Fixing Utils.addTimeOrdered loop and loop terminator to allow adding a window element to the front of a list

ripleyb · ripleyb · commit 53a6b24f856f · 2018-05-11T10:27:08.000-07:00
diff --git a/src/main/java/com/scaleoutsoftware/streaming/timewindowing/Utils.java b/src/main/java/com/scaleoutsoftware/streaming/timewindowing/Utils.java
@@ -33,16 +33,21 @@ static <T> void addTimeOrdered(List<T> source, TimestampSelector<T> selector, T
         int index = source.size() - 1;
         long timeToAdd = selector.select(toAdd);
         long last = selector.select(source.get(index));
+
         if(timeToAdd < last) {
-            while(timeToAdd < last) {
-                index--;
-                last = selector.select(source.get(index));
+            while(index > 0) {
+                if(timeToAdd < last) {
+                    index--;
+                    last = selector.select(source.get(index));
+                } else {
+                    index++;
+                    break;
+                }
             }
-            source.add(index++, toAdd);
+            source.add(index, toAdd);
         } else {
-            source.add(toAdd);
+            source.add(++index, toAdd);
         }
-
     }
 
     /**
diff --git a/src/test/java/com/scaleoutsoftware/streaming/timewindowing/tests/WindowingTests.java b/src/test/java/com/scaleoutsoftware/streaming/timewindowing/tests/WindowingTests.java
@@ -143,6 +143,24 @@ public void testUtilsAdd() {
         Assert.assertTrue(tumblingSource.size() == numElements);
     }
 
+    @Test
+    public void TestUtilsAddToFront() {
+        ArrayList<TestObject> list = new ArrayList<>(25);
+        long start = System.currentTimeMillis();
+        long every = 1000L;
+        long duration = 2500L;
+        SlidingWindowCollection<TestObject> swc = new SlidingWindowCollection<TestObject>(list,
+                test -> test.getTimestamp(),
+                duration,
+                every,
+                start);
+        long addToFront = System.currentTimeMillis();
+        swc.add(new TestObject(System.currentTimeMillis() + 1000L));
+        swc.add(new TestObject(addToFront));
+        Assert.assertTrue(list.size() == 2);
+        Assert.assertTrue(list.get(0).getTimestamp() == addToFront);
+    }
+
     @Test
     public void testEviction() {
         int numElements = 100;
