add timer methods in Observable.java

Author: samuelgruetter

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

@@ -91,6 +91,7 @@
 import rx.operators.OperationThrottleFirst;
 import rx.operators.OperationTimeInterval;
 import rx.operators.OperationTimeout;
+import rx.operators.OperationTimer;
 import rx.operators.OperationTimestamp;
 import rx.operators.OperationToMap;
 import rx.operators.OperationToMultimap;
@@ -1990,6 +1991,33 @@ public static Observable<Long> interval(long interval, TimeUnit unit, Scheduler
         return create(OperationInterval.interval(interval, unit, scheduler));
     }
 
+    /**
+     * Emits one item after a given delay, and then completes.
+     * 
+     * @param interval
+     *            interval size in time units
+     * @param unit
+     *            time units to use for the interval size
+     */
+    public static Observable<Void> timer(long interval, TimeUnit unit) {
+        return create(OperationTimer.timer(interval, unit));
+    }
+
+    /**
+     * Emits one item after a given delay, and then completes.
+     * 
+     * @param interval
+     *            interval size in time units
+     * @param unit
+     *            time units to use for the interval size
+     * @param scheduler
+     *            the scheduler to use for scheduling the item
+     */
+    public static Observable<Void> timer(long interval, TimeUnit unit,
+            Scheduler scheduler) {
+        return create(OperationTimer.timer(interval, unit, scheduler));
+    }
+
     /**
      * Drops items emitted by an Observable that are followed by newer items
      * before a timeout value expires. The timer resets on each emission.