1 files changed, 250 insertions, 0 deletions
diff --git a/java/src/com/android/inputmethod/latin/UserUnigramDictionary.java b/java/src/com/android/inputmethod/latin/UserUnigramDictionary.java
new file mode 100644
index 000000000..382d64030
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/UserUnigramDictionary.java
@@ -0,0 +1,250 @@
+/*
+ * Copyright (C) 2010 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.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+import android.database.sqlite.SQLiteQueryBuilder;
+import android.os.AsyncTask;
+import android.provider.BaseColumns;
+import android.util.Log;
+
+import java.util.HashMap;
+import java.util.Map.Entry;
+import java.util.Set;
+
+/**
+ * This class (inherited from the old AutoDictionary) is used for user history
+ * based dictionary. It stores words that the user typed to supply a provision
+ * for suggesting and re-ordering of candidates.
+ */
+public class UserUnigramDictionary extends ExpandableDictionary {
+    // Weight added to a user picking a new word from the suggestion strip
+    static final int FREQUENCY_FOR_PICKED = 3;
+    // Weight added to a user typing a new word that doesn't get corrected (or is reverted)
+    static final int FREQUENCY_FOR_TYPED = 1;
+    // If the user touches a typed word 2 times or more, it will become valid.
+    private static final int VALIDITY_THRESHOLD = 2 * FREQUENCY_FOR_PICKED;
+
+    private LatinIME mIme;
+    // Locale for which this user unigram dictionary is storing words
+    private String mLocale;
+
+    private HashMap<String,Integer> mPendingWrites = new HashMap<String,Integer>();
+    private final Object mPendingWritesLock = new Object();
+
+    // TODO: we should probably change the database name
+    private static final String DATABASE_NAME = "auto_dict.db";
+    private static final int DATABASE_VERSION = 1;
+
+    // These are the columns in the dictionary
+    // TODO: Consume less space by using a unique id for locale instead of the whole
+    // 2-5 character string.
+    private static final String COLUMN_ID = BaseColumns._ID;
+    private static final String COLUMN_WORD = "word";
+    private static final String COLUMN_FREQUENCY = "freq";
+    private static final String COLUMN_LOCALE = "locale";
+
+    /** Sort by descending order of frequency. */
+    public static final String DEFAULT_SORT_ORDER = COLUMN_FREQUENCY + " DESC";
+
+    /** Name of the words table in the database */
+    private static final String USER_UNIGRAM_DICT_TABLE_NAME = "words";
+
+    private static HashMap<String, String> sDictProjectionMap;
+
+    static {
+        sDictProjectionMap = new HashMap<String, String>();
+        sDictProjectionMap.put(COLUMN_ID, COLUMN_ID);
+        sDictProjectionMap.put(COLUMN_WORD, COLUMN_WORD);
+        sDictProjectionMap.put(COLUMN_FREQUENCY, COLUMN_FREQUENCY);
+        sDictProjectionMap.put(COLUMN_LOCALE, COLUMN_LOCALE);
+    }
+
+    private static DatabaseHelper sOpenHelper = null;
+
+    public UserUnigramDictionary(Context context, LatinIME ime, String locale, int dicTypeId) {
+        super(context, dicTypeId);
+        mIme = ime;
+        mLocale = locale;
+        if (sOpenHelper == null) {
+            sOpenHelper = new DatabaseHelper(getContext());
+        }
+        if (mLocale != null && mLocale.length() > 1) {
+            loadDictionary();
+        }
+    }
+
+    @Override
+    public synchronized boolean isValidWord(CharSequence word) {
+        final int frequency = getWordFrequency(word);
+        return frequency >= VALIDITY_THRESHOLD;
+    }
+
+    @Override
+    public void close() {
+        flushPendingWrites();
+        // Don't close the database as locale changes will require it to be reopened anyway
+        // Also, the database is written to somewhat frequently, so it needs to be kept alive
+        // throughout the life of the process.
+        // mOpenHelper.close();
+        super.close();
+    }
+
+    @Override
+    public void loadDictionaryAsync() {
+        // Load the words that correspond to the current input locale
+        Cursor cursor = query(COLUMN_LOCALE + "=?", new String[] { mLocale });
+        try {
+            if (cursor.moveToFirst()) {
+                int wordIndex = cursor.getColumnIndex(COLUMN_WORD);
+                int frequencyIndex = cursor.getColumnIndex(COLUMN_FREQUENCY);
+                while (!cursor.isAfterLast()) {
+                    String word = cursor.getString(wordIndex);
+                    int frequency = cursor.getInt(frequencyIndex);
+                    // Safeguard against adding really long words. Stack may overflow due
+                    // to recursive lookup
+                    if (word.length() < getMaxWordLength()) {
+                        super.addWord(word, frequency);
+                    }
+                    cursor.moveToNext();
+                }
+            }
+        } finally {
+            cursor.close();
+        }
+    }
+
+    @Override
+    public void addWord(String newWord, int addFrequency) {
+        String word = newWord;
+        final int length = word.length();
+        // Don't add very short or very long words.
+        if (length < 2 || length > getMaxWordLength()) return;
+        if (mIme.getCurrentWord().isAutoCapitalized()) {
+            // Remove caps before adding
+            word = Character.toLowerCase(word.charAt(0)) + word.substring(1);
+        }
+        int freq = getWordFrequency(word);
+        freq = freq < 0 ? addFrequency : freq + addFrequency;
+        super.addWord(word, freq);
+
+        synchronized (mPendingWritesLock) {
+            // Write a null frequency if it is to be deleted from the db
+            mPendingWrites.put(word, freq == 0 ? null : new Integer(freq));
+        }
+    }
+
+    /**
+     * Schedules a background thread to write any pending words to the database.
+     */
+    public void flushPendingWrites() {
+        synchronized (mPendingWritesLock) {
+            // Nothing pending? Return
+            if (mPendingWrites.isEmpty()) return;
+            // Create a background thread to write the pending entries
+            new UpdateDbTask(getContext(), sOpenHelper, mPendingWrites, mLocale).execute();
+            // Create a new map for writing new entries into while the old one is written to db
+            mPendingWrites = new HashMap<String, Integer>();
+        }
+    }
+
+    /**
+     * This class helps open, create, and upgrade the database file.
+     */
+    private static class DatabaseHelper extends SQLiteOpenHelper {
+
+        DatabaseHelper(Context context) {
+            super(context, DATABASE_NAME, null, DATABASE_VERSION);
+        }
+
+        @Override
+        public void onCreate(SQLiteDatabase db) {
+            db.execSQL("CREATE TABLE " + USER_UNIGRAM_DICT_TABLE_NAME + " ("
+                    + COLUMN_ID + " INTEGER PRIMARY KEY,"
+                    + COLUMN_WORD + " TEXT,"
+                    + COLUMN_FREQUENCY + " INTEGER,"
+                    + COLUMN_LOCALE + " TEXT"
+                    + ");");
+        }
+
+        @Override
+        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+            Log.w("UserUnigramDictionary", "Upgrading database from version " + oldVersion + " to "
+                    + newVersion + ", which will destroy all old data");
+            db.execSQL("DROP TABLE IF EXISTS " + USER_UNIGRAM_DICT_TABLE_NAME);
+            onCreate(db);
+        }
+    }
+
+    private Cursor query(String selection, String[] selectionArgs) {
+        SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
+        qb.setTables(USER_UNIGRAM_DICT_TABLE_NAME);
+        qb.setProjectionMap(sDictProjectionMap);
+
+        // Get the database and run the query
+        SQLiteDatabase db = sOpenHelper.getReadableDatabase();
+        Cursor c = qb.query(db, null, selection, selectionArgs, null, null,
+                DEFAULT_SORT_ORDER);
+        return c;
+    }
+
+    /**
+     * Async task to write pending words to the database so that it stays in sync with
+     * the in-memory trie.
+     */
+    private static class UpdateDbTask extends AsyncTask<Void, Void, Void> {
+        private final HashMap<String, Integer> mMap;
+        private final DatabaseHelper mDbHelper;
+        private final String mLocale;
+
+        public UpdateDbTask(@SuppressWarnings("unused") Context context, DatabaseHelper openHelper,
+                HashMap<String, Integer> pendingWrites, String locale) {
+            mMap = pendingWrites;
+            mLocale = locale;
+            mDbHelper = openHelper;
+        }
+
+        @Override
+        protected Void doInBackground(Void... v) {
+            SQLiteDatabase db = mDbHelper.getWritableDatabase();
+            // Write all the entries to the db
+            Set<Entry<String,Integer>> mEntries = mMap.entrySet();
+            for (Entry<String,Integer> entry : mEntries) {
+                Integer freq = entry.getValue();
+                db.delete(USER_UNIGRAM_DICT_TABLE_NAME, COLUMN_WORD + "=? AND " + COLUMN_LOCALE
+                        + "=?", new String[] { entry.getKey(), mLocale });
+                if (freq != null) {
+                    db.insert(USER_UNIGRAM_DICT_TABLE_NAME, null,
+                            getContentValues(entry.getKey(), freq, mLocale));
+                }
+            }
+            return null;
+        }
+
+        private ContentValues getContentValues(String word, int frequency, String locale) {
+            ContentValues values = new ContentValues(4);
+            values.put(COLUMN_WORD, word);
+            values.put(COLUMN_FREQUENCY, frequency);
+            values.put(COLUMN_LOCALE, locale);
+            return values;
+        }
+    }
+}