Merge "Add BatchInputArbiter"

java/src/com/android/inputmethod/keyboard/PointerTracker.java

@@ -22,12 +22,13 @@ import android.os.SystemClock;
 import android.util.Log;
 import android.view.MotionEvent;
 
+import com.android.inputmethod.keyboard.internal.BatchInputArbiter;
+import com.android.inputmethod.keyboard.internal.BatchInputArbiter.BatchInputArbiterListener;
 import com.android.inputmethod.keyboard.internal.BogusMoveEventDetector;
 import com.android.inputmethod.keyboard.internal.GestureEnabler;
 import com.android.inputmethod.keyboard.internal.GestureStrokeDrawingParams;
 import com.android.inputmethod.keyboard.internal.GestureStrokeDrawingPoints;
 import com.android.inputmethod.keyboard.internal.GestureStrokeRecognitionParams;
-import com.android.inputmethod.keyboard.internal.GestureStrokeRecognitionPoints;
 import com.android.inputmethod.keyboard.internal.PointerTrackerQueue;
 import com.android.inputmethod.keyboard.internal.TypingTimeRecorder;
 import com.android.inputmethod.latin.Constants;
@@ -43,7 +44,8 @@ import com.android.inputmethod.research.ResearchLogger;
 
 import java.util.ArrayList;
 
-public final class PointerTracker implements PointerTrackerQueue.Element {
+public final class PointerTracker implements PointerTrackerQueue.Element,
+        BatchInputArbiterListener {
     private static final String TAG = PointerTracker.class.getSimpleName();
     private static final boolean DEBUG_EVENT = false;
     private static final boolean DEBUG_MOVE_EVENT = false;
@@ -160,12 +162,7 @@ public final class PointerTracker implements PointerTrackerQueue.Element {
 
     private boolean mIsDetectingGesture = false; // per PointerTracker.
     private static boolean sInGesture = false;
-    private static long sGestureFirstDownTime;
     private static TypingTimeRecorder sTypingTimeRecorder;
-    private static final InputPointers sAggregatedPointers = new InputPointers(
-            GestureStrokeRecognitionPoints.DEFAULT_CAPACITY);
-    private static int sLastRecognitionPointSize = 0; // synchronized using sAggregatedPointers
-    private static long sLastRecognitionTime = 0; // synchronized using sAggregatedPointers
 
     // The position and time at which first down event occurred.
     private long mDownTime;
@@ -203,7 +200,7 @@ public final class PointerTracker implements PointerTrackerQueue.Element {
     // true if dragging finger is allowed.
     private boolean mIsAllowedDraggingFinger;
 
-    private final GestureStrokeRecognitionPoints mGestureStrokeRecognitionPoints;
+    private final BatchInputArbiter mBatchInputArbiter;
     private final GestureStrokeDrawingPoints mGestureStrokeDrawingPoints;
 
     // TODO: Add PointerTrackerFactory singleton and move some class static methods into it.
@@ -287,8 +284,7 @@ public final class PointerTracker implements PointerTrackerQueue.Element {
 
     private PointerTracker(final int id) {
         mPointerId = id;
-        mGestureStrokeRecognitionPoints = new GestureStrokeRecognitionPoints(
+        mBatchInputArbiter = new BatchInputArbiter(id, sGestureStrokeRecognitionParams);
-                id, sGestureStrokeRecognitionParams);
         mGestureStrokeDrawingPoints = new GestureStrokeDrawingPoints(sGestureStrokeDrawingParams);
     }
 
@@ -410,7 +406,7 @@ public final class PointerTracker implements PointerTrackerQueue.Element {
         mKeyboardLayoutHasBeenChanged = true;
         final int keyWidth = mKeyboard.mMostCommonKeyWidth;
         final int keyHeight = mKeyboard.mMostCommonKeyHeight;
-        mGestureStrokeRecognitionPoints.setKeyboardGeometry(keyWidth, mKeyboard.mOccupiedHeight);
+        mBatchInputArbiter.setKeyboardGeometry(keyWidth, mKeyboard.mOccupiedHeight);
         final Key newKey = mKeyDetector.detectHitKey(mKeyX, mKeyY);
         if (newKey != mCurrentKey) {
             if (sDrawingProxy != null) {
@@ -578,27 +574,16 @@ public final class PointerTracker implements PointerTrackerQueue.Element {
         return sPointerTrackerQueue.getOldestElement() == this;
     }
 
-    /**
+    // Implements {@link BatchInputArbiterListener}.
-     * Determines whether the batch input has started or not.
+    @Override
-     * @return true if the batch input has started successfully.
+    public void onStartBatchInput() {
-     */
-    private boolean mayStartBatchInput() {
-        if (!mGestureStrokeRecognitionPoints.isStartOfAGesture()) {
-            return false;
-        }
         if (DEBUG_LISTENER) {
             Log.d(TAG, String.format("[%d] onStartBatchInput", mPointerId));
         }
-        synchronized (sAggregatedPointers) {
-            sAggregatedPointers.reset();
-            sLastRecognitionPointSize = 0;
-            sLastRecognitionTime = 0;
         sListener.onStartBatchInput();
         dismissAllMoreKeysPanels();
         sTimerProxy.cancelLongPressTimerOf(this);
     }
-        return true;
-    }
 
     private void showGestureTrail() {
         if (mIsTrackingForActionDisabled) {
@@ -610,55 +595,38 @@ public final class PointerTracker implements PointerTrackerQueue.Element {
     }
 
     public void updateBatchInputByTimer(final long syntheticMoveEventTime) {
-        final int gestureTime = (int)(syntheticMoveEventTime - sGestureFirstDownTime);
+        mBatchInputArbiter.updateBatchInputByTimer(syntheticMoveEventTime, this);
-        mGestureStrokeRecognitionPoints.duplicateLastPointWith(gestureTime);
-        updateBatchInput(syntheticMoveEventTime);
     }
 
-    private void updateBatchInput(final long moveEventTime) {
+    // Implements {@link BatchInputArbiterListener}.
-        synchronized (sAggregatedPointers) {
+    @Override
-            final GestureStrokeRecognitionPoints stroke = mGestureStrokeRecognitionPoints;
+    public void onUpdateBatchInput(final InputPointers aggregatedPointers, final long eventTime) {
-            stroke.appendIncrementalBatchPoints(sAggregatedPointers);
-            final int size = sAggregatedPointers.getPointerSize();
-            if (size > sLastRecognitionPointSize
-                    && stroke.hasRecognitionTimePast(moveEventTime, sLastRecognitionTime)) {
         if (DEBUG_LISTENER) {
             Log.d(TAG, String.format("[%d] onUpdateBatchInput: batchPoints=%d", mPointerId,
-                            size));
+                    aggregatedPointers.getPointerSize()));
-                }
-                sTimerProxy.startUpdateBatchInputTimer(this);
-                sListener.onUpdateBatchInput(sAggregatedPointers);
-                // The listener may change the size of the pointers (when auto-committing
-                // for example), so we need to get the size from the pointers again.
-                sLastRecognitionPointSize = sAggregatedPointers.getPointerSize();
-                sLastRecognitionTime = moveEventTime;
-            }
         }
+        sListener.onUpdateBatchInput(aggregatedPointers);
     }
 
-    /**
+    // Implements {@link BatchInputArbiterListener}.
-     * Determines whether the batch input has ended successfully or continues.
+    @Override
-     * @param upEventTime the event time of this pointer up.
+    public void onStartUpdateBatchInputTimer() {
-     * @return true if the batch input has ended successfully, false if it continues.
+        sTimerProxy.startUpdateBatchInputTimer(this);
-     */
+    }
-    private boolean mayEndBatchInput(final long upEventTime) {
+
-        boolean hasEndBatchInputSuccessfully = false;
+    // Implements {@link BatchInputArbiterListener}.
-        synchronized (sAggregatedPointers) {
+    @Override
-            mGestureStrokeRecognitionPoints.appendAllBatchPoints(sAggregatedPointers);
+    public void onEndBatchInput(final InputPointers aggregatedPointers, final long eventTime) {
-            if (getActivePointerTrackerCount() == 1) {
+        sTypingTimeRecorder.onEndBatchInput(eventTime);
-                hasEndBatchInputSuccessfully = true;
-                sTypingTimeRecorder.onEndBatchInput(upEventTime);
         sTimerProxy.cancelAllUpdateBatchInputTimers();
-                if (!mIsTrackingForActionDisabled) {
+        if (mIsTrackingForActionDisabled) {
+            return;
+        }
         if (DEBUG_LISTENER) {
             Log.d(TAG, String.format("[%d] onEndBatchInput   : batchPoints=%d",
-                                mPointerId, sAggregatedPointers.getPointerSize()));
+                    mPointerId, aggregatedPointers.getPointerSize()));
         }
-                    sListener.onEndBatchInput(sAggregatedPointers);
+        sListener.onEndBatchInput(aggregatedPointers);
-                }
-            }
-        }
-        return hasEndBatchInputSuccessfully;
     }
 
     private void cancelBatchInput() {
@@ -753,15 +721,10 @@ public final class PointerTracker implements PointerTrackerQueue.Element {
         mIsDetectingGesture = (mKeyboard != null) && mKeyboard.mId.isAlphabetKeyboard()
                 && key != null && !key.isModifier();
         if (mIsDetectingGesture) {
-            if (getActivePointerTrackerCount() == 1) {
+            mBatchInputArbiter.addDownEventPoint(x, y, eventTime,
-                sGestureFirstDownTime = eventTime;
+                    sTypingTimeRecorder.getLastLetterTypingTime(), getActivePointerTrackerCount());
-            }
+            mGestureStrokeDrawingPoints.onDownEvent(
-            final int elapsedTimeSinceFirstDown = (int)(eventTime - sGestureFirstDownTime);
+                    x, y, mBatchInputArbiter.getElapsedTimeSinceFirstDown(eventTime));
-            final int elapsedTimeSinceLastTyping = (int)(
-                    eventTime - sTypingTimeRecorder.getLastLetterTypingTime());
-            mGestureStrokeRecognitionPoints.onDownEvent(x, y, elapsedTimeSinceFirstDown,
-                    elapsedTimeSinceLastTyping);
-            mGestureStrokeDrawingPoints.onDownEvent(x, y, elapsedTimeSinceFirstDown);
         }
     }
 
@@ -820,31 +783,27 @@ public final class PointerTracker implements PointerTrackerQueue.Element {
         if (!mIsDetectingGesture) {
             return;
         }
-        final int beforeLength = mGestureStrokeRecognitionPoints.getLength();
+        final boolean onValidArea = mBatchInputArbiter.addMoveEventPoint(
-        final int elapsedTimeSinceFirstDown = (int)(eventTime - sGestureFirstDownTime);
+                x, y, eventTime, isMajorEvent, this);
-        final boolean onValidArea = mGestureStrokeRecognitionPoints.addPointOnKeyboard(
-                x, y, elapsedTimeSinceFirstDown, isMajorEvent);
-        if (mGestureStrokeRecognitionPoints.getLength() > beforeLength) {
-            sTimerProxy.startUpdateBatchInputTimer(this);
-        }
         // If the move event goes out from valid batch input area, cancel batch input.
         if (!onValidArea) {
             cancelBatchInput();
             return;
         }
-        mGestureStrokeDrawingPoints.onMoveEvent(x, y, elapsedTimeSinceFirstDown);
+        mGestureStrokeDrawingPoints.onMoveEvent(
+                x, y, mBatchInputArbiter.getElapsedTimeSinceFirstDown(eventTime));
         // If the MoreKeysPanel is showing then do not attempt to enter gesture mode. However,
         // the gestured touch points are still being recorded in case the panel is dismissed.
         if (isShowingMoreKeysPanel()) {
             return;
         }
         if (!sInGesture && key != null && Character.isLetter(key.getCode())
-                && mayStartBatchInput()) {
+                && mBatchInputArbiter.mayStartBatchInput(this)) {
             sInGesture = true;
         }
         if (sInGesture) {
             if (key != null) {
-                updateBatchInput(eventTime);
+                mBatchInputArbiter.updateBatchInput(eventTime, this);
             }
             showGestureTrail();
         }
@@ -1097,7 +1056,8 @@ public final class PointerTracker implements PointerTrackerQueue.Element {
             if (currentKey != null) {
                 callListenerOnRelease(currentKey, currentKey.getCode(), true /* withSliding */);
             }
-            if (mayEndBatchInput(eventTime)) {
+            if (mBatchInputArbiter.mayEndBatchInput(
+                    eventTime, getActivePointerTrackerCount(), this)) {
                 sInGesture = false;
             }
             showGestureTrail();

java/src/com/android/inputmethod/keyboard/internal/BatchInputArbiter.java

@@ -0,0 +1,181 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * 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 com.android.inputmethod.keyboard.internal;
+
+import com.android.inputmethod.latin.Constants;
+import com.android.inputmethod.latin.InputPointers;
+
+/**
+ * This class arbitrates batch input.
+ * An instance of this class holds a {@link GestureStrokeRecognitionPoints}.
+ * And it arbitrates multiple strokes gestured by multiple fingers and aggregates those gesture
+ * points into one batch input.
+ */
+public class BatchInputArbiter {
+    public interface BatchInputArbiterListener {
+        public void onStartBatchInput();
+        public void onUpdateBatchInput(
+                final InputPointers aggregatedPointers, final long moveEventTime);
+        public void onStartUpdateBatchInputTimer();
+        public void onEndBatchInput(final InputPointers aggregatedPointers, final long upEventTime);
+    }
+
+    // The starting time of the first stroke of a gesture input.
+    private static long sGestureFirstDownTime;
+    // The {@link InputPointers} that includes all events of a gesture input.
+    private static final InputPointers sAggregatedPointers = new InputPointers(
+            Constants.DEFAULT_GESTURE_POINTS_CAPACITY);
+    private static int sLastRecognitionPointSize = 0; // synchronized using sAggregatedPointers
+    private static long sLastRecognitionTime = 0; // synchronized using sAggregatedPointers
+
+    private final GestureStrokeRecognitionPoints mRecognitionPoints;
+
+    public BatchInputArbiter(final int pointerId, final GestureStrokeRecognitionParams params) {
+        mRecognitionPoints = new GestureStrokeRecognitionPoints(pointerId, params);
+    }
+
+    public void setKeyboardGeometry(final int keyWidth, final int keyboardHeight) {
+        mRecognitionPoints.setKeyboardGeometry(keyWidth, keyboardHeight);
+    }
+
+    /**
+     * Calculate elapsed time since the first gesture down.
+     * @param eventTime the time of this event.
+     * @return the elapsed time in millisecond from the first gesture down.
+     */
+    public int getElapsedTimeSinceFirstDown(final long eventTime) {
+        return (int)(eventTime - sGestureFirstDownTime);
+    }
+
+    /**
+     * Add a down event point.
+     * @param x the x-coordinate of this down event.
+     * @param y the y-coordinate of this down event.
+     * @param downEventTime the time of this down event.
+     * @param lastLetterTypingTime the last typing input time.
+     * @param activePointerCount the number of active pointers when this pointer down event occurs.
+     */
+    public void addDownEventPoint(final int x, final int y, final long downEventTime,
+            final long lastLetterTypingTime, final int activePointerCount) {
+        if (activePointerCount == 1) {
+            sGestureFirstDownTime = downEventTime;
+        }
+        final int elapsedTimeSinceFirstDown = getElapsedTimeSinceFirstDown(downEventTime);
+        final int elapsedTimeSinceLastTyping = (int)(downEventTime - lastLetterTypingTime);
+        mRecognitionPoints.addDownEventPoint(
+                x, y, elapsedTimeSinceFirstDown, elapsedTimeSinceLastTyping);
+    }
+
+    /**
+     * Add a move event point.
+     * @param x the x-coordinate of this move event.
+     * @param y the y-coordinate of this move event.
+     * @param moveEventTime the time of this move event.
+     * @param isMajorEvent false if this is a historical move event.
+     * @param listener {@link BatchInputArbiterListener#onStartUpdateBatchInputTimer()} of this
+     *     <code>listener</code> may be called if enough move points have been added.
+     * @return true if this move event occurs on the valid gesture area.
+     */
+    public boolean addMoveEventPoint(final int x, final int y, final long moveEventTime,
+            final boolean isMajorEvent, final BatchInputArbiterListener listener) {
+        final int beforeLength = mRecognitionPoints.getLength();
+        final boolean onValidArea = mRecognitionPoints.addEventPoint(
+                x, y, getElapsedTimeSinceFirstDown(moveEventTime), isMajorEvent);
+        if (mRecognitionPoints.getLength() > beforeLength) {
+            listener.onStartUpdateBatchInputTimer();
+        }
+        return onValidArea;
+    }
+
+    /**
+     * Determine whether the batch input has started or not.
+     * @param listener {@link BatchInputArbiterListener#onStartBatchInput()} of this
+     *     <code>listener</code> will be called when the batch input has started successfully.
+     * @return true if the batch input has started successfully.
+     */
+    public boolean mayStartBatchInput(final BatchInputArbiterListener listener) {
+        if (!mRecognitionPoints.isStartOfAGesture()) {
+            return false;
+        }
+        synchronized (sAggregatedPointers) {
+            sAggregatedPointers.reset();
+            sLastRecognitionPointSize = 0;
+            sLastRecognitionTime = 0;
+            listener.onStartBatchInput();
+        }
+        return true;
+    }
+
+    /**
+     * Add synthetic move event point. After adding the point,
+     * {@link #updateBatchInput(long,BatchInputArbiterListener)} will be called internally.
+     * @param syntheticMoveEventTime the synthetic move event time.
+     * @param listener the listener to be passed to
+     *     {@link #updateBatchInput(long,BatchInputArbiterListener)}.
+     */
+    public void updateBatchInputByTimer(final long syntheticMoveEventTime,
+            final BatchInputArbiterListener listener) {
+        mRecognitionPoints.duplicateLastPointWith(
+                getElapsedTimeSinceFirstDown(syntheticMoveEventTime));
+        updateBatchInput(syntheticMoveEventTime, listener);
+    }
+
+    /**
+     * Determine whether we have enough gesture points to lookup dictionary.
+     * @param moveEventTime the time of this move event.
+     * @param listener {@link BatchInputArbiterListener#onUpdateBatchInput(InputPointers,long)} of
+     *     this <code>listener</code> will be called when enough event points we have. Also
+     *     {@link BatchInputArbiterListener#onStartUpdateBatchInputTimer()} will be called to have
+     *     possible future synthetic move event.
+     */
+    public void updateBatchInput(final long moveEventTime,
+            final BatchInputArbiterListener listener) {
+        synchronized (sAggregatedPointers) {
+            mRecognitionPoints.appendIncrementalBatchPoints(sAggregatedPointers);
+            final int size = sAggregatedPointers.getPointerSize();
+            if (size > sLastRecognitionPointSize && mRecognitionPoints.hasRecognitionTimePast(
+                    moveEventTime, sLastRecognitionTime)) {
+                listener.onUpdateBatchInput(sAggregatedPointers, moveEventTime);
+                listener.onStartUpdateBatchInputTimer();
+                // The listener may change the size of the pointers (when auto-committing
+                // for example), so we need to get the size from the pointers again.
+                sLastRecognitionPointSize = sAggregatedPointers.getPointerSize();
+                sLastRecognitionTime = moveEventTime;
+            }
+        }
+    }
+
+    /**
+     * Determine whether the batch input has ended successfully or continues.
+     * @param upEventTime the time of this up event.
+     * @param activePointerCount the number of active pointers when this pointer up event occurs.
+     * @param listener {@link BatchInputArbiterListener#onEndBatchInput(InputPointers,long)} of this
+     *     <code>listener</code> will be called when the batch input has started successfully.
+     * @return true if the batch input has ended successfully.
+     */
+    public boolean mayEndBatchInput(final long upEventTime, final int activePointerCount,
+            final BatchInputArbiterListener listener) {
+        synchronized (sAggregatedPointers) {
+            mRecognitionPoints.appendAllBatchPoints(sAggregatedPointers);
+            if (activePointerCount == 1) {
+                listener.onEndBatchInput(sAggregatedPointers, upEventTime);
+                return true;
+            }
+        }
+        return false;
+    }
+}

java/src/com/android/inputmethod/keyboard/internal/GestureStrokeRecognitionPoints.java

@@ -18,14 +18,15 @@ package com.android.inputmethod.keyboard.internal;
 
 import android.util.Log;
 
+import com.android.inputmethod.latin.Constants;
 import com.android.inputmethod.latin.InputPointers;
 import com.android.inputmethod.latin.utils.ResizableIntArray;
 
 /**
  * This class holds event points to recognize a gesture stroke.
- * TODO: Should be final and package private class.
+ * TODO: Should be package private class.
  */
-public class GestureStrokeRecognitionPoints {
+public final class GestureStrokeRecognitionPoints {
     private static final String TAG = GestureStrokeRecognitionPoints.class.getSimpleName();
     private static final boolean DEBUG = false;
     private static final boolean DEBUG_SPEED = false;
@@ -34,12 +35,13 @@ public class GestureStrokeRecognitionPoints {
     // Proportional to the keyboard height.
     public static final float EXTRA_GESTURE_TRAIL_AREA_ABOVE_KEYBOARD_RATIO = 0.25f;
 
-    public static final int DEFAULT_CAPACITY = 128;
-
     private final int mPointerId;
-    private final ResizableIntArray mEventTimes = new ResizableIntArray(DEFAULT_CAPACITY);
+    private final ResizableIntArray mEventTimes = new ResizableIntArray(
-    private final ResizableIntArray mXCoordinates = new ResizableIntArray(DEFAULT_CAPACITY);
+            Constants.DEFAULT_GESTURE_POINTS_CAPACITY);
-    private final ResizableIntArray mYCoordinates = new ResizableIntArray(DEFAULT_CAPACITY);
+    private final ResizableIntArray mXCoordinates = new ResizableIntArray(
+            Constants.DEFAULT_GESTURE_POINTS_CAPACITY);
+    private final ResizableIntArray mYCoordinates = new ResizableIntArray(
+            Constants.DEFAULT_GESTURE_POINTS_CAPACITY);
 
     private final GestureStrokeRecognitionParams mRecognitionParams;
 
@@ -67,12 +69,14 @@ public class GestureStrokeRecognitionPoints {
 
     private static final int MSEC_PER_SEC = 1000;
 
+    // TODO: Make this package private
     public GestureStrokeRecognitionPoints(final int pointerId,
             final GestureStrokeRecognitionParams recognitionParams) {
         mPointerId = pointerId;
         mRecognitionParams = recognitionParams;
     }
 
+    // TODO: Make this package private
     public void setKeyboardGeometry(final int keyWidth, final int keyboardHeight) {
         mKeyWidth = keyWidth;
         mMinYCoordinate = -(int)(keyboardHeight * EXTRA_GESTURE_TRAIL_AREA_ABOVE_KEYBOARD_RATIO);
@@ -99,11 +103,13 @@ public class GestureStrokeRecognitionPoints {
         }
     }
 
+    // TODO: Make this package private
     public int getLength() {
         return mEventTimes.getLength();
     }
 
-    public void onDownEvent(final int x, final int y, final int elapsedTimeSinceFirstDown,
+    // TODO: Make this package private
+    public void addDownEventPoint(final int x, final int y, final int elapsedTimeSinceFirstDown,
             final int elapsedTimeSinceLastTyping) {
         reset();
         if (elapsedTimeSinceLastTyping < mRecognitionParams.mStaticTimeThresholdAfterFastTyping) {
@@ -113,7 +119,9 @@ public class GestureStrokeRecognitionPoints {
             Log.d(TAG, String.format("[%d] onDownEvent: dT=%3d%s", mPointerId,
                     elapsedTimeSinceLastTyping, mAfterFastTyping ? " afterFastTyping" : ""));
         }
-        addPointOnKeyboard(x, y, elapsedTimeSinceFirstDown, true /* isMajorEvent */);
+        // Call {@link #addEventPoint(int,int,int,boolean)} to record this down event point as a
+        // major event point.
+        addEventPoint(x, y, elapsedTimeSinceFirstDown, true /* isMajorEvent */);
     }
 
     private int getGestureDynamicDistanceThreshold(final int deltaTime) {
@@ -137,6 +145,7 @@ public class GestureStrokeRecognitionPoints {
         return mRecognitionParams.mDynamicTimeThresholdFrom - decayedThreshold;
     }
 
+    // TODO: Make this package private
     public final boolean isStartOfAGesture() {
         if (!hasDetectedFastMove()) {
             return false;
@@ -167,6 +176,7 @@ public class GestureStrokeRecognitionPoints {
         return isStartOfAGesture;
     }
 
+    // TODO: Make this package private
     public void duplicateLastPointWith(final int time) {
         final int lastIndex = getLength() - 1;
         if (lastIndex >= 0) {
@@ -250,19 +260,20 @@ public class GestureStrokeRecognitionPoints {
     }
 
     /**
-     * Add a touch event as a gesture point. Returns true if the touch event is on the valid
+     * Add an event point to this gesture stroke recognition points. Returns true if the event
-     * gesture area.
+     * point is on the valid gesture area.
-     * @param x the x-coordinate of the touch event
+     * @param x the x-coordinate of the event point
-     * @param y the y-coordinate of the touch event
+     * @param y the y-coordinate of the event point
      * @param time the elapsed time in millisecond from the first gesture down
      * @param isMajorEvent false if this is a historical move event
-     * @return true if the touch event is on the valid gesture area
+     * @return true if the event point is on the valid gesture area
      */
-    public boolean addPointOnKeyboard(final int x, final int y, final int time,
+    // TODO: Make this package private
+    public boolean addEventPoint(final int x, final int y, final int time,
             final boolean isMajorEvent) {
         final int size = getLength();
         if (size <= 0) {
-            // Down event
+            // The first event of this stroke (a.k.a. down event).
             appendPoint(x, y, time);
             updateMajorEvent(x, y, time);
         } else {
@@ -291,15 +302,18 @@ public class GestureStrokeRecognitionPoints {
         }
     }
 
+    // TODO: Make this package private
     public final boolean hasRecognitionTimePast(
             final long currentTime, final long lastRecognitionTime) {
         return currentTime > lastRecognitionTime + mRecognitionParams.mRecognitionMinimumTime;
     }
 
+    // TODO: Make this package private
     public final void appendAllBatchPoints(final InputPointers out) {
         appendBatchPoints(out, getLength());
     }
 
+    // TODO: Make this package private
     public final void appendIncrementalBatchPoints(final InputPointers out) {
         appendBatchPoints(out, mIncrementalRecognitionSize);
     }

java/src/com/android/inputmethod/latin/Constants.java

@@ -257,6 +257,13 @@ public final class Constants {
     public static final int SCREEN_METRICS_LARGE_TABLET = 2;
     public static final int SCREEN_METRICS_SMALL_TABLET = 3;
 
+    /**
+     * Default capacity of gesture points container.
+     * This constant is used by {@link BatchInputArbiter} and etc. to preallocate regions that
+     * contain gesture event points.
+     */
+    public static final int DEFAULT_GESTURE_POINTS_CAPACITY = 128;
+
     private Constants() {
         // This utility class is not publicly instantiable.
     }