1 files changed, 17 insertions, 6 deletions

diff --git a/java/src/com/android/inputmethod/event/CombinerChain.java b/java/src/com/android/inputmethod/event/CombinerChain.java
index 8c6b3d949..2d2731f21 100644
--- a/java/src/com/android/inputmethod/event/CombinerChain.java
+++ b/java/src/com/android/inputmethod/event/CombinerChain.java
@@ -24,6 +24,8 @@ import com.android.inputmethod.latin.Constants;
 import java.util.ArrayList;
 import java.util.HashMap;
 
+import javax.annotation.Nonnull;
+
 /**
  * This class implements the logic chain between receiving events and generating code points.
  *
@@ -80,11 +82,21 @@ public class CombinerChain {
         }
     }
 
+    private void updateStateFeedback() {
+        mStateFeedback.clear();
+        for (int i = mCombiners.size() - 1; i >= 0; --i) {
+            mStateFeedback.append(mCombiners.get(i).getCombiningStateFeedback());
+        }
+    }
+
     /**
      * Process an event through the combining chain, and return a processed event to apply.
      * @param previousEvents the list of previous events in this composition
      * @param newEvent the new event to process
+     * @return the processed event. It may be the same event, or a consumed event, or a completely
+     *   new event. However it may never be null.
      */
+    @Nonnull
     public Event processEvent(final ArrayList<Event> previousEvents, final Event newEvent) {
         final ArrayList<Event> modifiablePreviousEvents = new ArrayList<>(previousEvents);
         Event event = newEvent;
@@ -92,11 +104,13 @@ public class CombinerChain {
             // A combiner can never return more than one event; it can return several
             // code points, but they should be encapsulated within one event.
             event = combiner.processEvent(modifiablePreviousEvents, event);
-            if (null == event) {
-                // Combiners return null if they eat the event.
+            if (event.isConsumed()) {
+                // If the event is consumed, then we don't pass it to subsequent combiners:
+                // they should not see it at all.
                 break;
             }
         }
+        updateStateFeedback();
         return event;
     }
 
@@ -120,10 +134,7 @@ public class CombinerChain {
                 }
             }
         }
-        mStateFeedback.clear();
-        for (int i = mCombiners.size() - 1; i >= 0; --i) {
-            mStateFeedback.append(mCombiners.get(i).getCombiningStateFeedback());
-        }
+        updateStateFeedback();
     }
 
     /**