Merge pull request #249 from jmhofer/timestamp

Timestamp operation

Author: benjchristensen

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

@@ -65,6 +65,7 @@
 import rx.operators.OperationTakeLast;
 import rx.operators.OperationTakeUntil;
 import rx.operators.OperationTakeWhile;
+import rx.operators.OperationTimestamp;
 import rx.operators.OperationToFuture;
 import rx.operators.OperationToIterator;
 import rx.operators.OperationToObservableFuture;
@@ -82,6 +83,7 @@
 import rx.util.AtomicObservableSubscription;
 import rx.util.AtomicObserver;
 import rx.util.Range;
+import rx.util.Timestamped;
 import rx.util.functions.Action0;
 import rx.util.functions.Action1;
 import rx.util.functions.Func0;
@@ -2093,6 +2095,14 @@ public Boolean call(T t, Integer integer)
         }));
     }
 
+    /**
+     * Adds a timestamp to each item emitted by this observable.
+     * @return An observable sequence of timestamped items.
+     */
+    public Observable<Timestamped<T>> timestamp() {
+        return create(OperationTimestamp.timestamp(this));
+    }
+    
     /**
      * Return a Future representing a single value of the Observable.
      * <p>

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

@@ -0,0 +1,43 @@
+/**
+ * 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 rx.Observable;
+import rx.Observer;
+import rx.Subscription;
+import rx.util.Timestamped;
+import rx.util.functions.Func1;
+
+public final class OperationTimestamp {
+
+    /**
+     * Accepts a sequence and adds timestamps to each item in it.
+     * 
+     * @param sequence
+     *            the input sequence.
+     * @param <T>
+     *            the type of the input sequence.
+     * @return a sequence of timestamped values created by adding timestamps to each item in the input sequence.
+     */
+    public static <T> Func1<Observer<Timestamped<T>>, Subscription> timestamp(Observable<T> sequence) {
+        return OperationMap.map(sequence, new Func1<T, Timestamped<T>>() {
+            @Override
+            public Timestamped<T> call(T value) {
+                return new Timestamped<T>(System.currentTimeMillis(), value);
+            }
+        });
+    }
+}

rxjava-core/src/main/java/rx/util/Timestamped.java

@@ -0,0 +1,73 @@
+/**
+ * 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.util;
+
+/**
+ * Composite class that takes a value and a timestamp and wraps them.   
+ */
+public final class Timestamped<T> {
+    private final long timestampMillis;
+    private final T value;
+
+    public Timestamped(long timestampMillis, T value) {
+        this.value = value;
+        this.timestampMillis = timestampMillis;
+    }
+
+    public long getTimestampMillis() {
+        return timestampMillis;
+    }
+
+    public T getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (!(obj instanceof Timestamped)) {
+            return false;
+        }
+        Timestamped<?> other = (Timestamped<?>) obj;
+        if (timestampMillis != other.timestampMillis) {
+            return false;
+        }
+        if (value == null) {
+            if (other.value != null) {
+                return false;
+            }
+        } else if (!value.equals(other.value)) {
+            return false;
+        }
+        return true;
+    }
+    
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + (int) (timestampMillis ^ (timestampMillis));
+        result = prime * result + ((value == null) ? 0 : value.hashCode());
+        return result;
+    }
+    
+    @Override
+    public String toString() {
+        return String.format("Timestamped(timestampMillis = %d, value = %s)", timestampMillis, value.toString());
+    }
+}