262 lines
10 KiB
Java
262 lines
10 KiB
Java
/*
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* Copyright (C) 2010 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy of
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* the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations under
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* the License.
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*/
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package com.android.inputmethod.latin;
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import android.content.ContentValues;
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import android.content.Context;
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import android.database.Cursor;
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import android.database.sqlite.SQLiteDatabase;
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import android.database.sqlite.SQLiteOpenHelper;
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import android.database.sqlite.SQLiteQueryBuilder;
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import android.os.AsyncTask;
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import android.provider.BaseColumns;
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import android.util.Log;
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import java.util.HashMap;
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import java.util.Map.Entry;
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import java.util.Set;
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/**
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* This class (inherited from the old AutoDictionary) is used for user history
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* based dictionary. It stores words that the user typed to supply a provision
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* for suggesting and re-ordering of candidates.
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*/
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public class UserUnigramDictionary extends ExpandableDictionary {
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static final boolean ENABLE_USER_UNIGRAM_DICTIONARY = false;
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// Weight added to a user picking a new word from the suggestion strip
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static final int FREQUENCY_FOR_PICKED = 3;
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// Weight added to a user typing a new word that doesn't get corrected (or is reverted)
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static final int FREQUENCY_FOR_TYPED = 1;
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// If the user touches a typed word 2 times or more, it will become valid.
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private static final int VALIDITY_THRESHOLD = 2 * FREQUENCY_FOR_PICKED;
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private LatinIME mIme;
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// Locale for which this user unigram dictionary is storing words
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private String mLocale;
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private HashMap<String,Integer> mPendingWrites = new HashMap<String,Integer>();
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private final Object mPendingWritesLock = new Object();
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// TODO: we should probably change the database name
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private static final String DATABASE_NAME = "auto_dict.db";
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private static final int DATABASE_VERSION = 1;
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// These are the columns in the dictionary
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// TODO: Consume less space by using a unique id for locale instead of the whole
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// 2-5 character string.
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private static final String COLUMN_ID = BaseColumns._ID;
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private static final String COLUMN_WORD = "word";
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private static final String COLUMN_FREQUENCY = "freq";
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private static final String COLUMN_LOCALE = "locale";
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/** Sort by descending order of frequency. */
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public static final String DEFAULT_SORT_ORDER = COLUMN_FREQUENCY + " DESC";
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/** Name of the words table in the database */
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private static final String USER_UNIGRAM_DICT_TABLE_NAME = "words";
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private static HashMap<String, String> sDictProjectionMap;
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static {
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if (ENABLE_USER_UNIGRAM_DICTIONARY) {
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sDictProjectionMap = new HashMap<String, String>();
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sDictProjectionMap.put(COLUMN_ID, COLUMN_ID);
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sDictProjectionMap.put(COLUMN_WORD, COLUMN_WORD);
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sDictProjectionMap.put(COLUMN_FREQUENCY, COLUMN_FREQUENCY);
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sDictProjectionMap.put(COLUMN_LOCALE, COLUMN_LOCALE);
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}
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}
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private static DatabaseHelper sOpenHelper = null;
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public UserUnigramDictionary(Context context, LatinIME ime, String locale, int dicTypeId) {
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super(context, dicTypeId);
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// Super must be first statement of the constructor... I'd like not to do it if the
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// user unigram dictionary is not enabled, but Java won't let me.
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if (!ENABLE_USER_UNIGRAM_DICTIONARY) return;
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mIme = ime;
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mLocale = locale;
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if (sOpenHelper == null) {
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sOpenHelper = new DatabaseHelper(getContext());
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}
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if (mLocale != null && mLocale.length() > 1) {
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loadDictionary();
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}
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}
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@Override
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public synchronized boolean isValidWord(CharSequence word) {
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if (!ENABLE_USER_UNIGRAM_DICTIONARY) return false;
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final int frequency = getWordFrequency(word);
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return frequency >= VALIDITY_THRESHOLD;
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}
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@Override
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public void close() {
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super.close();
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if (!ENABLE_USER_UNIGRAM_DICTIONARY) return;
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flushPendingWrites();
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// Don't close the database as locale changes will require it to be reopened anyway
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// Also, the database is written to somewhat frequently, so it needs to be kept alive
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// throughout the life of the process.
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// mOpenHelper.close();
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}
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@Override
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public void loadDictionaryAsync() {
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if (!ENABLE_USER_UNIGRAM_DICTIONARY) return;
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// Load the words that correspond to the current input locale
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Cursor cursor = query(COLUMN_LOCALE + "=?", new String[] { mLocale });
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try {
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if (cursor.moveToFirst()) {
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int wordIndex = cursor.getColumnIndex(COLUMN_WORD);
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int frequencyIndex = cursor.getColumnIndex(COLUMN_FREQUENCY);
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while (!cursor.isAfterLast()) {
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String word = cursor.getString(wordIndex);
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int frequency = cursor.getInt(frequencyIndex);
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// Safeguard against adding really long words. Stack may overflow due
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// to recursive lookup
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if (word.length() < getMaxWordLength()) {
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super.addWord(word, frequency);
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}
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cursor.moveToNext();
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}
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}
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} finally {
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cursor.close();
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}
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}
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@Override
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public void addWord(String newWord, int addFrequency) {
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if (!ENABLE_USER_UNIGRAM_DICTIONARY) return;
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String word = newWord;
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final int length = word.length();
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// Don't add very short or very long words.
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if (length < 2 || length > getMaxWordLength()) return;
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if (mIme.isAutoCapitalized()) {
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// Remove caps before adding
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word = Character.toLowerCase(word.charAt(0)) + word.substring(1);
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}
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int freq = getWordFrequency(word);
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freq = freq < 0 ? addFrequency : freq + addFrequency;
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super.addWord(word, freq);
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synchronized (mPendingWritesLock) {
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// Write a null frequency if it is to be deleted from the db
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mPendingWrites.put(word, freq == 0 ? null : new Integer(freq));
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}
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}
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/**
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* Schedules a background thread to write any pending words to the database.
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*/
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public void flushPendingWrites() {
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if (!ENABLE_USER_UNIGRAM_DICTIONARY) return;
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synchronized (mPendingWritesLock) {
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// Nothing pending? Return
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if (mPendingWrites.isEmpty()) return;
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// Create a background thread to write the pending entries
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new UpdateDbTask(sOpenHelper, mPendingWrites, mLocale).execute();
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// Create a new map for writing new entries into while the old one is written to db
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mPendingWrites = new HashMap<String, Integer>();
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}
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}
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/**
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* This class helps open, create, and upgrade the database file.
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*/
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private static class DatabaseHelper extends SQLiteOpenHelper {
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DatabaseHelper(Context context) {
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super(context, DATABASE_NAME, null, DATABASE_VERSION);
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}
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@Override
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public void onCreate(SQLiteDatabase db) {
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db.execSQL("CREATE TABLE " + USER_UNIGRAM_DICT_TABLE_NAME + " ("
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+ COLUMN_ID + " INTEGER PRIMARY KEY,"
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+ COLUMN_WORD + " TEXT,"
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+ COLUMN_FREQUENCY + " INTEGER,"
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+ COLUMN_LOCALE + " TEXT"
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+ ");");
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}
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@Override
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public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
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Log.w("UserUnigramDictionary", "Upgrading database from version " + oldVersion + " to "
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+ newVersion + ", which will destroy all old data");
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db.execSQL("DROP TABLE IF EXISTS " + USER_UNIGRAM_DICT_TABLE_NAME);
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onCreate(db);
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}
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}
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private static Cursor query(String selection, String[] selectionArgs) {
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SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
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qb.setTables(USER_UNIGRAM_DICT_TABLE_NAME);
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qb.setProjectionMap(sDictProjectionMap);
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// Get the database and run the query
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SQLiteDatabase db = sOpenHelper.getReadableDatabase();
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Cursor c = qb.query(db, null, selection, selectionArgs, null, null,
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DEFAULT_SORT_ORDER);
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return c;
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}
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/**
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* Async task to write pending words to the database so that it stays in sync with
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* the in-memory trie.
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*/
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private static class UpdateDbTask extends AsyncTask<Void, Void, Void> {
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private final HashMap<String, Integer> mMap;
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private final DatabaseHelper mDbHelper;
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private final String mLocale;
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public UpdateDbTask(DatabaseHelper openHelper, HashMap<String, Integer> pendingWrites,
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String locale) {
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mMap = pendingWrites;
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mLocale = locale;
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mDbHelper = openHelper;
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}
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@Override
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protected Void doInBackground(Void... v) {
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SQLiteDatabase db = mDbHelper.getWritableDatabase();
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// Write all the entries to the db
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Set<Entry<String,Integer>> mEntries = mMap.entrySet();
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for (Entry<String,Integer> entry : mEntries) {
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Integer freq = entry.getValue();
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db.delete(USER_UNIGRAM_DICT_TABLE_NAME, COLUMN_WORD + "=? AND " + COLUMN_LOCALE
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+ "=?", new String[] { entry.getKey(), mLocale });
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if (freq != null) {
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db.insert(USER_UNIGRAM_DICT_TABLE_NAME, null,
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getContentValues(entry.getKey(), freq, mLocale));
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}
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}
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return null;
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}
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private static ContentValues getContentValues(String word, int frequency, String locale) {
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ContentValues values = new ContentValues(4);
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values.put(COLUMN_WORD, word);
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values.put(COLUMN_FREQUENCY, frequency);
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values.put(COLUMN_LOCALE, locale);
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return values;
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}
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}
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}
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