); // deliver
+        s.advanceTimeTo(1001, TimeUnit.MILLISECONDS);
+        o.onNext(7); // deliver
+        s.advanceTimeTo(1501, TimeUnit.MILLISECONDS);
+        o.onCompleted();
+
+        InOrder inOrder = inOrder(observer);
+        inOrder.verify(observer).onNext(2);
+        inOrder.verify(observer).onNext(6);
+        inOrder.verify(observer).onNext(7);
+        inOrder.verify(observer).onCompleted();
+        inOrder.verifyNoMoreInteractions();
+    }
+}