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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.inputmethod.latin;
     18 
     19 import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
     20 
     21 import android.text.TextUtils;
     22 import android.util.Log;
     23 
     24 import java.util.ArrayList;
     25 import java.util.concurrent.ConcurrentHashMap;
     26 
     27 public class AutoCorrection {
     28     private static final boolean DBG = LatinImeLogger.sDBG;
     29     private static final String TAG = AutoCorrection.class.getSimpleName();
     30 
     31     private AutoCorrection() {
     32         // Purely static class: can't instantiate.
     33     }
     34 
     35     public static CharSequence computeAutoCorrectionWord(
     36             final ConcurrentHashMap<String, Dictionary> dictionaries,
     37             final WordComposer wordComposer, final ArrayList<SuggestedWordInfo> suggestions,
     38             final CharSequence consideredWord, final float autoCorrectionThreshold,
     39             final CharSequence whitelistedWord) {
     40         if (hasAutoCorrectionForWhitelistedWord(whitelistedWord)) {
     41             return whitelistedWord;
     42         } else if (hasAutoCorrectionForConsideredWord(
     43                 dictionaries, wordComposer, suggestions, consideredWord)) {
     44             return consideredWord;
     45         } else if (hasAutoCorrectionForBinaryDictionary(wordComposer, suggestions,
     46                 consideredWord, autoCorrectionThreshold)) {
     47             return suggestions.get(0).mWord;
     48         }
     49         return null;
     50     }
     51 
     52     public static boolean isValidWord(final ConcurrentHashMap<String, Dictionary> dictionaries,
     53             CharSequence word, boolean ignoreCase) {
     54         if (TextUtils.isEmpty(word)) {
     55             return false;
     56         }
     57         final CharSequence lowerCasedWord = word.toString().toLowerCase();
     58         for (final String key : dictionaries.keySet()) {
     59             if (key.equals(Suggest.DICT_KEY_WHITELIST)) continue;
     60             final Dictionary dictionary = dictionaries.get(key);
     61             // It's unclear how realistically 'dictionary' can be null, but the monkey is somehow
     62             // managing to get null in here. Presumably the language is changing to a language with
     63             // no main dictionary and the monkey manages to type a whole word before the thread
     64             // that reads the dictionary is started or something?
     65             // Ideally the passed map would come out of a {@link java.util.concurrent.Future} and
     66             // would be immutable once it's finished initializing, but concretely a null test is
     67             // probably good enough for the time being.
     68             if (null == dictionary) continue;
     69             if (dictionary.isValidWord(word)
     70                     || (ignoreCase && dictionary.isValidWord(lowerCasedWord))) {
     71                 return true;
     72             }
     73         }
     74         return false;
     75     }
     76 
     77     public static int getMaxFrequency(final ConcurrentHashMap<String, Dictionary> dictionaries,
     78             CharSequence word) {
     79         if (TextUtils.isEmpty(word)) {
     80             return Dictionary.NOT_A_PROBABILITY;
     81         }
     82         int maxFreq = -1;
     83         for (final String key : dictionaries.keySet()) {
     84             if (key.equals(Suggest.DICT_KEY_WHITELIST)) continue;
     85             final Dictionary dictionary = dictionaries.get(key);
     86             if (null == dictionary) continue;
     87             final int tempFreq = dictionary.getFrequency(word);
     88             if (tempFreq >= maxFreq) {
     89                 maxFreq = tempFreq;
     90             }
     91         }
     92         return maxFreq;
     93     }
     94 
     95     public static boolean allowsToBeAutoCorrected(
     96             final ConcurrentHashMap<String, Dictionary> dictionaries,
     97             final CharSequence word, final boolean ignoreCase) {
     98         final WhitelistDictionary whitelistDictionary =
     99                 (WhitelistDictionary)dictionaries.get(Suggest.DICT_KEY_WHITELIST);
    100         // If "word" is in the whitelist dictionary, it should not be auto corrected.
    101         if (whitelistDictionary != null
    102                 && whitelistDictionary.shouldForciblyAutoCorrectFrom(word)) {
    103             return true;
    104         }
    105         return !isValidWord(dictionaries, word, ignoreCase);
    106     }
    107 
    108     private static boolean hasAutoCorrectionForWhitelistedWord(CharSequence whiteListedWord) {
    109         return whiteListedWord != null;
    110     }
    111 
    112     private static boolean hasAutoCorrectionForConsideredWord(
    113             final ConcurrentHashMap<String, Dictionary> dictionaries,
    114             final WordComposer wordComposer, final ArrayList<SuggestedWordInfo> suggestions,
    115             final CharSequence consideredWord) {
    116         if (TextUtils.isEmpty(consideredWord)) return false;
    117         return wordComposer.size() > 1 && suggestions.size() > 0
    118                 && !allowsToBeAutoCorrected(dictionaries, consideredWord, false);
    119     }
    120 
    121     private static boolean hasAutoCorrectionForBinaryDictionary(WordComposer wordComposer,
    122             ArrayList<SuggestedWordInfo> suggestions,
    123             CharSequence consideredWord, float autoCorrectionThreshold) {
    124         if (wordComposer.size() > 1 && suggestions.size() > 0) {
    125             final SuggestedWordInfo autoCorrectionSuggestion = suggestions.get(0);
    126             //final int autoCorrectionSuggestionScore = sortedScores[0];
    127             final int autoCorrectionSuggestionScore = autoCorrectionSuggestion.mScore;
    128             // TODO: when the normalized score of the first suggestion is nearly equals to
    129             //       the normalized score of the second suggestion, behave less aggressive.
    130             final float normalizedScore = BinaryDictionary.calcNormalizedScore(
    131                     consideredWord.toString(), autoCorrectionSuggestion.mWord.toString(),
    132                     autoCorrectionSuggestionScore);
    133             if (DBG) {
    134                 Log.d(TAG, "Normalized " + consideredWord + "," + autoCorrectionSuggestion + ","
    135                         + autoCorrectionSuggestionScore + ", " + normalizedScore
    136                         + "(" + autoCorrectionThreshold + ")");
    137             }
    138             if (normalizedScore >= autoCorrectionThreshold) {
    139                 if (DBG) {
    140                     Log.d(TAG, "Auto corrected by S-threshold.");
    141                 }
    142                 return true;
    143             }
    144         }
    145         return false;
    146     }
    147 
    148 }
    149