Change DictionaryFacilitator.java to an interface, create its

implementation DictionaryFacilitatorImpl.java and add a java-overridable
factory DictionaryFacilitatorProvider.java used to create a
DictionaryFacilitator.

Change-Id: Id4a58ae31feaa4d12a048a772c8d76ff82fdee45

1 files changed, 54 insertions, 832 deletions

diff --git a/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java b/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java
index b8893a5d8..a0a1d939e 100644
--- a/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java
+++ b/java/src/com/android/inputmethod/latin/DictionaryFacilitator.java
@@ -17,272 +17,58 @@
 package com.android.inputmethod.latin;
 
 import android.content.Context;
-import android.text.TextUtils;
-import android.util.Log;
-import android.util.Pair;
 import android.view.inputmethod.InputMethodSubtype;
+import android.util.Pair;
 
 import com.android.inputmethod.annotations.UsedForTesting;
 import com.android.inputmethod.latin.ExpandableBinaryDictionary.UpdateEntriesForInputEventsCallback;
-import com.android.inputmethod.latin.NgramContext.WordInfo;
-import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
-import com.android.inputmethod.latin.common.Constants;
-import com.android.inputmethod.latin.personalization.ContextualDictionary;
 import com.android.inputmethod.latin.personalization.PersonalizationDataChunk;
-import com.android.inputmethod.latin.personalization.PersonalizationDictionary;
-import com.android.inputmethod.latin.personalization.UserHistoryDictionary;
 import com.android.inputmethod.latin.settings.SettingsValuesForSuggestion;
 import com.android.inputmethod.latin.settings.SpacingAndPunctuations;
-import com.android.inputmethod.latin.utils.DistracterFilter;
-import com.android.inputmethod.latin.utils.DistracterFilterCheckingExactMatchesAndSuggestions;
-import com.android.inputmethod.latin.utils.DistracterFilterCheckingIsInDictionary;
-import com.android.inputmethod.latin.utils.ExecutorUtils;
 import com.android.inputmethod.latin.utils.SuggestionResults;
 
 import java.io.File;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
 import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
 import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
 import java.util.Locale;
+import java.util.List;
 import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
 /**
- * Facilitates interaction with different kinds of dictionaries. Provides APIs
- * to instantiate and select the correct dictionaries (based on language or account),
- * update entries and fetch suggestions.
- *
- * Currently AndroidSpellCheckerService and LatinIME both use DictionaryFacilitator as
- * a client for interacting with dictionaries.
+ * Interface that facilitates interaction with different kinds of dictionaries. Provides APIs to
+ * instantiate and select the correct dictionaries (based on language or account), update entries
+ * and fetch suggestions. Currently AndroidSpellCheckerService and LatinIME both use
+ * DictionaryFacilitator as a client for interacting with dictionaries.
  */
-public class DictionaryFacilitator {
-    // TODO: Consolidate dictionaries in native code.
-    public static final String TAG = DictionaryFacilitator.class.getSimpleName();
-
-    // HACK: This threshold is being used when adding a capitalized entry in the User History
-    // dictionary.
-    private static final int CAPITALIZED_FORM_MAX_PROBABILITY_FOR_INSERT = 140;
-    // How many words we need to type in a row ({@see mConfidenceInMostProbableLanguage}) to
-    // declare we are confident the user is typing in the most probable language.
-    private static final int CONFIDENCE_THRESHOLD = 3;
-
-    private DictionaryGroup[] mDictionaryGroups = new DictionaryGroup[] { new DictionaryGroup() };
-    private DictionaryGroup mMostProbableDictionaryGroup = mDictionaryGroups[0];
-    private boolean mIsUserDictEnabled = false;
-    private volatile CountDownLatch mLatchForWaitingLoadingMainDictionaries = new CountDownLatch(0);
-    // To synchronize assigning mDictionaryGroup to ensure closing dictionaries.
-    private final Object mLock = new Object();
-    private final DistracterFilter mDistracterFilter;
-    private final PersonalizationHelperForDictionaryFacilitator mPersonalizationHelper;
-
-    private static final String[] DICT_TYPES_ORDERED_TO_GET_SUGGESTIONS =
-            new String[] {
-                Dictionary.TYPE_MAIN,
-                Dictionary.TYPE_USER_HISTORY,
-                Dictionary.TYPE_PERSONALIZATION,
-                Dictionary.TYPE_USER,
-                Dictionary.TYPE_CONTACTS,
-                Dictionary.TYPE_CONTEXTUAL
-            };
-
-    public static final Map<String, Class<? extends ExpandableBinaryDictionary>>
-            DICT_TYPE_TO_CLASS = new HashMap<>();
-
-    static {
-        DICT_TYPE_TO_CLASS.put(Dictionary.TYPE_USER_HISTORY, UserHistoryDictionary.class);
-        DICT_TYPE_TO_CLASS.put(Dictionary.TYPE_PERSONALIZATION, PersonalizationDictionary.class);
-        DICT_TYPE_TO_CLASS.put(Dictionary.TYPE_USER, UserBinaryDictionary.class);
-        DICT_TYPE_TO_CLASS.put(Dictionary.TYPE_CONTACTS, ContactsBinaryDictionary.class);
-        DICT_TYPE_TO_CLASS.put(Dictionary.TYPE_CONTEXTUAL, ContextualDictionary.class);
-    }
-
-    private static final String DICT_FACTORY_METHOD_NAME = "getDictionary";
-    private static final Class<?>[] DICT_FACTORY_METHOD_ARG_TYPES =
-            new Class[] { Context.class, Locale.class, File.class, String.class, String.class };
-
-    private static final String[] SUB_DICT_TYPES =
-            Arrays.copyOfRange(DICT_TYPES_ORDERED_TO_GET_SUGGESTIONS, 1 /* start */,
-                    DICT_TYPES_ORDERED_TO_GET_SUGGESTIONS.length);
-
+public interface DictionaryFacilitator {
     /**
      * Returns whether this facilitator is exactly for this list of locales.
      *
      * @param locales the list of locales to test against
      */
-    public boolean isForLocales(final Locale[] locales) {
-        if (locales.length != mDictionaryGroups.length) {
-            return false;
-        }
-        for (final Locale locale : locales) {
-            boolean found = false;
-            for (final DictionaryGroup group : mDictionaryGroups) {
-                if (locale.equals(group.mLocale)) {
-                    found = true;
-                    break;
-                }
-            }
-            if (!found) {
-                return false;
-            }
-        }
-        return true;
-    }
+    boolean isForLocales(final Locale[] locales);
 
     /**
      * Returns whether this facilitator is exactly for this account.
      *
      * @param account the account to test against.
      */
-    public boolean isForAccount(@Nullable final String account) {
-        for (final DictionaryGroup group : mDictionaryGroups) {
-            if (!TextUtils.equals(group.mAccount, account)) {
-                return false;
-            }
-        }
-        return true;
-    }
+    boolean isForAccount(@Nullable final String account);
 
-    /**
-     * A group of dictionaries that work together for a single language.
-     */
-    private static class DictionaryGroup {
-        // TODO: Add null analysis annotations.
-        // TODO: Run evaluation to determine a reasonable value for these constants. The current
-        // values are ad-hoc and chosen without any particular care or methodology.
-        public static final float WEIGHT_FOR_MOST_PROBABLE_LANGUAGE = 1.0f;
-        public static final float WEIGHT_FOR_GESTURING_IN_NOT_MOST_PROBABLE_LANGUAGE = 0.95f;
-        public static final float WEIGHT_FOR_TYPING_IN_NOT_MOST_PROBABLE_LANGUAGE = 0.6f;
-
-        /**
-         * The locale associated with the dictionary group.
-         */
-        @Nullable public final Locale mLocale;
-
-        /**
-         * The user account associated with the dictionary group.
-         */
-        @Nullable public final String mAccount;
-
-        @Nullable private Dictionary mMainDict;
-        // Confidence that the most probable language is actually the language the user is
-        // typing in. For now, this is simply the number of times a word from this language
-        // has been committed in a row.
-        private int mConfidence = 0;
-
-        public float mWeightForTypingInLocale = WEIGHT_FOR_MOST_PROBABLE_LANGUAGE;
-        public float mWeightForGesturingInLocale = WEIGHT_FOR_MOST_PROBABLE_LANGUAGE;
-        public final ConcurrentHashMap<String, ExpandableBinaryDictionary> mSubDictMap =
-                new ConcurrentHashMap<>();
-
-        public DictionaryGroup() {
-            this(null /* locale */, null /* mainDict */, null /* account */,
-                    Collections.<String, ExpandableBinaryDictionary>emptyMap() /* subDicts */);
-        }
-
-        public DictionaryGroup(@Nullable final Locale locale,
-                @Nullable final Dictionary mainDict,
-                @Nullable final String account,
-                final Map<String, ExpandableBinaryDictionary> subDicts) {
-            mLocale = locale;
-            mAccount = account;
-            // The main dictionary can be asynchronously loaded.
-            setMainDict(mainDict);
-            for (final Map.Entry<String, ExpandableBinaryDictionary> entry : subDicts.entrySet()) {
-                setSubDict(entry.getKey(), entry.getValue());
-            }
-        }
-
-        private void setSubDict(final String dictType, final ExpandableBinaryDictionary dict) {
-            if (dict != null) {
-                mSubDictMap.put(dictType, dict);
-            }
-        }
-
-        public void setMainDict(final Dictionary mainDict) {
-            // Close old dictionary if exists. Main dictionary can be assigned multiple times.
-            final Dictionary oldDict = mMainDict;
-            mMainDict = mainDict;
-            if (oldDict != null && mainDict != oldDict) {
-                oldDict.close();
-            }
-        }
-
-        public Dictionary getDict(final String dictType) {
-            if (Dictionary.TYPE_MAIN.equals(dictType)) {
-                return mMainDict;
-            }
-            return getSubDict(dictType);
-        }
-
-        public ExpandableBinaryDictionary getSubDict(final String dictType) {
-            return mSubDictMap.get(dictType);
-        }
-
-        public boolean hasDict(final String dictType, @Nullable final String account) {
-            if (Dictionary.TYPE_MAIN.equals(dictType)) {
-                return mMainDict != null;
-            }
-            if (Dictionary.TYPE_USER_HISTORY.equals(dictType) &&
-                    !TextUtils.equals(account, mAccount)) {
-                // If the dictionary type is user history, & if the account doesn't match,
-                // return immediately. If the account matches, continue looking it up in the
-                // sub dictionary map.
-                return false;
-            }
-            return mSubDictMap.containsKey(dictType);
-        }
-
-        public void closeDict(final String dictType) {
-            final Dictionary dict;
-            if (Dictionary.TYPE_MAIN.equals(dictType)) {
-                dict = mMainDict;
-            } else {
-                dict = mSubDictMap.remove(dictType);
-            }
-            if (dict != null) {
-                dict.close();
-            }
-        }
+    interface DictionaryInitializationListener {
+        void onUpdateMainDictionaryAvailability(boolean isMainDictionaryAvailable);
     }
 
-    public interface DictionaryInitializationListener {
-        public void onUpdateMainDictionaryAvailability(boolean isMainDictionaryAvailable);
-    }
-
-    public DictionaryFacilitator() {
-        mDistracterFilter = DistracterFilter.EMPTY_DISTRACTER_FILTER;
-        mPersonalizationHelper = null;
-    }
-
-    public DictionaryFacilitator(final Context context) {
-        mDistracterFilter = new DistracterFilterCheckingExactMatchesAndSuggestions(context);
-        mPersonalizationHelper =
-                new PersonalizationHelperForDictionaryFacilitator(context, mDistracterFilter);
-    }
-
-    public void updateEnabledSubtypes(final List<InputMethodSubtype> enabledSubtypes) {
-        mDistracterFilter.updateEnabledSubtypes(enabledSubtypes);
-        mPersonalizationHelper.updateEnabledSubtypes(enabledSubtypes);
-    }
+    void updateEnabledSubtypes(final List<InputMethodSubtype> enabledSubtypes);
 
     // TODO: remove this, it's confusing with seamless multiple language switching
-    public void setIsMonolingualUser(final boolean isMonolingualUser) {
-        mPersonalizationHelper.setIsMonolingualUser(isMonolingualUser);
-    }
+    void setIsMonolingualUser(final boolean isMonolingualUser);
 
-    public boolean isActive() {
-        return null != mDictionaryGroups[0].mLocale;
-    }
+    boolean isActive();
 
     /**
      * Returns the most probable locale among all currently active locales. BE CAREFUL using this.
@@ -292,660 +78,96 @@ public class DictionaryFacilitator {
      * string.
      * @return the most probable locale
      */
-    public Locale getMostProbableLocale() {
-        return getDictionaryGroupForMostProbableLanguage().mLocale;
-    }
+    Locale getMostProbableLocale();
 
-    public Locale[] getLocales() {
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        final Locale[] locales = new Locale[dictionaryGroups.length];
-        for (int i = 0; i < dictionaryGroups.length; ++i) {
-            locales[i] = dictionaryGroups[i].mLocale;
-        }
-        return locales;
-    }
+    Locale[] getLocales();
 
-    private DictionaryGroup getDictionaryGroupForMostProbableLanguage() {
-        return mMostProbableDictionaryGroup;
-    }
+    void switchMostProbableLanguage(@Nullable final Locale locale);
 
-    public void switchMostProbableLanguage(@Nullable final Locale locale) {
-        if (null == locale) {
-            // In many cases, there is no locale to a committed word. For example, a typed word
-            // that is in none of the currently active dictionaries but still does not
-            // auto-correct to anything has no locale. In this case we simply do not change
-            // the most probable language and do not touch confidence.
-            return;
-        }
-        final DictionaryGroup newMostProbableDictionaryGroup =
-                findDictionaryGroupWithLocale(mDictionaryGroups, locale);
-        if (null == newMostProbableDictionaryGroup) {
-            // It seems this may happen as a race condition; pressing the globe key and space
-            // in quick succession could commit a word out of a dictionary that's not in the
-            // facilitator any more. In this case, just not changing things is fine.
-            return;
-        }
-        if (newMostProbableDictionaryGroup == mMostProbableDictionaryGroup) {
-            ++newMostProbableDictionaryGroup.mConfidence;
-        } else {
-            mMostProbableDictionaryGroup.mWeightForTypingInLocale =
-                    DictionaryGroup.WEIGHT_FOR_TYPING_IN_NOT_MOST_PROBABLE_LANGUAGE;
-            mMostProbableDictionaryGroup.mWeightForGesturingInLocale =
-                    DictionaryGroup.WEIGHT_FOR_GESTURING_IN_NOT_MOST_PROBABLE_LANGUAGE;
-            mMostProbableDictionaryGroup.mConfidence = 0;
-            newMostProbableDictionaryGroup.mWeightForTypingInLocale =
-                    DictionaryGroup.WEIGHT_FOR_MOST_PROBABLE_LANGUAGE;
-            newMostProbableDictionaryGroup.mWeightForGesturingInLocale =
-                    DictionaryGroup.WEIGHT_FOR_MOST_PROBABLE_LANGUAGE;
-            mMostProbableDictionaryGroup = newMostProbableDictionaryGroup;
-        }
-    }
+    boolean isConfidentAboutCurrentLanguageBeing(final Locale mLocale);
 
-    public boolean isConfidentAboutCurrentLanguageBeing(final Locale mLocale) {
-        final DictionaryGroup mostProbableDictionaryGroup = mMostProbableDictionaryGroup;
-        if (!mostProbableDictionaryGroup.mLocale.equals(mLocale)) {
-            return false;
-        }
-        if (mDictionaryGroups.length <= 1) {
-            return true;
-        }
-        return mostProbableDictionaryGroup.mConfidence >= CONFIDENCE_THRESHOLD;
-    }
-
-    @Nullable
-    private static ExpandableBinaryDictionary getSubDict(final String dictType,
-            final Context context, final Locale locale, final File dictFile,
-            final String dictNamePrefix, @Nullable final String account) {
-        final Class<? extends ExpandableBinaryDictionary> dictClass =
-                DICT_TYPE_TO_CLASS.get(dictType);
-        if (dictClass == null) {
-            return null;
-        }
-        try {
-            final Method factoryMethod = dictClass.getMethod(DICT_FACTORY_METHOD_NAME,
-                    DICT_FACTORY_METHOD_ARG_TYPES);
-            final Object dict = factoryMethod.invoke(null /* obj */,
-                    new Object[] { context, locale, dictFile, dictNamePrefix, account });
-            return (ExpandableBinaryDictionary) dict;
-        } catch (final NoSuchMethodException | SecurityException | IllegalAccessException
-                | IllegalArgumentException | InvocationTargetException e) {
-            Log.e(TAG, "Cannot create dictionary: " + dictType, e);
-            return null;
-        }
-    }
-
-    public void resetDictionaries(final Context context, final Locale[] newLocales,
+    void resetDictionaries(final Context context, final Locale[] newLocales,
             final boolean useContactsDict, final boolean usePersonalizedDicts,
             final boolean forceReloadMainDictionary,
             @Nullable final String account,
-            final DictionaryInitializationListener listener) {
-        resetDictionariesWithDictNamePrefix(context, newLocales, useContactsDict,
-                usePersonalizedDicts, forceReloadMainDictionary, listener, "" /* dictNamePrefix */,
-                account);
-    }
+            final DictionaryInitializationListener listener);
 
-    @Nullable
-    static DictionaryGroup findDictionaryGroupWithLocale(final DictionaryGroup[] dictionaryGroups,
-            final Locale locale) {
-        for (DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            if (locale.equals(dictionaryGroup.mLocale)) {
-                return dictionaryGroup;
-            }
-        }
-        return null;
-    }
-
-    public void resetDictionariesWithDictNamePrefix(final Context context,
+    void resetDictionariesWithDictNamePrefix(final Context context,
             final Locale[] newLocales,
             final boolean useContactsDict,
             final boolean usePersonalizedDicts,
             final boolean forceReloadMainDictionary,
             @Nullable final DictionaryInitializationListener listener,
             final String dictNamePrefix,
-            @Nullable final String account) {
-        final HashMap<Locale, ArrayList<String>> existingDictionariesToCleanup = new HashMap<>();
-        // TODO: Make subDictTypesToUse configurable by resource or a static final list.
-        final HashSet<String> subDictTypesToUse = new HashSet<>();
-        subDictTypesToUse.add(Dictionary.TYPE_USER);
-        if (useContactsDict) {
-            subDictTypesToUse.add(Dictionary.TYPE_CONTACTS);
-        }
-        if (usePersonalizedDicts) {
-            subDictTypesToUse.add(Dictionary.TYPE_USER_HISTORY);
-            subDictTypesToUse.add(Dictionary.TYPE_PERSONALIZATION);
-            subDictTypesToUse.add(Dictionary.TYPE_CONTEXTUAL);
-        }
-
-        // Gather all dictionaries. We'll remove them from the list to clean up later.
-        for (final Locale newLocale : newLocales) {
-            final ArrayList<String> dictTypeForLocale = new ArrayList<>();
-            existingDictionariesToCleanup.put(newLocale, dictTypeForLocale);
-            final DictionaryGroup currentDictionaryGroupForLocale =
-                    findDictionaryGroupWithLocale(mDictionaryGroups, newLocale);
-            if (null == currentDictionaryGroupForLocale) {
-                continue;
-            }
-            for (final String dictType : SUB_DICT_TYPES) {
-                if (currentDictionaryGroupForLocale.hasDict(dictType, account)) {
-                    dictTypeForLocale.add(dictType);
-                }
-            }
-            if (currentDictionaryGroupForLocale.hasDict(Dictionary.TYPE_MAIN, account)) {
-                dictTypeForLocale.add(Dictionary.TYPE_MAIN);
-            }
-        }
-
-        final DictionaryGroup[] newDictionaryGroups = new DictionaryGroup[newLocales.length];
-        for (int i = 0; i < newLocales.length; ++i) {
-            final Locale newLocale = newLocales[i];
-            final DictionaryGroup dictionaryGroupForLocale =
-                    findDictionaryGroupWithLocale(mDictionaryGroups, newLocale);
-            final ArrayList<String> dictTypesToCleanupForLocale =
-                    existingDictionariesToCleanup.get(newLocale);
-            final boolean noExistingDictsForThisLocale = (null == dictionaryGroupForLocale);
-
-            final Dictionary mainDict;
-            if (forceReloadMainDictionary || noExistingDictsForThisLocale
-                    || !dictionaryGroupForLocale.hasDict(Dictionary.TYPE_MAIN, account)) {
-                mainDict = null;
-            } else {
-                mainDict = dictionaryGroupForLocale.getDict(Dictionary.TYPE_MAIN);
-                dictTypesToCleanupForLocale.remove(Dictionary.TYPE_MAIN);
-            }
-
-            final Map<String, ExpandableBinaryDictionary> subDicts = new HashMap<>();
-            for (final String subDictType : subDictTypesToUse) {
-                final ExpandableBinaryDictionary subDict;
-                if (noExistingDictsForThisLocale
-                        || !dictionaryGroupForLocale.hasDict(subDictType, account)) {
-                    // Create a new dictionary.
-                    subDict = getSubDict(subDictType, context, newLocale, null /* dictFile */,
-                            dictNamePrefix, account);
-                } else {
-                    // Reuse the existing dictionary, and don't close it at the end
-                    subDict = dictionaryGroupForLocale.getSubDict(subDictType);
-                    dictTypesToCleanupForLocale.remove(subDictType);
-                }
-                subDicts.put(subDictType, subDict);
-            }
-            newDictionaryGroups[i] = new DictionaryGroup(newLocale, mainDict, account, subDicts);
-        }
-
-        // Replace Dictionaries.
-        final DictionaryGroup[] oldDictionaryGroups;
-        synchronized (mLock) {
-            oldDictionaryGroups = mDictionaryGroups;
-            mDictionaryGroups = newDictionaryGroups;
-            mMostProbableDictionaryGroup = newDictionaryGroups[0];
-            mIsUserDictEnabled = UserBinaryDictionary.isEnabled(context);
-            if (hasAtLeastOneUninitializedMainDictionary()) {
-                asyncReloadUninitializedMainDictionaries(context, newLocales, listener);
-            }
-        }
-        if (listener != null) {
-            listener.onUpdateMainDictionaryAvailability(hasAtLeastOneInitializedMainDictionary());
-        }
-
-        // Clean up old dictionaries.
-        for (final Locale localeToCleanUp : existingDictionariesToCleanup.keySet()) {
-            final ArrayList<String> dictTypesToCleanUp =
-                    existingDictionariesToCleanup.get(localeToCleanUp);
-            final DictionaryGroup dictionarySetToCleanup =
-                    findDictionaryGroupWithLocale(oldDictionaryGroups, localeToCleanUp);
-            for (final String dictType : dictTypesToCleanUp) {
-                dictionarySetToCleanup.closeDict(dictType);
-            }
-        }
-    }
-
-    private void asyncReloadUninitializedMainDictionaries(final Context context,
-            final Locale[] locales, final DictionaryInitializationListener listener) {
-        final CountDownLatch latchForWaitingLoadingMainDictionary = new CountDownLatch(1);
-        mLatchForWaitingLoadingMainDictionaries = latchForWaitingLoadingMainDictionary;
-        ExecutorUtils.getExecutor("InitializeBinaryDictionary").execute(new Runnable() {
-            @Override
-            public void run() {
-                doReloadUninitializedMainDictionaries(
-                        context, locales, listener, latchForWaitingLoadingMainDictionary);
-            }
-        });
-    }
-
-    void doReloadUninitializedMainDictionaries(final Context context, final Locale[] locales,
-            final DictionaryInitializationListener listener,
-            final CountDownLatch latchForWaitingLoadingMainDictionary) {
-        for (final Locale locale : locales) {
-            final DictionaryGroup dictionaryGroup =
-                    findDictionaryGroupWithLocale(mDictionaryGroups, locale);
-            if (null == dictionaryGroup) {
-                // This should never happen, but better safe than crashy
-                Log.w(TAG, "Expected a dictionary group for " + locale + " but none found");
-                continue;
-            }
-            final Dictionary mainDict =
-                    DictionaryFactory.createMainDictionaryFromManager(context, locale);
-            synchronized (mLock) {
-                if (locale.equals(dictionaryGroup.mLocale)) {
-                    dictionaryGroup.setMainDict(mainDict);
-                } else {
-                    // Dictionary facilitator has been reset for another locale.
-                    mainDict.close();
-                }
-            }
-        }
-        if (listener != null) {
-            listener.onUpdateMainDictionaryAvailability(
-                    hasAtLeastOneInitializedMainDictionary());
-        }
-        latchForWaitingLoadingMainDictionary.countDown();
-    }
+            @Nullable final String account);
 
     @UsedForTesting
-    public void resetDictionariesForTesting(final Context context, final Locale[] locales,
+    void resetDictionariesForTesting(final Context context, final Locale[] locales,
             final ArrayList<String> dictionaryTypes, final HashMap<String, File> dictionaryFiles,
             final Map<String, Map<String, String>> additionalDictAttributes,
-            @Nullable final String account) {
-        Dictionary mainDictionary = null;
-        final Map<String, ExpandableBinaryDictionary> subDicts = new HashMap<>();
-
-        final DictionaryGroup[] dictionaryGroups = new DictionaryGroup[locales.length];
-        for (int i = 0; i < locales.length; ++i) {
-            final Locale locale = locales[i];
-            for (final String dictType : dictionaryTypes) {
-                if (dictType.equals(Dictionary.TYPE_MAIN)) {
-                    mainDictionary = DictionaryFactory.createMainDictionaryFromManager(context,
-                            locale);
-                } else {
-                    final File dictFile = dictionaryFiles.get(dictType);
-                    final ExpandableBinaryDictionary dict = getSubDict(
-                            dictType, context, locale, dictFile, "" /* dictNamePrefix */, account);
-                    if (additionalDictAttributes.containsKey(dictType)) {
-                        dict.clearAndFlushDictionaryWithAdditionalAttributes(
-                                additionalDictAttributes.get(dictType));
-                    }
-                    if (dict == null) {
-                        throw new RuntimeException("Unknown dictionary type: " + dictType);
-                    }
-                    dict.reloadDictionaryIfRequired();
-                    dict.waitAllTasksForTests();
-                    subDicts.put(dictType, dict);
-                }
-            }
-            dictionaryGroups[i] = new DictionaryGroup(locale, mainDictionary, account, subDicts);
-        }
-        mDictionaryGroups = dictionaryGroups;
-        mMostProbableDictionaryGroup = dictionaryGroups[0];
-    }
+            @Nullable final String account);
 
-    public void closeDictionaries() {
-        final DictionaryGroup[] dictionaryGroups;
-        synchronized (mLock) {
-            dictionaryGroups = mDictionaryGroups;
-            mMostProbableDictionaryGroup = new DictionaryGroup();
-            mDictionaryGroups = new DictionaryGroup[] { mMostProbableDictionaryGroup };
-        }
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            for (final String dictType : DICT_TYPES_ORDERED_TO_GET_SUGGESTIONS) {
-                dictionaryGroup.closeDict(dictType);
-            }
-        }
-        mDistracterFilter.close();
-        if (mPersonalizationHelper != null) {
-            mPersonalizationHelper.close();
-        }
-    }
+    void closeDictionaries();
 
     @UsedForTesting
-    public ExpandableBinaryDictionary getSubDictForTesting(final String dictName) {
-        return mMostProbableDictionaryGroup.getSubDict(dictName);
-    }
+    ExpandableBinaryDictionary getSubDictForTesting(final String dictName);
 
-    // The main dictionaries are loaded asynchronously.  Don't cache the return value
+    // The main dictionaries are loaded asynchronously. Don't cache the return value
     // of these methods.
-    public boolean hasAtLeastOneInitializedMainDictionary() {
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            final Dictionary mainDict = dictionaryGroup.getDict(Dictionary.TYPE_MAIN);
-            if (mainDict != null && mainDict.isInitialized()) {
-                return true;
-            }
-        }
-        return false;
-    }
+    boolean hasAtLeastOneInitializedMainDictionary();
 
-    public boolean hasAtLeastOneUninitializedMainDictionary() {
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            final Dictionary mainDict = dictionaryGroup.getDict(Dictionary.TYPE_MAIN);
-            if (mainDict == null || !mainDict.isInitialized()) {
-                return true;
-            }
-        }
-        return false;
-    }
+    boolean hasAtLeastOneUninitializedMainDictionary();
 
-    public boolean hasPersonalizationDictionary() {
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            if (dictionaryGroup.hasDict(Dictionary.TYPE_PERSONALIZATION, null /* account */)) {
-                return true;
-            }
-        }
-        return false;
-    }
+    boolean hasPersonalizationDictionary();
 
-    public void flushPersonalizationDictionary() {
-        final HashSet<ExpandableBinaryDictionary> personalizationDictsUsedForSuggestion =
-                new HashSet<>();
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            final ExpandableBinaryDictionary personalizationDictUsedForSuggestion =
-                    dictionaryGroup.getSubDict(Dictionary.TYPE_PERSONALIZATION);
-            personalizationDictsUsedForSuggestion.add(personalizationDictUsedForSuggestion);
-        }
-        mPersonalizationHelper.flushPersonalizationDictionariesToUpdate(
-                personalizationDictsUsedForSuggestion);
-        mDistracterFilter.close();
-    }
+    void flushPersonalizationDictionary();
 
-    public void waitForLoadingMainDictionaries(final long timeout, final TimeUnit unit)
-            throws InterruptedException {
-        mLatchForWaitingLoadingMainDictionaries.await(timeout, unit);
-    }
+    void waitForLoadingMainDictionaries(final long timeout, final TimeUnit unit)
+            throws InterruptedException;
 
     @UsedForTesting
-    public void waitForLoadingDictionariesForTesting(final long timeout, final TimeUnit unit)
-            throws InterruptedException {
-        waitForLoadingMainDictionaries(timeout, unit);
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            for (final ExpandableBinaryDictionary dict : dictionaryGroup.mSubDictMap.values()) {
-                dict.waitAllTasksForTests();
-            }
-        }
-    }
+    void waitForLoadingDictionariesForTesting(final long timeout, final TimeUnit unit)
+            throws InterruptedException;
 
-    public boolean isUserDictionaryEnabled() {
-        return mIsUserDictEnabled;
-    }
+    boolean isUserDictionaryEnabled();
 
-    public void addWordToUserDictionary(final Context context, final String word) {
-        final Locale locale = getMostProbableLocale();
-        if (locale == null) {
-            return;
-        }
-        // TODO: add a toast telling what language this is being added to?
-        UserBinaryDictionary.addWordToUserDictionary(context, locale, word);
-    }
+    void addWordToUserDictionary(final Context context, final String word);
 
-    public void addToUserHistory(final String suggestion, final boolean wasAutoCapitalized,
+    void addToUserHistory(final String suggestion, final boolean wasAutoCapitalized,
             @Nonnull final NgramContext ngramContext, final int timeStampInSeconds,
-            final boolean blockPotentiallyOffensive) {
-        final DictionaryGroup dictionaryGroup = getDictionaryGroupForMostProbableLanguage();
-        final String[] words = suggestion.split(Constants.WORD_SEPARATOR);
-        NgramContext ngramContextForCurrentWord = ngramContext;
-        for (int i = 0; i < words.length; i++) {
-            final String currentWord = words[i];
-            final boolean wasCurrentWordAutoCapitalized = (i == 0) ? wasAutoCapitalized : false;
-            addWordToUserHistory(dictionaryGroup, ngramContextForCurrentWord, currentWord,
-                    wasCurrentWordAutoCapitalized, timeStampInSeconds, blockPotentiallyOffensive);
-            ngramContextForCurrentWord =
-                    ngramContextForCurrentWord.getNextNgramContext(new WordInfo(currentWord));
-        }
-    }
-
-    private void addWordToUserHistory(final DictionaryGroup dictionaryGroup,
-            final NgramContext ngramContext, final String word, final boolean wasAutoCapitalized,
-            final int timeStampInSeconds, final boolean blockPotentiallyOffensive) {
-        final ExpandableBinaryDictionary userHistoryDictionary =
-                dictionaryGroup.getSubDict(Dictionary.TYPE_USER_HISTORY);
-        if (userHistoryDictionary == null
-                || !isConfidentAboutCurrentLanguageBeing(userHistoryDictionary.mLocale)) {
-            return;
-        }
-        final int maxFreq = getFrequency(word);
-        if (maxFreq == 0 && blockPotentiallyOffensive) {
-            return;
-        }
-        final String lowerCasedWord = word.toLowerCase(dictionaryGroup.mLocale);
-        final String secondWord;
-        if (wasAutoCapitalized) {
-            if (isValidWord(word, false /* ignoreCase */)
-                    && !isValidWord(lowerCasedWord, false /* ignoreCase */)) {
-                // If the word was auto-capitalized and exists only as a capitalized word in the
-                // dictionary, then we must not downcase it before registering it. For example,
-                // the name of the contacts in start-of-sentence position would come here with the
-                // wasAutoCapitalized flag: if we downcase it, we'd register a lower-case version
-                // of that contact's name which would end up popping in suggestions.
-                secondWord = word;
-            } else {
-                // If however the word is not in the dictionary, or exists as a lower-case word
-                // only, then we consider that was a lower-case word that had been auto-capitalized.
-                secondWord = lowerCasedWord;
-            }
-        } else {
-            // HACK: We'd like to avoid adding the capitalized form of common words to the User
-            // History dictionary in order to avoid suggesting them until the dictionary
-            // consolidation is done.
-            // TODO: Remove this hack when ready.
-            final int lowerCaseFreqInMainDict = dictionaryGroup.hasDict(Dictionary.TYPE_MAIN,
-                    null /* account */) ?
-                    dictionaryGroup.getDict(Dictionary.TYPE_MAIN).getFrequency(lowerCasedWord) :
-                            Dictionary.NOT_A_PROBABILITY;
-            if (maxFreq < lowerCaseFreqInMainDict
-                    && lowerCaseFreqInMainDict >= CAPITALIZED_FORM_MAX_PROBABILITY_FOR_INSERT) {
-                // Use lower cased word as the word can be a distracter of the popular word.
-                secondWord = lowerCasedWord;
-            } else {
-                secondWord = word;
-            }
-        }
-        // We demote unrecognized words (frequency < 0, below) by specifying them as "invalid".
-        // We don't add words with 0-frequency (assuming they would be profanity etc.).
-        final boolean isValid = maxFreq > 0;
-        UserHistoryDictionary.addToDictionary(userHistoryDictionary, ngramContext, secondWord,
-                isValid, timeStampInSeconds,
-                new DistracterFilterCheckingIsInDictionary(
-                        mDistracterFilter, userHistoryDictionary));
-    }
+            final boolean blockPotentiallyOffensive);
 
-    private void removeWord(final String dictName, final String word) {
-        final ExpandableBinaryDictionary dictionary =
-                getDictionaryGroupForMostProbableLanguage().getSubDict(dictName);
-        if (dictionary != null) {
-            dictionary.removeUnigramEntryDynamically(word);
-        }
-    }
-
-    public void removeWordFromPersonalizedDicts(final String word) {
-        removeWord(Dictionary.TYPE_USER_HISTORY, word);
-        removeWord(Dictionary.TYPE_PERSONALIZATION, word);
-        removeWord(Dictionary.TYPE_CONTEXTUAL, word);
-    }
+    void removeWordFromPersonalizedDicts(final String word);
 
     // TODO: Revise the way to fusion suggestion results.
-    public SuggestionResults getSuggestionResults(final WordComposer composer,
+    SuggestionResults getSuggestionResults(final WordComposer composer,
             final NgramContext ngramContext, final long proximityInfoHandle,
-            final SettingsValuesForSuggestion settingsValuesForSuggestion, final int sessionId) {
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        final SuggestionResults suggestionResults = new SuggestionResults(
-                SuggestedWords.MAX_SUGGESTIONS, ngramContext.isBeginningOfSentenceContext());
-        final float[] weightOfLangModelVsSpatialModel =
-                new float[] { Dictionary.NOT_A_WEIGHT_OF_LANG_MODEL_VS_SPATIAL_MODEL };
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            for (final String dictType : DICT_TYPES_ORDERED_TO_GET_SUGGESTIONS) {
-                final Dictionary dictionary = dictionaryGroup.getDict(dictType);
-                if (null == dictionary) continue;
-                final float weightForLocale = composer.isBatchMode()
-                        ? dictionaryGroup.mWeightForGesturingInLocale
-                        : dictionaryGroup.mWeightForTypingInLocale;
-                final ArrayList<SuggestedWordInfo> dictionarySuggestions =
-                        dictionary.getSuggestions(composer.getComposedDataSnapshot(), ngramContext,
-                                proximityInfoHandle, settingsValuesForSuggestion, sessionId,
-                                weightForLocale, weightOfLangModelVsSpatialModel);
-                if (null == dictionarySuggestions) continue;
-                suggestionResults.addAll(dictionarySuggestions);
-                if (null != suggestionResults.mRawSuggestions) {
-                    suggestionResults.mRawSuggestions.addAll(dictionarySuggestions);
-                }
-            }
-        }
-        return suggestionResults;
-    }
+            final SettingsValuesForSuggestion settingsValuesForSuggestion, final int sessionId);
 
-    public boolean isValidWord(final String word, final boolean ignoreCase) {
-        if (TextUtils.isEmpty(word)) {
-            return false;
-        }
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            if (dictionaryGroup.mLocale == null) {
-                continue;
-            }
-            final String lowerCasedWord = word.toLowerCase(dictionaryGroup.mLocale);
-            for (final String dictType : DICT_TYPES_ORDERED_TO_GET_SUGGESTIONS) {
-                final Dictionary dictionary = dictionaryGroup.getDict(dictType);
-                // Ideally the passed map would come out of a {@link java.util.concurrent.Future} and
-                // would be immutable once it's finished initializing, but concretely a null test is
-                // probably good enough for the time being.
-                if (null == dictionary) continue;
-                if (dictionary.isValidWord(word)
-                        || (ignoreCase && dictionary.isValidWord(lowerCasedWord))) {
-                    return true;
-                }
-            }
-        }
-        return false;
-    }
+    boolean isValidWord(final String word, final boolean ignoreCase);
 
-    private int getFrequencyInternal(final String word,
-            final boolean isGettingMaxFrequencyOfExactMatches) {
-        if (TextUtils.isEmpty(word)) {
-            return Dictionary.NOT_A_PROBABILITY;
-        }
-        int maxFreq = Dictionary.NOT_A_PROBABILITY;
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            for (final String dictType : DICT_TYPES_ORDERED_TO_GET_SUGGESTIONS) {
-                final Dictionary dictionary = dictionaryGroup.getDict(dictType);
-                if (dictionary == null) continue;
-                final int tempFreq;
-                if (isGettingMaxFrequencyOfExactMatches) {
-                    tempFreq = dictionary.getMaxFrequencyOfExactMatches(word);
-                } else {
-                    tempFreq = dictionary.getFrequency(word);
-                }
-                if (tempFreq >= maxFreq) {
-                    maxFreq = tempFreq;
-                }
-            }
-        }
-        return maxFreq;
-    }
+    int getFrequency(final String word);
 
-    public int getFrequency(final String word) {
-        return getFrequencyInternal(word, false /* isGettingMaxFrequencyOfExactMatches */);
-    }
-
-    public int getMaxFrequencyOfExactMatches(final String word) {
-        return getFrequencyInternal(word, true /* isGettingMaxFrequencyOfExactMatches */);
-    }
+    int getMaxFrequencyOfExactMatches(final String word);
 
-    private void clearSubDictionary(final String dictName) {
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            final ExpandableBinaryDictionary dictionary = dictionaryGroup.getSubDict(dictName);
-            if (dictionary != null) {
-                dictionary.clear();
-            }
-        }
-    }
-
-    public void clearUserHistoryDictionary() {
-        clearSubDictionary(Dictionary.TYPE_USER_HISTORY);
-    }
+    void clearUserHistoryDictionary();
 
     // This method gets called only when the IME receives a notification to remove the
     // personalization dictionary.
-    public void clearPersonalizationDictionary() {
-        clearSubDictionary(Dictionary.TYPE_PERSONALIZATION);
-        mPersonalizationHelper.clearDictionariesToUpdate();
-    }
+    void clearPersonalizationDictionary();
 
-    public void clearContextualDictionary() {
-        clearSubDictionary(Dictionary.TYPE_CONTEXTUAL);
-    }
+    void clearContextualDictionary();
 
-    public void addEntriesToPersonalizationDictionary(
+    void addEntriesToPersonalizationDictionary(
             final PersonalizationDataChunk personalizationDataChunk,
             final SpacingAndPunctuations spacingAndPunctuations,
-            final UpdateEntriesForInputEventsCallback callback) {
-        mPersonalizationHelper.updateEntriesOfPersonalizationDictionaries(
-                getMostProbableLocale(), personalizationDataChunk, spacingAndPunctuations,
-                callback);
-    }
+            final UpdateEntriesForInputEventsCallback callback);
 
     @UsedForTesting
-    public void addPhraseToContextualDictionary(final String[] phrase, final int probability,
-            final int bigramProbabilityForWords, final int bigramProbabilityForPhrases) {
-        // TODO: we're inserting the phrase into the dictionary for the active language. Rethink
-        // this a bit from a theoretical point of view.
-        final ExpandableBinaryDictionary contextualDict =
-                getDictionaryGroupForMostProbableLanguage().getSubDict(Dictionary.TYPE_CONTEXTUAL);
-        if (contextualDict == null) {
-            return;
-        }
-        NgramContext ngramContext = NgramContext.BEGINNING_OF_SENTENCE;
-        for (int i = 0; i < phrase.length; i++) {
-            final String[] subPhrase = Arrays.copyOfRange(phrase, i /* start */, phrase.length);
-            final String subPhraseStr = TextUtils.join(Constants.WORD_SEPARATOR, subPhrase);
-            contextualDict.addUnigramEntryWithCheckingDistracter(
-                    subPhraseStr, probability, null /* shortcutTarget */,
-                    Dictionary.NOT_A_PROBABILITY /* shortcutFreq */,
-                    false /* isNotAWord */, false /* isPossiblyOffensive */,
-                    BinaryDictionary.NOT_A_VALID_TIMESTAMP,
-                    DistracterFilter.EMPTY_DISTRACTER_FILTER);
-            contextualDict.addNgramEntry(ngramContext, subPhraseStr,
-                    bigramProbabilityForPhrases, BinaryDictionary.NOT_A_VALID_TIMESTAMP);
-
-            if (i < phrase.length - 1) {
-                contextualDict.addUnigramEntryWithCheckingDistracter(
-                        phrase[i], probability, null /* shortcutTarget */,
-                        Dictionary.NOT_A_PROBABILITY /* shortcutFreq */,
-                        false /* isNotAWord */, false /* isPossiblyOffensive */,
-                        BinaryDictionary.NOT_A_VALID_TIMESTAMP,
-                        DistracterFilter.EMPTY_DISTRACTER_FILTER);
-                contextualDict.addNgramEntry(ngramContext, phrase[i],
-                        bigramProbabilityForWords, BinaryDictionary.NOT_A_VALID_TIMESTAMP);
-            }
-            ngramContext =
-                    ngramContext.getNextNgramContext(new NgramContext.WordInfo(phrase[i]));
-        }
-    }
+    void addPhraseToContextualDictionary(final String[] phrase, final int probability,
+            final int bigramProbabilityForWords, final int bigramProbabilityForPhrases);
 
-    public void dumpDictionaryForDebug(final String dictName) {
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            final ExpandableBinaryDictionary dictToDump = dictionaryGroup.getSubDict(dictName);
-            if (dictToDump == null) {
-                Log.e(TAG, "Cannot dump " + dictName + ". "
-                        + "The dictionary is not being used for suggestion or cannot be dumped.");
-                return;
-            }
-            dictToDump.dumpAllWordsForDebug();
-        }
-    }
+    void dumpDictionaryForDebug(final String dictName);
 
-    public ArrayList<Pair<String, DictionaryStats>> getStatsOfEnabledSubDicts() {
-        final ArrayList<Pair<String, DictionaryStats>> statsOfEnabledSubDicts = new ArrayList<>();
-        final DictionaryGroup[] dictionaryGroups = mDictionaryGroups;
-        for (final DictionaryGroup dictionaryGroup : dictionaryGroups) {
-            for (final String dictType : SUB_DICT_TYPES) {
-                final ExpandableBinaryDictionary dictionary = dictionaryGroup.getSubDict(dictType);
-                if (dictionary == null) continue;
-                statsOfEnabledSubDicts.add(new Pair<>(dictType, dictionary.getDictionaryStats()));
-            }
-        }
-        return statsOfEnabledSubDicts;
-    }
+    ArrayList<Pair<String, DictionaryStats>> getStatsOfEnabledSubDicts();
 }