Make spell checker use dictionary facilitator.

Bug: 13630847
Change-Id: I07d17ccf5ce0755f63a0b8d236d77600baaf62b6

6 files changed, 236 insertions, 537 deletions

diff --git a/java/src/com/android/inputmethod/latin/spellcheck/AndroidSpellCheckerService.java b/java/src/com/android/inputmethod/latin/spellcheck/AndroidSpellCheckerService.java
index 90c8f618f..72b503138 100644
--- a/java/src/com/android/inputmethod/latin/spellcheck/AndroidSpellCheckerService.java
+++ b/java/src/com/android/inputmethod/latin/spellcheck/AndroidSpellCheckerService.java
@@ -16,22 +16,31 @@
 
 package com.android.inputmethod.latin.spellcheck;
 
+import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.preference.PreferenceManager;
 import android.service.textservice.SpellCheckerService;
 import android.text.InputType;
 import android.util.Log;
+import android.util.LruCache;
 import android.view.inputmethod.EditorInfo;
 import android.view.inputmethod.InputMethodSubtype;
 import android.view.textservice.SuggestionsInfo;
 
+import com.android.inputmethod.keyboard.Keyboard;
+import com.android.inputmethod.keyboard.KeyboardId;
 import com.android.inputmethod.keyboard.KeyboardLayoutSet;
+import com.android.inputmethod.keyboard.ProximityInfo;
 import com.android.inputmethod.latin.ContactsBinaryDictionary;
 import com.android.inputmethod.latin.Dictionary;
 import com.android.inputmethod.latin.DictionaryCollection;
+import com.android.inputmethod.latin.DictionaryFacilitator;
 import com.android.inputmethod.latin.DictionaryFactory;
+import com.android.inputmethod.latin.PrevWordsInfo;
 import com.android.inputmethod.latin.R;
+import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
+import com.android.inputmethod.latin.settings.SettingsValuesForSuggestion;
 import com.android.inputmethod.latin.UserBinaryDictionary;
 import com.android.inputmethod.latin.utils.AdditionalSubtypeUtils;
 import com.android.inputmethod.latin.utils.BinaryDictionaryUtils;
@@ -39,15 +48,23 @@ import com.android.inputmethod.latin.utils.CollectionUtils;
 import com.android.inputmethod.latin.utils.LocaleUtils;
 import com.android.inputmethod.latin.utils.ScriptUtils;
 import com.android.inputmethod.latin.utils.StringUtils;
+import com.android.inputmethod.latin.utils.SuggestionResults;
+import com.android.inputmethod.latin.WordComposer;
 
 import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Locale;
 import java.util.Map;
+import java.util.TreeMap;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Service for spell checking, using LatinIME's dictionaries and mechanisms.
@@ -56,31 +73,79 @@ public final class AndroidSpellCheckerService extends SpellCheckerService
         implements SharedPreferences.OnSharedPreferenceChangeListener {
     private static final String TAG = AndroidSpellCheckerService.class.getSimpleName();
     private static final boolean DBG = false;
-    private static final int POOL_SIZE = 2;
 
     public static final String PREF_USE_CONTACTS_KEY = "pref_spellcheck_use_contacts";
 
     private static final int SPELLCHECKER_DUMMY_KEYBOARD_WIDTH = 480;
     private static final int SPELLCHECKER_DUMMY_KEYBOARD_HEIGHT = 368;
 
-    private final static String[] EMPTY_STRING_ARRAY = new String[0];
-    private Map<String, DictionaryPool> mDictionaryPools = CollectionUtils.newSynchronizedTreeMap();
-    private Map<String, UserBinaryDictionary> mUserDictionaries =
-            CollectionUtils.newSynchronizedTreeMap();
-    private ContactsBinaryDictionary mContactsDictionary;
+    private static final String DICTIONARY_NAME_PREFIX = "spellcheck_";
+    private static final int WAIT_FOR_LOADING_MAIN_DICT_IN_MILLISECONDS = 1000;
+    private static final int MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT = 5;
+
+    private static final String[] EMPTY_STRING_ARRAY = new String[0];
+
+    private final HashSet<Locale> mCachedLocales = new HashSet<>();
+
+    private final int MAX_NUM_OF_THREADS_READ_DICTIONARY = 2;
+    private final Semaphore mSemaphore = new Semaphore(MAX_NUM_OF_THREADS_READ_DICTIONARY,
+            true /* fair */);
+    // TODO: Make each spell checker session has its own session id.
+    private final ConcurrentLinkedQueue<Integer> mSessionIdPool = new ConcurrentLinkedQueue<>();
+
+    private static class DictionaryFacilitatorLruCache extends
+            LruCache<Locale, DictionaryFacilitator> {
+        private final HashSet<Locale> mCachedLocales;
+        public DictionaryFacilitatorLruCache(final HashSet<Locale> cachedLocales, int maxSize) {
+            super(maxSize);
+            mCachedLocales = cachedLocales;
+        }
+
+        @Override
+        protected void entryRemoved(boolean evicted, Locale key,
+                DictionaryFacilitator oldValue, DictionaryFacilitator newValue) {
+            if (oldValue != null && oldValue != newValue) {
+                oldValue.closeDictionaries();
+            }
+            if (key != null && newValue == null) {
+                // Remove locale from the cache when the dictionary facilitator for the locale is
+                // evicted and new facilitator is not set for the locale.
+                mCachedLocales.remove(key);
+                if (size() >= maxSize()) {
+                    Log.w(TAG, "DictionaryFacilitator for " + key.toString()
+                            + " has been evicted due to cache size limit."
+                            + " size: " + size() + ", maxSize: " + maxSize());
+                }
+            }
+        }
+    }
+
+    private static final int MAX_DICTIONARY_FACILITATOR_COUNT = 3;
+    private final LruCache<Locale, DictionaryFacilitator> mDictionaryFacilitatorCache =
+            new DictionaryFacilitatorLruCache(mCachedLocales, MAX_DICTIONARY_FACILITATOR_COUNT);
+    private final ConcurrentHashMap<Locale, Keyboard> mKeyboardCache = new ConcurrentHashMap<>();
 
     // The threshold for a suggestion to be considered "recommended".
     private float mRecommendedThreshold;
     // Whether to use the contacts dictionary
     private boolean mUseContactsDictionary;
-    private final Object mUseContactsLock = new Object();
-
-    private final HashSet<WeakReference<DictionaryCollection>> mDictionaryCollectionsList =
-            new HashSet<>();
+    // TODO: make a spell checker option to block offensive words or not
+    private final SettingsValuesForSuggestion mSettingsValuesForSuggestion =
+            new SettingsValuesForSuggestion(true /* blockPotentiallyOffensive */,
+                    true /* spaceAwareGestureEnabled */,
+                    null /* additionalFeaturesSettingValues */);
+    private final Object mDictionaryLock = new Object();
 
     public static final String SINGLE_QUOTE = "\u0027";
     public static final String APOSTROPHE = "\u2019";
 
+    public AndroidSpellCheckerService() {
+        super();
+        for (int i = 0; i < MAX_NUM_OF_THREADS_READ_DICTIONARY; i++) {
+            mSessionIdPool.add(i);
+        }
+    }
+
     @Override public void onCreate() {
         super.onCreate();
         mRecommendedThreshold =
@@ -106,52 +171,21 @@ public final class AndroidSpellCheckerService extends SpellCheckerService
     @Override
     public void onSharedPreferenceChanged(final SharedPreferences prefs, final String key) {
         if (!PREF_USE_CONTACTS_KEY.equals(key)) return;
-        synchronized(mUseContactsLock) {
-            mUseContactsDictionary = prefs.getBoolean(PREF_USE_CONTACTS_KEY, true);
-            if (mUseContactsDictionary) {
-                startUsingContactsDictionaryLocked();
-            } else {
-                stopUsingContactsDictionaryLocked();
-            }
-        }
-    }
-
-    private void startUsingContactsDictionaryLocked() {
-        if (null == mContactsDictionary) {
-            // TODO: use the right locale for each session
-            mContactsDictionary =
-                    new SynchronouslyLoadedContactsBinaryDictionary(this, Locale.getDefault());
-        }
-        final Iterator<WeakReference<DictionaryCollection>> iterator =
-                mDictionaryCollectionsList.iterator();
-        while (iterator.hasNext()) {
-            final WeakReference<DictionaryCollection> dictRef = iterator.next();
-            final DictionaryCollection dict = dictRef.get();
-            if (null == dict) {
-                iterator.remove();
-            } else {
-                dict.addDictionary(mContactsDictionary);
-            }
-        }
-    }
-
-    private void stopUsingContactsDictionaryLocked() {
-        if (null == mContactsDictionary) return;
-        final Dictionary contactsDict = mContactsDictionary;
-        // TODO: revert to the concrete type when USE_BINARY_CONTACTS_DICTIONARY is no longer needed
-        mContactsDictionary = null;
-        final Iterator<WeakReference<DictionaryCollection>> iterator =
-                mDictionaryCollectionsList.iterator();
-        while (iterator.hasNext()) {
-            final WeakReference<DictionaryCollection> dictRef = iterator.next();
-            final DictionaryCollection dict = dictRef.get();
-            if (null == dict) {
-                iterator.remove();
-            } else {
-                dict.removeDictionary(contactsDict);
+            final boolean useContactsDictionary = prefs.getBoolean(PREF_USE_CONTACTS_KEY, true);
+            if (useContactsDictionary != mUseContactsDictionary) {
+                mSemaphore.acquireUninterruptibly(MAX_NUM_OF_THREADS_READ_DICTIONARY);
+                try {
+                    mUseContactsDictionary = useContactsDictionary;
+                    for (final Locale locale : mCachedLocales) {
+                        final DictionaryFacilitator dictionaryFacilitator =
+                                mDictionaryFacilitatorCache.get(locale);
+                        resetDictionariesForLocale(this /* context  */,
+                                dictionaryFacilitator, locale, mUseContactsDictionary);
+                    }
+                } finally {
+                    mSemaphore.release(MAX_NUM_OF_THREADS_READ_DICTIONARY);
+                }
             }
-        }
-        contactsDict.close();
     }
 
     @Override
@@ -203,11 +237,6 @@ public final class AndroidSpellCheckerService extends SpellCheckerService
         private final int mMaxLength;
         private int mLength = 0;
 
-        // The two following attributes are only ever filled if the requested max length
-        // is 0 (or less, which is treated the same).
-        private String mBestSuggestion = null;
-        private int mBestScore = Integer.MIN_VALUE; // As small as possible
-
         SuggestionsGatherer(final String originalText, final float recommendedThreshold,
                 final int maxLength) {
             mOriginalText = originalText;
@@ -226,20 +255,6 @@ public final class AndroidSpellCheckerService extends SpellCheckerService
 
             // Weak <- insertIndex == 0, ..., insertIndex == mLength -> Strong
             if (insertIndex == 0 && mLength >= mMaxLength) {
-                // In the future, we may want to keep track of the best suggestion score even if
-                // we are asked for 0 suggestions. In this case, we can use the following
-                // (tested) code to keep it:
-                // If the maxLength is 0 (should never be less, but if it is, it's treated as 0)
-                // then we need to keep track of the best suggestion in mBestScore and
-                // mBestSuggestion. This is so that we know whether the best suggestion makes
-                // the score cutoff, since we need to know that to return a meaningful
-                // looksLikeTypo.
-                // if (0 >= mMaxLength) {
-                //     if (score > mBestScore) {
-                //         mBestScore = score;
-                //         mBestSuggestion = new String(word, wordOffset, wordLength);
-                //     }
-                // }
                 return true;
             }
 
@@ -264,20 +279,8 @@ public final class AndroidSpellCheckerService extends SpellCheckerService
             final String[] gatheredSuggestions;
             final boolean hasRecommendedSuggestions;
             if (0 == mLength) {
-                // TODO: the comment below describes what is intended, but in the practice
-                // mBestSuggestion is only ever set to null so it doesn't work. Fix this.
-                // Either we found no suggestions, or we found some BUT the max length was 0.
-                // If we found some mBestSuggestion will not be null. If it is null, then
-                // we found none, regardless of the max length.
-                if (null == mBestSuggestion) {
-                    gatheredSuggestions = null;
-                    hasRecommendedSuggestions = false;
-                } else {
-                    gatheredSuggestions = EMPTY_STRING_ARRAY;
-                    final float normalizedScore = BinaryDictionaryUtils.calcNormalizedScore(
-                            mOriginalText, mBestSuggestion, mBestScore);
-                    hasRecommendedSuggestions = (normalizedScore > mRecommendedThreshold);
-                }
+                gatheredSuggestions = null;
+                hasRecommendedSuggestions = false;
             } else {
                 if (DBG) {
                     if (mLength != mSuggestions.size()) {
@@ -323,85 +326,114 @@ public final class AndroidSpellCheckerService extends SpellCheckerService
         }
     }
 
-    @Override
-    public boolean onUnbind(final Intent intent) {
-        closeAllDictionaries();
-        return false;
+    public boolean isValidWord(final Locale locale, final String word) {
+        mSemaphore.acquireUninterruptibly();
+        try {
+            DictionaryFacilitator dictionaryFacilitatorForLocale =
+                    getDictionaryFacilitatorForLocaleLocked(locale);
+            return dictionaryFacilitatorForLocale.isValidWord(word, false /* igroreCase */);
+        } finally {
+            mSemaphore.release();
+        }
     }
 
-    private void closeAllDictionaries() {
-        final Map<String, DictionaryPool> oldPools = mDictionaryPools;
-        mDictionaryPools = CollectionUtils.newSynchronizedTreeMap();
-        final Map<String, UserBinaryDictionary> oldUserDictionaries = mUserDictionaries;
-        mUserDictionaries = CollectionUtils.newSynchronizedTreeMap();
-        new Thread("spellchecker_close_dicts") {
-            @Override
-            public void run() {
-                // Contacts dictionary can be closed multiple times here. If the dictionary is
-                // already closed, extra closings are no-ops, so it's safe.
-                for (DictionaryPool pool : oldPools.values()) {
-                    pool.close();
-                }
-                for (Dictionary dict : oldUserDictionaries.values()) {
-                    dict.close();
-                }
-                synchronized (mUseContactsLock) {
-                    if (null != mContactsDictionary) {
-                        // The synchronously loaded contacts dictionary should have been in one
-                        // or several pools, but it is shielded against multiple closing and it's
-                        // safe to call it several times.
-                        final ContactsBinaryDictionary dictToClose = mContactsDictionary;
-                        // TODO: revert to the concrete type when USE_BINARY_CONTACTS_DICTIONARY
-                        // is no longer needed
-                        mContactsDictionary = null;
-                        dictToClose.close();
-                    }
+    public SuggestionResults getSuggestionResults(final Locale locale, final WordComposer composer,
+            final PrevWordsInfo prevWordsInfo, final ProximityInfo proximityInfo) {
+        Integer sessionId = null;
+        mSemaphore.acquireUninterruptibly();
+        try {
+            sessionId = mSessionIdPool.poll();
+            DictionaryFacilitator dictionaryFacilitatorForLocale =
+                    getDictionaryFacilitatorForLocaleLocked(locale);
+            return dictionaryFacilitatorForLocale.getSuggestionResults(composer, prevWordsInfo,
+                    proximityInfo, mSettingsValuesForSuggestion, sessionId);
+        } finally {
+            if (sessionId != null) {
+                mSessionIdPool.add(sessionId);
+            }
+            mSemaphore.release();
+        }
+    }
+
+    public boolean hasMainDictionaryForLocale(final Locale locale) {
+        mSemaphore.acquireUninterruptibly();
+        try {
+            final DictionaryFacilitator dictionaryFacilitator =
+                    getDictionaryFacilitatorForLocaleLocked(locale);
+            return dictionaryFacilitator.hasInitializedMainDictionary();
+        } finally {
+            mSemaphore.release();
+        }
+    }
+
+    private DictionaryFacilitator getDictionaryFacilitatorForLocaleLocked(final Locale locale) {
+        DictionaryFacilitator dictionaryFacilitatorForLocale =
+                mDictionaryFacilitatorCache.get(locale);
+        if (dictionaryFacilitatorForLocale == null) {
+            dictionaryFacilitatorForLocale = new DictionaryFacilitator();
+            mDictionaryFacilitatorCache.put(locale, dictionaryFacilitatorForLocale);
+            mCachedLocales.add(locale);
+            resetDictionariesForLocale(this /* context */, dictionaryFacilitatorForLocale,
+                    locale, mUseContactsDictionary);
+        }
+        return dictionaryFacilitatorForLocale;
+    }
+
+    private static void resetDictionariesForLocale(final Context context,
+            final DictionaryFacilitator dictionaryFacilitator, final Locale locale,
+            final boolean useContactsDictionary) {
+        dictionaryFacilitator.resetDictionariesWithDictNamePrefix(context, locale,
+                useContactsDictionary, false /* usePersonalizedDicts */,
+                false /* forceReloadMainDictionary */, null /* listener */,
+                DICTIONARY_NAME_PREFIX);
+        for (int i = 0; i < MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT; i++) {
+            try {
+                dictionaryFacilitator.waitForLoadingMainDictionary(
+                        WAIT_FOR_LOADING_MAIN_DICT_IN_MILLISECONDS, TimeUnit.MILLISECONDS);
+                return;
+            } catch (final InterruptedException e) {
+                Log.i(TAG, "Interrupted during waiting for loading main dictionary.", e);
+                if (i < MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT - 1) {
+                    Log.i(TAG, "Retry", e);
+                } else {
+                    Log.w(TAG, "Give up retrying. Retried "
+                            + MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT + " times.", e);
                 }
             }
-        }.start();
+        }
+    }
+
+    @Override
+    public boolean onUnbind(final Intent intent) {
+        mSemaphore.acquireUninterruptibly(MAX_NUM_OF_THREADS_READ_DICTIONARY);
+        try {
+            mDictionaryFacilitatorCache.evictAll();
+            mCachedLocales.clear();
+        } finally {
+            mSemaphore.release(MAX_NUM_OF_THREADS_READ_DICTIONARY);
+        }
+        mKeyboardCache.clear();
+        return false;
     }
 
-    public DictionaryPool getDictionaryPool(final String locale) {
-        DictionaryPool pool = mDictionaryPools.get(locale);
-        if (null == pool) {
-            final Locale localeObject = LocaleUtils.constructLocaleFromString(locale);
-            pool = new DictionaryPool(POOL_SIZE, this, localeObject);
-            mDictionaryPools.put(locale, pool);
+    public Keyboard getKeyboardForLocale(final Locale locale) {
+        Keyboard keyboard = mKeyboardCache.get(locale);
+        if (keyboard == null) {
+            keyboard = createKeyboardForLocale(locale);
+            if (keyboard != null) {
+                mKeyboardCache.put(locale, keyboard);
+            }
         }
-        return pool;
+        return keyboard;
     }
 
-    public DictAndKeyboard createDictAndKeyboard(final Locale locale) {
+    private Keyboard createKeyboardForLocale(final Locale locale) {
         final int script = ScriptUtils.getScriptFromSpellCheckerLocale(locale);
         final String keyboardLayoutName = getKeyboardLayoutNameForScript(script);
         final InputMethodSubtype subtype = AdditionalSubtypeUtils.createDummyAdditionalSubtype(
                 locale.toString(), keyboardLayoutName);
         final KeyboardLayoutSet keyboardLayoutSet = createKeyboardSetForSpellChecker(subtype);
-
-        final DictionaryCollection dictionaryCollection =
-                DictionaryFactory.createMainDictionaryFromManager(this, locale,
-                        true /* useFullEditDistance */);
-        final String localeStr = locale.toString();
-        UserBinaryDictionary userDictionary = mUserDictionaries.get(localeStr);
-        if (null == userDictionary) {
-            userDictionary = new SynchronouslyLoadedUserBinaryDictionary(this, locale, true);
-            mUserDictionaries.put(localeStr, userDictionary);
-        }
-        dictionaryCollection.addDictionary(userDictionary);
-        synchronized (mUseContactsLock) {
-            if (mUseContactsDictionary) {
-                if (null == mContactsDictionary) {
-                    // TODO: use the right locale. We can't do it right now because the
-                    // spell checker is reusing the contacts dictionary across sessions
-                    // without regard for their locale, so we need to fix that first.
-                    mContactsDictionary = new SynchronouslyLoadedContactsBinaryDictionary(this,
-                            Locale.getDefault());
-                }
-            }
-            dictionaryCollection.addDictionary(mContactsDictionary);
-            mDictionaryCollectionsList.add(new WeakReference<>(dictionaryCollection));
-        }
-        return new DictAndKeyboard(dictionaryCollection, keyboardLayoutSet);
+        return keyboardLayoutSet.getKeyboard(KeyboardId.ELEMENT_ALPHABET);
     }
 
     private KeyboardLayoutSet createKeyboardSetForSpellChecker(final InputMethodSubtype subtype) {
diff --git a/java/src/com/android/inputmethod/latin/spellcheck/AndroidWordLevelSpellCheckerSession.java b/java/src/com/android/inputmethod/latin/spellcheck/AndroidWordLevelSpellCheckerSession.java
index 08adaf844..19c1dd0a5 100644
--- a/java/src/com/android/inputmethod/latin/spellcheck/AndroidWordLevelSpellCheckerSession.java
+++ b/java/src/com/android/inputmethod/latin/spellcheck/AndroidWordLevelSpellCheckerSession.java
@@ -28,8 +28,9 @@ import android.view.textservice.SuggestionsInfo;
 import android.view.textservice.TextInfo;
 
 import com.android.inputmethod.compat.SuggestionsInfoCompatUtils;
+import com.android.inputmethod.keyboard.Keyboard;
+import com.android.inputmethod.keyboard.ProximityInfo;
 import com.android.inputmethod.latin.Constants;
-import com.android.inputmethod.latin.Dictionary;
 import com.android.inputmethod.latin.PrevWordsInfo;
 import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
 import com.android.inputmethod.latin.WordComposer;
@@ -39,17 +40,15 @@ import com.android.inputmethod.latin.utils.CoordinateUtils;
 import com.android.inputmethod.latin.utils.LocaleUtils;
 import com.android.inputmethod.latin.utils.ScriptUtils;
 import com.android.inputmethod.latin.utils.StringUtils;
+import com.android.inputmethod.latin.utils.SuggestionResults;
 
-import java.util.ArrayList;
 import java.util.Locale;
 
 public abstract class AndroidWordLevelSpellCheckerSession extends Session {
     private static final String TAG = AndroidWordLevelSpellCheckerSession.class.getSimpleName();
     private static final boolean DBG = false;
 
-    // Immutable, but need the locale which is not available in the constructor yet
-    private DictionaryPool mDictionaryPool;
-    // Likewise
+    // Immutable, but not available in the constructor.
     private Locale mLocale;
     // Cache this for performance
     private int mScript; // One of SCRIPT_LATIN or SCRIPT_CYRILLIC for now.
@@ -116,7 +115,6 @@ public abstract class AndroidWordLevelSpellCheckerSession extends Session {
     @Override
     public void onCreate() {
         final String localeString = getLocale();
-        mDictionaryPool = mService.getDictionaryPool(localeString);
         mLocale = LocaleUtils.constructLocaleFromString(localeString);
         mScript = ScriptUtils.getScriptFromSpellCheckerLocale(mLocale);
     }
@@ -191,24 +189,24 @@ public abstract class AndroidWordLevelSpellCheckerSession extends Session {
      * If the "TEXT" is fully upper case, we test the exact string "TEXT", the lower-cased
      *  version of it "text" and the capitalized version of it "Text".
      */
-    private boolean isInDictForAnyCapitalization(final Dictionary dict, final String text,
-            final int capitalizeType) {
+    private boolean isInDictForAnyCapitalization(final String text, final int capitalizeType) {
         // If the word is in there as is, then it's in the dictionary. If not, we'll test lower
         // case versions, but only if the word is not already all-lower case or mixed case.
-        if (dict.isValidWord(text)) return true;
+        if (mService.isValidWord(mLocale, text)) return true;
         if (StringUtils.CAPITALIZE_NONE == capitalizeType) return false;
 
         // If we come here, we have a capitalized word (either First- or All-).
         // Downcase the word and look it up again. If the word is only capitalized, we
         // tested all possibilities, so if it's still negative we can return false.
         final String lowerCaseText = text.toLowerCase(mLocale);
-        if (dict.isValidWord(lowerCaseText)) return true;
+        if (mService.isValidWord(mLocale, lowerCaseText)) return true;
         if (StringUtils.CAPITALIZE_FIRST == capitalizeType) return false;
 
         // If the lower case version is not in the dictionary, it's still possible
         // that we have an all-caps version of a word that needs to be capitalized
         // according to the dictionary. E.g. "GERMANS" only exists in the dictionary as "Germans".
-        return dict.isValidWord(StringUtils.capitalizeFirstAndDowncaseRest(lowerCaseText, mLocale));
+        return mService.isValidWord(mLocale,
+                StringUtils.capitalizeFirstAndDowncaseRest(lowerCaseText, mLocale));
     }
 
     // Note : this must be reentrant
@@ -236,46 +234,28 @@ public abstract class AndroidWordLevelSpellCheckerSession extends Session {
                 return new SuggestionsInfo(
                         cachedSuggestionsParams.mFlags, cachedSuggestionsParams.mSuggestions);
             }
-
             final int checkability = getCheckabilityInScript(inText, mScript);
             if (CHECKABILITY_CHECKABLE != checkability) {
-                DictAndKeyboard dictInfo = null;
-                try {
-                    dictInfo = mDictionaryPool.pollWithDefaultTimeout();
-                    if (!DictionaryPool.isAValidDictionary(dictInfo)) {
-                        return AndroidSpellCheckerService.getNotInDictEmptySuggestions(
-                                false /* reportAsTypo */);
-                    }
-                    if (CHECKABILITY_CONTAINS_PERIOD == checkability) {
-                        final String[] splitText = inText.split(Constants.REGEXP_PERIOD);
-                        boolean allWordsAreValid = true;
-                        for (final String word : splitText) {
-                            if (!dictInfo.mDictionary.isValidWord(word)) {
-                                allWordsAreValid = false;
-                                break;
-                            }
-                        }
-                        if (allWordsAreValid) {
-                            return new SuggestionsInfo(SuggestionsInfo.RESULT_ATTR_LOOKS_LIKE_TYPO
-                                    | SuggestionsInfo.RESULT_ATTR_HAS_RECOMMENDED_SUGGESTIONS,
-                                    new String[] {
-                                            TextUtils.join(Constants.STRING_SPACE, splitText),
-                                            TextUtils.join(Constants.STRING_PERIOD_AND_SPACE,
-                                                    splitText) });
+                if (CHECKABILITY_CONTAINS_PERIOD == checkability) {
+                    final String[] splitText = inText.split(Constants.REGEXP_PERIOD);
+                    boolean allWordsAreValid = true;
+                    for (final String word : splitText) {
+                        if (!mService.isValidWord(mLocale, word)) {
+                            allWordsAreValid = false;
+                            break;
                         }
                     }
-                    return dictInfo.mDictionary.isValidWord(inText)
-                            ? AndroidSpellCheckerService.getInDictEmptySuggestions()
-                            : AndroidSpellCheckerService.getNotInDictEmptySuggestions(
-                                    CHECKABILITY_CONTAINS_PERIOD == checkability
-                                    /* reportAsTypo */);
-                } finally {
-                    if (null != dictInfo) {
-                        if (!mDictionaryPool.offer(dictInfo)) {
-                            Log.e(TAG, "Can't re-insert a dictionary into its pool");
-                        }
+                    if (allWordsAreValid) {
+                        return new SuggestionsInfo(SuggestionsInfo.RESULT_ATTR_LOOKS_LIKE_TYPO
+                                | SuggestionsInfo.RESULT_ATTR_HAS_RECOMMENDED_SUGGESTIONS,
+                                new String[] {
+                                        TextUtils.join(Constants.STRING_SPACE, splitText) });
                     }
                 }
+                return mService.isValidWord(mLocale, inText) ?
+                        AndroidSpellCheckerService.getInDictEmptySuggestions() :
+                        AndroidSpellCheckerService.getNotInDictEmptySuggestions(
+                                CHECKABILITY_CONTAINS_PERIOD == checkability /* reportAsTypo */);
             }
             final String text = inText.replaceAll(
                     AndroidSpellCheckerService.APOSTROPHE, AndroidSpellCheckerService.SINGLE_QUOTE);
@@ -289,48 +269,34 @@ public abstract class AndroidWordLevelSpellCheckerSession extends Session {
 
             final int capitalizeType = StringUtils.getCapitalizationType(text);
             boolean isInDict = true;
-            DictAndKeyboard dictInfo = null;
-            try {
-                dictInfo = mDictionaryPool.pollWithDefaultTimeout();
-                if (!DictionaryPool.isAValidDictionary(dictInfo)) {
-                    return AndroidSpellCheckerService.getNotInDictEmptySuggestions(
-                            false /* reportAsTypo */);
-                }
-                final WordComposer composer = new WordComposer();
-                final int[] codePoints = StringUtils.toCodePointArray(text);
-                final int[] coordinates;
-                if (null == dictInfo.mKeyboard) {
-                    coordinates = CoordinateUtils.newCoordinateArray(codePoints.length,
-                            Constants.NOT_A_COORDINATE, Constants.NOT_A_COORDINATE);
-                } else {
-                    coordinates = dictInfo.mKeyboard.getCoordinates(codePoints);
-                }
-                composer.setComposingWord(codePoints, coordinates);
-                // TODO: make a spell checker option to block offensive words or not
-                final ArrayList<SuggestedWordInfo> suggestions =
-                        dictInfo.mDictionary.getSuggestions(composer, prevWordsInfo,
-                                dictInfo.getProximityInfo(),
-                                new SettingsValuesForSuggestion(
-                                        true /* blockPotentiallyOffensive */,
-                                        true /* spaceAwareGestureEnabled */,
-                                        null /* additionalFeaturesSettingValues */),
-                                0 /* sessionId */,
-                                null /* inOutLanguageWeight */);
-                if (suggestions != null) {
-                    for (final SuggestedWordInfo suggestion : suggestions) {
-                        final String suggestionStr = suggestion.mWord;
-                        suggestionsGatherer.addWord(suggestionStr.toCharArray(), null, 0,
-                                suggestionStr.length(), suggestion.mScore);
-                    }
-                }
-                isInDict = isInDictForAnyCapitalization(dictInfo.mDictionary, text, capitalizeType);
-            } finally {
-                if (null != dictInfo) {
-                    if (!mDictionaryPool.offer(dictInfo)) {
-                        Log.e(TAG, "Can't re-insert a dictionary into its pool");
-                    }
+            if (!mService.hasMainDictionaryForLocale(mLocale)) {
+                return AndroidSpellCheckerService.getNotInDictEmptySuggestions(
+                        false /* reportAsTypo */);
+            }
+            final Keyboard keyboard = mService.getKeyboardForLocale(mLocale);
+            final WordComposer composer = new WordComposer();
+            final int[] codePoints = StringUtils.toCodePointArray(text);
+            final int[] coordinates;
+            final ProximityInfo proximityInfo;
+            if (null == keyboard) {
+                coordinates = CoordinateUtils.newCoordinateArray(codePoints.length,
+                        Constants.NOT_A_COORDINATE, Constants.NOT_A_COORDINATE);
+                proximityInfo = null;
+            } else {
+                coordinates = keyboard.getCoordinates(codePoints);
+                proximityInfo = keyboard.getProximityInfo();
+            }
+            composer.setComposingWord(codePoints, coordinates);
+            final SuggestionResults suggestionResults = mService.getSuggestionResults(
+                    mLocale, composer, prevWordsInfo, proximityInfo);
+            if (suggestionResults != null) {
+                for (final SuggestedWordInfo suggestion : suggestionResults) {
+                    final String suggestionStr = suggestion.mWord;
+                    suggestionsGatherer.addWord(suggestionStr.toCharArray(), null, 0,
+                            suggestionStr.length(), suggestion.mScore);
                 }
             }
+            isInDict = isInDictForAnyCapitalization(text, capitalizeType);
 
             final SuggestionsGatherer.Result result = suggestionsGatherer.getResults(
                     capitalizeType, mLocale);
diff --git a/java/src/com/android/inputmethod/latin/spellcheck/DictAndKeyboard.java b/java/src/com/android/inputmethod/latin/spellcheck/DictAndKeyboard.java
deleted file mode 100644
index b33739fc1..000000000
--- a/java/src/com/android/inputmethod/latin/spellcheck/DictAndKeyboard.java
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
- * Copyright (C) 2011 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.latin.spellcheck;
-
-import com.android.inputmethod.keyboard.Keyboard;
-import com.android.inputmethod.keyboard.KeyboardId;
-import com.android.inputmethod.keyboard.KeyboardLayoutSet;
-import com.android.inputmethod.keyboard.ProximityInfo;
-import com.android.inputmethod.latin.Dictionary;
-
-/**
- * A container for a Dictionary and a Keyboard.
- */
-public final class DictAndKeyboard {
-    public final Dictionary mDictionary;
-    public final Keyboard mKeyboard;
-
-    public DictAndKeyboard(
-            final Dictionary dictionary, final KeyboardLayoutSet keyboardLayoutSet) {
-        mDictionary = dictionary;
-        if (keyboardLayoutSet == null) {
-            mKeyboard = null;
-            return;
-        }
-        mKeyboard = keyboardLayoutSet.getKeyboard(KeyboardId.ELEMENT_ALPHABET);
-    }
-
-    public ProximityInfo getProximityInfo() {
-        return mKeyboard == null ? null : mKeyboard.getProximityInfo();
-    }
-}
diff --git a/java/src/com/android/inputmethod/latin/spellcheck/DictionaryPool.java b/java/src/com/android/inputmethod/latin/spellcheck/DictionaryPool.java
deleted file mode 100644
index eb85d4969..000000000
--- a/java/src/com/android/inputmethod/latin/spellcheck/DictionaryPool.java
+++ /dev/null
@@ -1,137 +0,0 @@
-/*
- * Copyright (C) 2011 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.latin.spellcheck;
-
-import android.util.Log;
-
-import com.android.inputmethod.keyboard.ProximityInfo;
-import com.android.inputmethod.latin.Dictionary;
-import com.android.inputmethod.latin.PrevWordsInfo;
-import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
-import com.android.inputmethod.latin.settings.SettingsValuesForSuggestion;
-import com.android.inputmethod.latin.WordComposer;
-
-import java.util.ArrayList;
-import java.util.Locale;
-import java.util.concurrent.LinkedBlockingQueue;
-import java.util.concurrent.TimeUnit;
-
-/**
- * A blocking queue that creates dictionaries up to a certain limit as necessary.
- * As a deadlock-detecting device, if waiting for more than TIMEOUT = 3 seconds, we
- * will clear the queue and generate its contents again. This is transparent for
- * the client code, but may help with sloppy clients.
- */
-@SuppressWarnings("serial")
-public final class DictionaryPool extends LinkedBlockingQueue<DictAndKeyboard> {
-    private final static String TAG = DictionaryPool.class.getSimpleName();
-    // How many seconds we wait for a dictionary to become available. Past this delay, we give up in
-    // fear some bug caused a deadlock, and reset the whole pool.
-    private final static int TIMEOUT = 3;
-    private final AndroidSpellCheckerService mService;
-    private final int mMaxSize;
-    private final Locale mLocale;
-    private int mSize;
-    private volatile boolean mClosed;
-    final static ArrayList<SuggestedWordInfo> noSuggestions = new ArrayList<>();
-    private final static DictAndKeyboard dummyDict = new DictAndKeyboard(
-            new Dictionary(Dictionary.TYPE_MAIN) {
-                // TODO: this dummy dictionary should be a singleton in the Dictionary class.
-                @Override
-                public ArrayList<SuggestedWordInfo> getSuggestions(final WordComposer composer,
-                        final PrevWordsInfo prevWordsInfo, final ProximityInfo proximityInfo,
-                        final SettingsValuesForSuggestion settingsValuesForSuggestion,
-                        final int sessionId, final float[] inOutLanguageWeight) {
-                    return noSuggestions;
-                }
-                @Override
-                public boolean isInDictionary(final String word) {
-                    // This is never called. However if for some strange reason it ever gets
-                    // called, returning true is less destructive (it will not underline the
-                    // word in red).
-                    return true;
-                }
-            }, null);
-
-    static public boolean isAValidDictionary(final DictAndKeyboard dictInfo) {
-        return null != dictInfo && dummyDict != dictInfo;
-    }
-
-    public DictionaryPool(final int maxSize, final AndroidSpellCheckerService service,
-            final Locale locale) {
-        super();
-        mMaxSize = maxSize;
-        mService = service;
-        mLocale = locale;
-        mSize = 0;
-        mClosed = false;
-    }
-
-    @Override
-    public DictAndKeyboard poll(final long timeout, final TimeUnit unit)
-            throws InterruptedException {
-        final DictAndKeyboard dict = poll();
-        if (null != dict) return dict;
-        synchronized(this) {
-            if (mSize >= mMaxSize) {
-                // Our pool is already full. Wait until some dictionary is ready, or TIMEOUT
-                // expires to avoid a deadlock.
-                final DictAndKeyboard result = super.poll(timeout, unit);
-                if (null == result) {
-                    Log.e(TAG, "Deadlock detected ! Resetting dictionary pool");
-                    clear();
-                    mSize = 1;
-                    return mService.createDictAndKeyboard(mLocale);
-                } else {
-                    return result;
-                }
-            } else {
-                ++mSize;
-                return mService.createDictAndKeyboard(mLocale);
-            }
-        }
-    }
-
-    // Convenience method
-    public DictAndKeyboard pollWithDefaultTimeout() {
-        try {
-            return poll(TIMEOUT, TimeUnit.SECONDS);
-        } catch (InterruptedException e) {
-            return null;
-        }
-    }
-
-    public void close() {
-        synchronized(this) {
-            mClosed = true;
-            for (DictAndKeyboard dict : this) {
-                dict.mDictionary.close();
-            }
-            clear();
-        }
-    }
-
-    @Override
-    public boolean offer(final DictAndKeyboard dict) {
-        if (mClosed) {
-            dict.mDictionary.close();
-            return super.offer(dummyDict);
-        } else {
-            return super.offer(dict);
-        }
-    }
-}
diff --git a/java/src/com/android/inputmethod/latin/spellcheck/SynchronouslyLoadedContactsBinaryDictionary.java b/java/src/com/android/inputmethod/latin/spellcheck/SynchronouslyLoadedContactsBinaryDictionary.java
deleted file mode 100644
index 688b184cb..000000000
--- a/java/src/com/android/inputmethod/latin/spellcheck/SynchronouslyLoadedContactsBinaryDictionary.java
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Copyright (C) 2012 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.latin.spellcheck;
-
-import android.content.Context;
-
-import com.android.inputmethod.keyboard.ProximityInfo;
-import com.android.inputmethod.latin.ContactsBinaryDictionary;
-import com.android.inputmethod.latin.PrevWordsInfo;
-import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
-import com.android.inputmethod.latin.settings.SettingsValuesForSuggestion;
-import com.android.inputmethod.latin.WordComposer;
-
-import java.util.ArrayList;
-import java.util.Locale;
-
-public final class SynchronouslyLoadedContactsBinaryDictionary extends ContactsBinaryDictionary {
-    private static final String NAME = "spellcheck_contacts";
-    private final Object mLock = new Object();
-
-    public SynchronouslyLoadedContactsBinaryDictionary(final Context context, final Locale locale) {
-        super(context, locale, null /* dictFile */, NAME);
-    }
-
-    @Override
-    public ArrayList<SuggestedWordInfo> getSuggestions(final WordComposer codes,
-            final PrevWordsInfo prevWordsInfo, final ProximityInfo proximityInfo,
-            final SettingsValuesForSuggestion settingsValuesForSuggestion,
-            final int sessionId, final float[] inOutLanguageWeight) {
-        synchronized (mLock) {
-            return super.getSuggestions(codes, prevWordsInfo, proximityInfo,
-                    settingsValuesForSuggestion, sessionId, inOutLanguageWeight);
-        }
-    }
-
-    @Override
-    public boolean isInDictionary(final String word) {
-        synchronized (mLock) {
-            return super.isInDictionary(word);
-        }
-    }
-}
diff --git a/java/src/com/android/inputmethod/latin/spellcheck/SynchronouslyLoadedUserBinaryDictionary.java b/java/src/com/android/inputmethod/latin/spellcheck/SynchronouslyLoadedUserBinaryDictionary.java
deleted file mode 100644
index ff71f59f8..000000000
--- a/java/src/com/android/inputmethod/latin/spellcheck/SynchronouslyLoadedUserBinaryDictionary.java
+++ /dev/null
@@ -1,61 +0,0 @@
-/*
- * Copyright (C) 2012 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.latin.spellcheck;
-
-import android.content.Context;
-
-import com.android.inputmethod.keyboard.ProximityInfo;
-import com.android.inputmethod.latin.PrevWordsInfo;
-import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
-import com.android.inputmethod.latin.settings.SettingsValuesForSuggestion;
-import com.android.inputmethod.latin.UserBinaryDictionary;
-import com.android.inputmethod.latin.WordComposer;
-
-import java.util.ArrayList;
-import java.util.Locale;
-
-public final class SynchronouslyLoadedUserBinaryDictionary extends UserBinaryDictionary {
-    private static final String NAME = "spellcheck_user";
-    private final Object mLock = new Object();
-
-    public SynchronouslyLoadedUserBinaryDictionary(final Context context, final Locale locale) {
-        this(context, locale, false /* alsoUseMoreRestrictiveLocales */);
-    }
-
-    public SynchronouslyLoadedUserBinaryDictionary(final Context context, final Locale locale,
-            final boolean alsoUseMoreRestrictiveLocales) {
-        super(context, locale, alsoUseMoreRestrictiveLocales, null /* dictFile */, NAME);
-    }
-
-    @Override
-    public ArrayList<SuggestedWordInfo> getSuggestions(final WordComposer codes,
-            final PrevWordsInfo prevWordsInfo, final ProximityInfo proximityInfo,
-            final SettingsValuesForSuggestion settingsValuesForSuggestion,
-            final int sessionId, final float[] inOutLanguageWeight) {
-        synchronized (mLock) {
-            return super.getSuggestions(codes, prevWordsInfo, proximityInfo,
-                    settingsValuesForSuggestion, sessionId, inOutLanguageWeight);
-        }
-    }
-
-    @Override
-    public boolean isInDictionary(final String word) {
-        synchronized (mLock) {
-            return super.isInDictionary(word);
-        }
-    }
-}