1 files changed, 12 insertions, 16 deletions
diff --git a/java/src/com/android/inputmethod/latin/NgramContext.java b/java/src/com/android/inputmethod/latin/NgramContext.java
index a02531cc4..82a13274d 100644
--- a/java/src/com/android/inputmethod/latin/NgramContext.java
+++ b/java/src/com/android/inputmethod/latin/NgramContext.java
@@ -19,26 +19,33 @@ package com.android.inputmethod.latin;
 import android.text.TextUtils;
 
 import com.android.inputmethod.annotations.UsedForTesting;
-import com.android.inputmethod.latin.utils.StringUtils;
+import com.android.inputmethod.latin.common.Constants;
+import com.android.inputmethod.latin.common.StringUtils;
 
 import java.util.Arrays;
 
+import javax.annotation.Nonnull;
+
 /**
  * Class to represent information of previous words. This class is used to add n-gram entries
  * into binary dictionaries, to get predictions, and to get suggestions.
  */
 public class NgramContext {
+    @Nonnull
     public static final NgramContext EMPTY_PREV_WORDS_INFO =
             new NgramContext(WordInfo.EMPTY_WORD_INFO);
+    @Nonnull
     public static final NgramContext BEGINNING_OF_SENTENCE =
-            new NgramContext(WordInfo.BEGINNING_OF_SENTENCE);
+            new NgramContext(WordInfo.BEGINNING_OF_SENTENCE_WORD_INFO);
 
     /**
      * Word information used to represent previous words information.
      */
     public static class WordInfo {
+        @Nonnull
         public static final WordInfo EMPTY_WORD_INFO = new WordInfo(null);
-        public static final WordInfo BEGINNING_OF_SENTENCE = new WordInfo();
+        @Nonnull
+        public static final WordInfo BEGINNING_OF_SENTENCE_WORD_INFO = new WordInfo();
 
         // This is an empty char sequence when mIsBeginningOfSentence is true.
         public final CharSequence mWord;
@@ -48,7 +55,7 @@ public class NgramContext {
         public final boolean mIsBeginningOfSentence;
 
         // Beginning of sentence.
-        public WordInfo() {
+        private WordInfo() {
             mWord = "";
             mIsBeginningOfSentence = true;
         }
@@ -96,19 +103,8 @@ public class NgramContext {
         mPrevWordsCount = prevWordsInfo.length;
     }
 
-    // Construct from WordInfo array and size. The caller shouldn't change prevWordsInfo after
-    // calling this method.
-    private NgramContext(final NgramContext ngramContext, final int prevWordsCount) {
-        if (ngramContext.mPrevWordsCount < prevWordsCount) {
-            throw new IndexOutOfBoundsException("ngramContext.mPrevWordsCount ("
-                    + ngramContext.mPrevWordsCount + ") is smaller than prevWordsCount ("
-                    + prevWordsCount + ")");
-        }
-        mPrevWordsInfo = ngramContext.mPrevWordsInfo;
-        mPrevWordsCount = prevWordsCount;
-    }
-
     // Create next prevWordsInfo using current prevWordsInfo.
+    @Nonnull
     public NgramContext getNextNgramContext(final WordInfo wordInfo) {
         final int nextPrevWordCount = Math.min(Constants.MAX_PREV_WORD_COUNT_FOR_N_GRAM,
                 mPrevWordsCount + 1);