LatinIME/java/src/com/android/inputmethod/latin/Suggest.java

596 lines
27 KiB
Java

/*
* Copyright (C) 2008 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;
import android.content.Context;
import android.text.TextUtils;
import android.util.Log;
import com.android.inputmethod.keyboard.Keyboard;
import com.android.inputmethod.keyboard.ProximityInfo;
import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Locale;
/**
* This class loads a dictionary and provides a list of suggestions for a given sequence of
* characters. This includes corrections and completions.
*/
public class Suggest implements Dictionary.WordCallback {
public static final String TAG = Suggest.class.getSimpleName();
public static final int APPROX_MAX_WORD_LENGTH = 32;
public static final int CORRECTION_NONE = 0;
public static final int CORRECTION_FULL = 1;
public static final int CORRECTION_FULL_BIGRAM = 2;
/**
* Words that appear in both bigram and unigram data gets multiplier ranging from
* BIGRAM_MULTIPLIER_MIN to BIGRAM_MULTIPLIER_MAX depending on the score from
* bigram data.
*/
public static final double BIGRAM_MULTIPLIER_MIN = 1.2;
public static final double BIGRAM_MULTIPLIER_MAX = 1.5;
/**
* Maximum possible bigram frequency. Will depend on how many bits are being used in data
* structure. Maximum bigram frequency will get the BIGRAM_MULTIPLIER_MAX as the multiplier.
*/
public static final int MAXIMUM_BIGRAM_FREQUENCY = 127;
// It seems the following values are only used for logging.
public static final int DIC_USER_TYPED = 0;
public static final int DIC_MAIN = 1;
public static final int DIC_USER = 2;
public static final int DIC_USER_HISTORY = 3;
public static final int DIC_CONTACTS = 4;
public static final int DIC_WHITELIST = 6;
// If you add a type of dictionary, increment DIC_TYPE_LAST_ID
// TODO: this value seems unused. Remove it?
public static final int DIC_TYPE_LAST_ID = 6;
public static final String DICT_KEY_MAIN = "main";
public static final String DICT_KEY_CONTACTS = "contacts";
// User dictionary, the system-managed one.
public static final String DICT_KEY_USER = "user";
// User history dictionary for the unigram map, internal to LatinIME
public static final String DICT_KEY_USER_HISTORY_UNIGRAM = "history_unigram";
// User history dictionary for the bigram map, internal to LatinIME
public static final String DICT_KEY_USER_HISTORY_BIGRAM = "history_bigram";
public static final String DICT_KEY_WHITELIST ="whitelist";
private static final boolean DBG = LatinImeLogger.sDBG;
private Dictionary mMainDict;
private ContactsDictionary mContactsDict;
private WhitelistDictionary mWhiteListDictionary;
private final HashMap<String, Dictionary> mUnigramDictionaries =
new HashMap<String, Dictionary>();
private final HashMap<String, Dictionary> mBigramDictionaries =
new HashMap<String, Dictionary>();
private int mPrefMaxSuggestions = 18;
private static final int PREF_MAX_BIGRAMS = 60;
private double mAutoCorrectionThreshold;
private ArrayList<SuggestedWordInfo> mSuggestions = new ArrayList<SuggestedWordInfo>();
private ArrayList<SuggestedWordInfo> mBigramSuggestions = new ArrayList<SuggestedWordInfo>();
private CharSequence mConsideredWord;
// TODO: Remove these member variables by passing more context to addWord() callback method
private boolean mIsFirstCharCapitalized;
private boolean mIsAllUpperCase;
private int mTrailingSingleQuotesCount;
private static final int MINIMUM_SAFETY_NET_CHAR_LENGTH = 4;
public Suggest(final Context context, final int dictionaryResId, final Locale locale) {
initAsynchronously(context, dictionaryResId, locale);
}
/* package for test */ Suggest(final Context context, final File dictionary,
final long startOffset, final long length, final Flag[] flagArray,
final Locale locale) {
initSynchronously(context, DictionaryFactory.createDictionaryForTest(context, dictionary,
startOffset, length, flagArray), locale);
}
private void initWhitelistAndAutocorrectAndPool(final Context context, final Locale locale) {
mWhiteListDictionary = new WhitelistDictionary(context, locale);
addOrReplaceDictionary(mUnigramDictionaries, DICT_KEY_WHITELIST, mWhiteListDictionary);
}
private void initAsynchronously(final Context context, final int dictionaryResId,
final Locale locale) {
resetMainDict(context, dictionaryResId, locale);
// TODO: read the whitelist and init the pool asynchronously too.
// initPool should be done asynchronously now that the pool is thread-safe.
initWhitelistAndAutocorrectAndPool(context, locale);
}
private void initSynchronously(final Context context, final Dictionary mainDict,
final Locale locale) {
mMainDict = mainDict;
addOrReplaceDictionary(mUnigramDictionaries, DICT_KEY_MAIN, mainDict);
addOrReplaceDictionary(mBigramDictionaries, DICT_KEY_MAIN, mainDict);
initWhitelistAndAutocorrectAndPool(context, locale);
}
private static void addOrReplaceDictionary(HashMap<String, Dictionary> dictionaries, String key,
Dictionary dict) {
final Dictionary oldDict = (dict == null)
? dictionaries.remove(key)
: dictionaries.put(key, dict);
if (oldDict != null && dict != oldDict) {
oldDict.close();
}
}
public void resetMainDict(final Context context, final int dictionaryResId,
final Locale locale) {
mMainDict = null;
new Thread("InitializeBinaryDictionary") {
@Override
public void run() {
final Dictionary newMainDict = DictionaryFactory.createDictionaryFromManager(
context, locale, dictionaryResId);
mMainDict = newMainDict;
addOrReplaceDictionary(mUnigramDictionaries, DICT_KEY_MAIN, newMainDict);
addOrReplaceDictionary(mBigramDictionaries, DICT_KEY_MAIN, newMainDict);
}
}.start();
}
// The main dictionary could have been loaded asynchronously. Don't cache the return value
// of this method.
public boolean hasMainDictionary() {
return mMainDict != null;
}
public ContactsDictionary getContactsDictionary() {
return mContactsDict;
}
public HashMap<String, Dictionary> getUnigramDictionaries() {
return mUnigramDictionaries;
}
public static int getApproxMaxWordLength() {
return APPROX_MAX_WORD_LENGTH;
}
/**
* Sets an optional user dictionary resource to be loaded. The user dictionary is consulted
* before the main dictionary, if set. This refers to the system-managed user dictionary.
*/
public void setUserDictionary(Dictionary userDictionary) {
addOrReplaceDictionary(mUnigramDictionaries, DICT_KEY_USER, userDictionary);
}
/**
* Sets an optional contacts dictionary resource to be loaded. It is also possible to remove
* the contacts dictionary by passing null to this method. In this case no contacts dictionary
* won't be used.
*/
public void setContactsDictionary(ContactsDictionary contactsDictionary) {
mContactsDict = contactsDictionary;
addOrReplaceDictionary(mUnigramDictionaries, DICT_KEY_CONTACTS, contactsDictionary);
addOrReplaceDictionary(mBigramDictionaries, DICT_KEY_CONTACTS, contactsDictionary);
}
public void setUserHistoryDictionary(Dictionary userHistoryDictionary) {
addOrReplaceDictionary(mUnigramDictionaries, DICT_KEY_USER_HISTORY_UNIGRAM,
userHistoryDictionary);
addOrReplaceDictionary(mBigramDictionaries, DICT_KEY_USER_HISTORY_BIGRAM,
userHistoryDictionary);
}
public void setAutoCorrectionThreshold(double threshold) {
mAutoCorrectionThreshold = threshold;
}
private static CharSequence capitalizeWord(final boolean all, final boolean first,
final CharSequence word) {
if (TextUtils.isEmpty(word) || !(all || first)) return word;
final int wordLength = word.length();
final StringBuilder sb = new StringBuilder(getApproxMaxWordLength());
// TODO: Must pay attention to locale when changing case.
if (all) {
sb.append(word.toString().toUpperCase());
} else if (first) {
sb.append(Character.toUpperCase(word.charAt(0)));
if (wordLength > 1) {
sb.append(word.subSequence(1, wordLength));
}
}
return sb;
}
protected void addBigramToSuggestions(SuggestedWordInfo bigram) {
mSuggestions.add(bigram);
}
private static final WordComposer sEmptyWordComposer = new WordComposer();
public SuggestedWords getBigramPredictions(CharSequence prevWordForBigram) {
LatinImeLogger.onStartSuggestion(prevWordForBigram);
mIsFirstCharCapitalized = false;
mIsAllUpperCase = false;
mTrailingSingleQuotesCount = 0;
mSuggestions = new ArrayList<SuggestedWordInfo>(mPrefMaxSuggestions);
// Treating USER_TYPED as UNIGRAM suggestion for logging now.
LatinImeLogger.onAddSuggestedWord("", Suggest.DIC_USER_TYPED, Dictionary.UNIGRAM);
mConsideredWord = "";
mBigramSuggestions = new ArrayList<SuggestedWordInfo>(PREF_MAX_BIGRAMS);
CharSequence lowerPrevWord = prevWordForBigram.toString().toLowerCase();
if (mMainDict != null && mMainDict.isValidWord(lowerPrevWord)) {
prevWordForBigram = lowerPrevWord;
}
for (final Dictionary dictionary : mBigramDictionaries.values()) {
dictionary.getBigrams(sEmptyWordComposer, prevWordForBigram, this);
}
// Nothing entered: return all bigrams for the previous word
int insertCount = Math.min(mBigramSuggestions.size(), mPrefMaxSuggestions);
for (int i = 0; i < insertCount; ++i) {
addBigramToSuggestions(mBigramSuggestions.get(i));
}
SuggestedWordInfo.removeDups(mSuggestions);
return new SuggestedWords(mSuggestions,
false /* typedWordValid */,
false /* hasAutoCorrectionCandidate */,
false /* allowsToBeAutoCorrected */,
false /* isPunctuationSuggestions */,
false /* isObsoleteSuggestions */);
}
// TODO: cleanup dictionaries looking up and suggestions building with SuggestedWords.Builder
public SuggestedWords getSuggestedWords(
final WordComposer wordComposer, CharSequence prevWordForBigram,
final ProximityInfo proximityInfo, final int correctionMode) {
LatinImeLogger.onStartSuggestion(prevWordForBigram);
mIsFirstCharCapitalized = wordComposer.isFirstCharCapitalized();
mIsAllUpperCase = wordComposer.isAllUpperCase();
mTrailingSingleQuotesCount = wordComposer.trailingSingleQuotesCount();
mSuggestions = new ArrayList<SuggestedWordInfo>(mPrefMaxSuggestions);
final String typedWord = wordComposer.getTypedWord();
final String consideredWord = mTrailingSingleQuotesCount > 0
? typedWord.substring(0, typedWord.length() - mTrailingSingleQuotesCount)
: typedWord;
// Treating USER_TYPED as UNIGRAM suggestion for logging now.
LatinImeLogger.onAddSuggestedWord(typedWord, Suggest.DIC_USER_TYPED, Dictionary.UNIGRAM);
mConsideredWord = consideredWord;
if (wordComposer.size() <= 1 && (correctionMode == CORRECTION_FULL_BIGRAM)) {
// At first character typed, search only the bigrams
mBigramSuggestions = new ArrayList<SuggestedWordInfo>(PREF_MAX_BIGRAMS);
if (!TextUtils.isEmpty(prevWordForBigram)) {
CharSequence lowerPrevWord = prevWordForBigram.toString().toLowerCase();
if (mMainDict != null && mMainDict.isValidWord(lowerPrevWord)) {
prevWordForBigram = lowerPrevWord;
}
for (final Dictionary dictionary : mBigramDictionaries.values()) {
dictionary.getBigrams(wordComposer, prevWordForBigram, this);
}
if (TextUtils.isEmpty(consideredWord)) {
// Nothing entered: return all bigrams for the previous word
int insertCount = Math.min(mBigramSuggestions.size(), mPrefMaxSuggestions);
for (int i = 0; i < insertCount; ++i) {
addBigramToSuggestions(mBigramSuggestions.get(i));
}
} else {
// Word entered: return only bigrams that match the first char of the typed word
final char currentChar = consideredWord.charAt(0);
// TODO: Must pay attention to locale when changing case.
// TODO: Use codepoint instead of char
final char currentCharUpper = Character.toUpperCase(currentChar);
int count = 0;
final int bigramSuggestionSize = mBigramSuggestions.size();
for (int i = 0; i < bigramSuggestionSize; i++) {
final SuggestedWordInfo bigramSuggestion = mBigramSuggestions.get(i);
final char bigramSuggestionFirstChar =
(char)bigramSuggestion.codePointAt(0);
if (bigramSuggestionFirstChar == currentChar
|| bigramSuggestionFirstChar == currentCharUpper) {
addBigramToSuggestions(bigramSuggestion);
if (++count > mPrefMaxSuggestions) break;
}
}
}
}
} else if (wordComposer.size() > 1) {
final WordComposer wordComposerForLookup;
if (mTrailingSingleQuotesCount > 0) {
wordComposerForLookup = new WordComposer(wordComposer);
for (int i = mTrailingSingleQuotesCount - 1; i >= 0; --i) {
wordComposerForLookup.deleteLast();
}
} else {
wordComposerForLookup = wordComposer;
}
// At second character typed, search the unigrams (scores being affected by bigrams)
for (final String key : mUnigramDictionaries.keySet()) {
// Skip UserUnigramDictionary and WhitelistDictionary to lookup
if (key.equals(DICT_KEY_USER_HISTORY_UNIGRAM) || key.equals(DICT_KEY_WHITELIST))
continue;
final Dictionary dictionary = mUnigramDictionaries.get(key);
dictionary.getWords(wordComposerForLookup, this, proximityInfo);
}
}
final CharSequence whitelistedWord = capitalizeWord(mIsAllUpperCase,
mIsFirstCharCapitalized, mWhiteListDictionary.getWhitelistedWord(consideredWord));
final boolean hasAutoCorrection;
if (CORRECTION_FULL == correctionMode || CORRECTION_FULL_BIGRAM == correctionMode) {
final CharSequence autoCorrection =
AutoCorrection.computeAutoCorrectionWord(mUnigramDictionaries, wordComposer,
mSuggestions, consideredWord, mAutoCorrectionThreshold,
whitelistedWord);
hasAutoCorrection = (null != autoCorrection);
} else {
hasAutoCorrection = false;
}
if (whitelistedWord != null) {
if (mTrailingSingleQuotesCount > 0) {
final StringBuilder sb = new StringBuilder(whitelistedWord);
for (int i = mTrailingSingleQuotesCount - 1; i >= 0; --i) {
sb.appendCodePoint(Keyboard.CODE_SINGLE_QUOTE);
}
mSuggestions.add(0, new SuggestedWordInfo(
sb.toString(), SuggestedWordInfo.MAX_SCORE));
} else {
mSuggestions.add(0, new SuggestedWordInfo(
whitelistedWord, SuggestedWordInfo.MAX_SCORE));
}
}
mSuggestions.add(0, new SuggestedWordInfo(typedWord, SuggestedWordInfo.MAX_SCORE));
SuggestedWordInfo.removeDups(mSuggestions);
final ArrayList<SuggestedWordInfo> suggestionsList;
if (DBG) {
suggestionsList = getSuggestionsInfoListWithDebugInfo(typedWord, mSuggestions);
} else {
suggestionsList = mSuggestions;
}
// TODO: Change this scheme - a boolean is not enough. A whitelisted word may be "valid"
// but still autocorrected from - in the case the whitelist only capitalizes the word.
// The whitelist should be case-insensitive, so it's not possible to be consistent with
// a boolean flag. Right now this is handled with a slight hack in
// WhitelistDictionary#shouldForciblyAutoCorrectFrom.
final boolean allowsToBeAutoCorrected = AutoCorrection.allowsToBeAutoCorrected(
getUnigramDictionaries(), consideredWord, wordComposer.isFirstCharCapitalized());
boolean autoCorrectionAvailable = hasAutoCorrection;
if (correctionMode == CORRECTION_FULL || correctionMode == CORRECTION_FULL_BIGRAM) {
autoCorrectionAvailable |= !allowsToBeAutoCorrected;
}
// Don't auto-correct words with multiple capital letter
autoCorrectionAvailable &= !wordComposer.isMostlyCaps();
if (allowsToBeAutoCorrected && suggestionsList.size() > 1 && mAutoCorrectionThreshold > 0
&& Suggest.shouldBlockAutoCorrectionBySafetyNet(typedWord,
suggestionsList.get(1).mWord)) {
autoCorrectionAvailable = false;
}
return new SuggestedWords(suggestionsList,
!allowsToBeAutoCorrected /* typedWordValid */,
autoCorrectionAvailable /* hasAutoCorrectionCandidate */,
allowsToBeAutoCorrected /* allowsToBeAutoCorrected */,
false /* isPunctuationSuggestions */,
false /* isObsoleteSuggestions */);
}
private static ArrayList<SuggestedWordInfo> getSuggestionsInfoListWithDebugInfo(
final String typedWord, final ArrayList<SuggestedWordInfo> suggestions) {
final SuggestedWordInfo typedWordInfo = suggestions.get(0);
typedWordInfo.setDebugString("+");
double normalizedScore = BinaryDictionary.calcNormalizedScore(
typedWord, typedWordInfo.toString(), typedWordInfo.mScore);
final int suggestionsSize = suggestions.size();
final ArrayList<SuggestedWordInfo> suggestionsList =
new ArrayList<SuggestedWordInfo>(suggestionsSize);
suggestionsList.add(typedWordInfo);
// Note: i here is the index in mScores[], but the index in mSuggestions is one more
// than i because we added the typed word to mSuggestions without touching mScores.
for (int i = 0; i < suggestionsSize - 1; ++i) {
final SuggestedWordInfo cur = suggestions.get(i + 1);
final String scoreInfoString;
if (normalizedScore > 0) {
scoreInfoString = String.format("%d (%4.2f)", cur.mScore, normalizedScore);
normalizedScore = 0.0;
} else {
scoreInfoString = Integer.toString(cur.mScore);
}
cur.setDebugString(scoreInfoString);
suggestionsList.add(cur);
}
return suggestionsList;
}
// TODO: Use codepoint instead of char
@Override
public boolean addWord(final char[] word, final int offset, final int length, int score,
final int dicTypeId, final int dataType) {
int dataTypeForLog = dataType;
final ArrayList<SuggestedWordInfo> suggestions;
final int prefMaxSuggestions;
if (dataType == Dictionary.BIGRAM) {
suggestions = mBigramSuggestions;
prefMaxSuggestions = PREF_MAX_BIGRAMS;
} else {
suggestions = mSuggestions;
prefMaxSuggestions = mPrefMaxSuggestions;
}
int pos = 0;
// Check if it's the same word, only caps are different
if (StringUtils.equalsIgnoreCase(mConsideredWord, word, offset, length)) {
// TODO: remove this surrounding if clause and move this logic to
// getSuggestedWordBuilder.
if (suggestions.size() > 0) {
final SuggestedWordInfo currentHighestWord = suggestions.get(0);
// If the current highest word is also equal to typed word, we need to compare
// frequency to determine the insertion position. This does not ensure strictly
// correct ordering, but ensures the top score is on top which is enough for
// removing duplicates correctly.
if (StringUtils.equalsIgnoreCase(currentHighestWord.mWord, word, offset, length)
&& score <= currentHighestWord.mScore) {
pos = 1;
}
}
} else {
if (dataType == Dictionary.UNIGRAM) {
// Check if the word was already added before (by bigram data)
int bigramSuggestion = searchBigramSuggestion(word,offset,length);
if(bigramSuggestion >= 0) {
dataTypeForLog = Dictionary.BIGRAM;
// turn freq from bigram into multiplier specified above
double multiplier = (((double) mBigramSuggestions.get(bigramSuggestion).mScore)
/ MAXIMUM_BIGRAM_FREQUENCY)
* (BIGRAM_MULTIPLIER_MAX - BIGRAM_MULTIPLIER_MIN)
+ BIGRAM_MULTIPLIER_MIN;
/* Log.d(TAG,"bigram num: " + bigramSuggestion
+ " wordB: " + mBigramSuggestions.get(bigramSuggestion).toString()
+ " currentScore: " + score + " bigramScore: "
+ mBigramScores[bigramSuggestion]
+ " multiplier: " + multiplier); */
score = (int)Math.round((score * multiplier));
}
}
// Check the last one's score and bail
if (suggestions.size() >= prefMaxSuggestions
&& suggestions.get(prefMaxSuggestions - 1).mScore >= score) return true;
while (pos < suggestions.size()) {
final int curScore = suggestions.get(pos).mScore;
if (curScore < score
|| (curScore == score && length < suggestions.get(pos).codePointCount())) {
break;
}
pos++;
}
}
if (pos >= prefMaxSuggestions) {
return true;
}
final StringBuilder sb = new StringBuilder(getApproxMaxWordLength());
// TODO: Must pay attention to locale when changing case.
if (mIsAllUpperCase) {
sb.append(new String(word, offset, length).toUpperCase());
} else if (mIsFirstCharCapitalized) {
sb.append(Character.toUpperCase(word[offset]));
if (length > 1) {
sb.append(word, offset + 1, length - 1);
}
} else {
sb.append(word, offset, length);
}
for (int i = mTrailingSingleQuotesCount - 1; i >= 0; --i) {
sb.appendCodePoint(Keyboard.CODE_SINGLE_QUOTE);
}
suggestions.add(pos, new SuggestedWordInfo(sb, score));
if (suggestions.size() > prefMaxSuggestions) {
suggestions.remove(prefMaxSuggestions);
} else {
LatinImeLogger.onAddSuggestedWord(sb.toString(), dicTypeId, dataTypeForLog);
}
return true;
}
// TODO: Use codepoint instead of char
private int searchBigramSuggestion(final char[] word, final int offset, final int length) {
// TODO This is almost O(n^2). Might need fix.
// search whether the word appeared in bigram data
int bigramSuggestSize = mBigramSuggestions.size();
for (int i = 0; i < bigramSuggestSize; i++) {
if (mBigramSuggestions.get(i).codePointCount() == length) {
boolean chk = true;
for (int j = 0; j < length; j++) {
if (mBigramSuggestions.get(i).codePointAt(j) != word[offset+j]) {
chk = false;
break;
}
}
if (chk) return i;
}
}
return -1;
}
public void close() {
final HashSet<Dictionary> dictionaries = new HashSet<Dictionary>();
dictionaries.addAll(mUnigramDictionaries.values());
dictionaries.addAll(mBigramDictionaries.values());
for (final Dictionary dictionary : dictionaries) {
dictionary.close();
}
mMainDict = null;
}
// TODO: Resolve the inconsistencies between the native auto correction algorithms and
// this safety net
public static boolean shouldBlockAutoCorrectionBySafetyNet(final String typedWord,
final CharSequence suggestion) {
// Safety net for auto correction.
// Actually if we hit this safety net, it's a bug.
// If user selected aggressive auto correction mode, there is no need to use the safety
// net.
// If the length of typed word is less than MINIMUM_SAFETY_NET_CHAR_LENGTH,
// we should not use net because relatively edit distance can be big.
final int typedWordLength = typedWord.length();
if (typedWordLength < Suggest.MINIMUM_SAFETY_NET_CHAR_LENGTH) {
return false;
}
final int maxEditDistanceOfNativeDictionary =
(typedWordLength < 5 ? 2 : typedWordLength / 2) + 1;
final int distance = BinaryDictionary.editDistance(typedWord, suggestion.toString());
if (DBG) {
Log.d(TAG, "Autocorrected edit distance = " + distance
+ ", " + maxEditDistanceOfNativeDictionary);
}
if (distance > maxEditDistanceOfNativeDictionary) {
if (DBG) {
Log.e(TAG, "Safety net: before = " + typedWord + ", after = " + suggestion);
Log.e(TAG, "(Error) The edit distance of this correction exceeds limit. "
+ "Turning off auto-correction.");
}
return true;
} else {
return false;
}
}
}