Operation Timestamp with Scheduler

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

@@ -2207,6 +2207,19 @@ public Observable<Timestamped<T>> timestamp() {
         return create(OperationTimestamp.timestamp(this));
     }
 
+    /**
+     * Wraps each item emitted by a source Observable in a {@link Timestamped}
+     * object with timestamps provided by the given Scheduler.
+     * 
+     * @param scheduler the {@link Scheduler} to use as a time source.
+     * @return an Observable that emits timestamped items from the source
+     *         Observable with timestamps provided by the given Scheduler
+     * @see <a href='http://msdn.microsoft.com/en-us/library/hh229003.aspx'>MSDN: Observable.Timestamp</a>
+     */
+    public Observable<Timestamped<T>> timestamp(Scheduler scheduler) {
+        return create(OperationTimestamp.timestamp(this, scheduler));
+    }
+
     /**
      * Converts a {@link Future} into an Observable.
      * <p>

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

@@ -17,6 +17,7 @@
 
 import rx.Observable;
 import rx.Observable.OnSubscribeFunc;
+import rx.Scheduler;
 import rx.util.Timestamped;
 import rx.util.functions.Func1;
 
@@ -44,4 +45,15 @@ public Timestamped<T> call(T value) {
             }
         });
     }
+    /**
+     * Timestamp the source elements based on the timing provided by the scheduler.
+     */
+    public static <T> OnSubscribeFunc<Timestamped<T>> timestamp(Observable<? extends T> source, final Scheduler scheduler) {
+        return OperationMap.map(source, new Func1<T, Timestamped<T>>() {
+            @Override
+            public Timestamped<T> call(T value) {
+                return new Timestamped<T>(scheduler.now(), value);
+            }
+        });
+    }
 }

rxjava-core/src/test/java/rx/operators/OperationTimestampTest.java

@@ -0,0 +1,86 @@
+/**
+ * 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 java.util.concurrent.TimeUnit;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import static org.mockito.Mockito.*;
+import org.mockito.MockitoAnnotations;
+import rx.Observable;
+import rx.Observer;
+import rx.concurrency.TestScheduler;
+import rx.subjects.PublishSubject;
+import rx.util.Timestamped;
+
+public class OperationTimestampTest {
+    @Mock
+    Observer<Object> observer;
+    @Before
+    public void before() {
+        MockitoAnnotations.initMocks(this);
+    }
+    @Test
+    public void timestampWithScheduler() {
+        TestScheduler scheduler = new TestScheduler();
+
+        PublishSubject<Integer> source = PublishSubject.create();
+        Observable<Timestamped<Integer>> m = source.timestamp(scheduler);
+        m.subscribe(observer);
+
+        source.onNext(1);
+        scheduler.advanceTimeBy(100, TimeUnit.MILLISECONDS);
+        source.onNext(2);
+        scheduler.advanceTimeBy(100, TimeUnit.MILLISECONDS);
+        source.onNext(3);
+
+
+        InOrder inOrder = inOrder(observer);
+
+        inOrder.verify(observer, times(1)).onNext(new Timestamped<Integer>(0, 1));
+        inOrder.verify(observer, times(1)).onNext(new Timestamped<Integer>(100, 2));
+        inOrder.verify(observer, times(1)).onNext(new Timestamped<Integer>(200, 3));
+
+        verify(observer, never()).onError(any(Throwable.class));
+        verify(observer, never()).onCompleted();
+    }
+    @Test
+    public void timestampWithScheduler2() {
+        TestScheduler scheduler = new TestScheduler();
+
+        PublishSubject<Integer> source = PublishSubject.create();
+        Observable<Timestamped<Integer>> m = source.timestamp(scheduler);
+        m.subscribe(observer);
+
+        source.onNext(1);
+        source.onNext(2);
+        scheduler.advanceTimeBy(100, TimeUnit.MILLISECONDS);
+        scheduler.advanceTimeBy(100, TimeUnit.MILLISECONDS);
+        source.onNext(3);
+
+
+        InOrder inOrder = inOrder(observer);
+
+        inOrder.verify(observer, times(1)).onNext(new Timestamped<Integer>(0, 1));
+        inOrder.verify(observer, times(1)).onNext(new Timestamped<Integer>(0, 2));
+        inOrder.verify(observer, times(1)).onNext(new Timestamped<Integer>(200, 3));
+
+        verify(observer, never()).onError(any(Throwable.class));
+        verify(observer, never()).onCompleted();
+    }
+}