UserHistoryDictionary.java revision 86f36003fd4397143bd37938dda029e5707634af 
1/*
2 * Copyright (C) 2013 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
17package com.android.inputmethod.latin.personalization;
18
19import android.content.Context;
20import android.text.TextUtils;
21
22import com.android.inputmethod.annotations.UsedForTesting;
23import com.android.inputmethod.latin.Constants;
24import com.android.inputmethod.latin.Dictionary;
25import com.android.inputmethod.latin.ExpandableBinaryDictionary;
26import com.android.inputmethod.latin.PrevWordsInfo;
27import com.android.inputmethod.latin.utils.DistracterFilter;
28
29import java.io.File;
30import java.util.Locale;
31
32/**
33 * Locally gathers stats about the words user types and various other signals like auto-correction
34 * cancellation or manual picks. This allows the keyboard to adapt to the typist over time.
35 */
36public class UserHistoryDictionary extends DecayingExpandableBinaryDictionaryBase {
37    /* package */ static final String NAME = UserHistoryDictionary.class.getSimpleName();
38
39    // TODO: Make this constructor private
40    /* package */ UserHistoryDictionary(final Context context, final Locale locale) {
41        super(context, getDictName(NAME, locale, null /* dictFile */), locale,
42                Dictionary.TYPE_USER_HISTORY, null /* dictFile */);
43    }
44
45    @UsedForTesting
46    public static UserHistoryDictionary getDictionary(final Context context, final Locale locale,
47            final File dictFile, final String dictNamePrefix) {
48        return PersonalizationHelper.getUserHistoryDictionary(context, locale);
49    }
50
51    /**
52     * Add a word to the user history dictionary.
53     *
54     * @param userHistoryDictionary the user history dictionary
55     * @param prevWordsInfo the information of previous words
56     * @param word the word the user inputted
57     * @param isValid whether the word is valid or not
58     * @param timestamp the timestamp when the word has been inputted
59     * @param distracterFilter the filter to check whether the word is a distracter
60     */
61    public static void addToDictionary(final ExpandableBinaryDictionary userHistoryDictionary,
62            final PrevWordsInfo prevWordsInfo, final String word, final boolean isValid,
63            final int timestamp, final DistracterFilter distracterFilter) {
64        final CharSequence prevWord = prevWordsInfo.mPrevWordsInfo[0].mWord;
65        if (word.length() >= Constants.DICTIONARY_MAX_WORD_LENGTH ||
66                (prevWord != null && prevWord.length() >= Constants.DICTIONARY_MAX_WORD_LENGTH)) {
67            return;
68        }
69        final int frequency = isValid ?
70                FREQUENCY_FOR_WORDS_IN_DICTS : FREQUENCY_FOR_WORDS_NOT_IN_DICTS;
71        userHistoryDictionary.addUnigramEntryWithCheckingDistracter(word, frequency,
72                null /* shortcutTarget */, 0 /* shortcutFreq */, false /* isNotAWord */,
73                false /* isBlacklisted */, timestamp, distracterFilter);
74        // Do not insert a word as a bigram of itself
75        if (TextUtils.equals(word, prevWord)) {
76            return;
77        }
78        if (null != prevWord) {
79            if (prevWordsInfo.mPrevWordsInfo[0].mIsBeginningOfSentence) {
80                // Beginning-of-Sentence n-gram entry is treated as a n-gram entry of invalid word.
81                userHistoryDictionary.addNgramEntry(prevWordsInfo, word,
82                        FREQUENCY_FOR_WORDS_NOT_IN_DICTS, timestamp);
83            } else {
84                userHistoryDictionary.addNgramEntry(prevWordsInfo, word, frequency, timestamp);
85            }
86        }
87    }
88}
89