| /* |
| * Copyright (C) 2012 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 android.bordeaux.services; |
| |
| import android.content.ContentValues; |
| import android.content.Context; |
| import android.database.Cursor; |
| import android.database.SQLException; |
| import android.database.sqlite.SQLiteDatabase; |
| import android.database.sqlite.SQLiteOpenHelper; |
| import android.util.Log; |
| |
| import java.lang.System; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| // This class manages the database for storing the session data. |
| // |
| class BordeauxSessionStorage { |
| |
| private static final String TAG = "BordeauxSessionStorage"; |
| // unique key for the session |
| public static final String COLUMN_KEY = "key"; |
| // name of the learning class |
| public static final String COLUMN_CLASS = "class"; |
| // data of the learning model |
| public static final String COLUMN_MODEL = "model"; |
| // last update time |
| public static final String COLUMN_TIME = "time"; |
| |
| private static final String DATABASE_NAME = "bordeaux"; |
| private static final String SESSION_TABLE = "sessions"; |
| private static final int DATABASE_VERSION = 1; |
| private static final String DATABASE_CREATE = |
| "create table " + SESSION_TABLE + "( " + COLUMN_KEY + |
| " TEXT primary key, " + COLUMN_CLASS + " TEXT, " + |
| COLUMN_MODEL + " BLOB, " + COLUMN_TIME + " INTEGER);"; |
| |
| private SessionDBHelper mDbHelper; |
| private SQLiteDatabase mDbSessions; |
| |
| BordeauxSessionStorage(final Context context) { |
| try { |
| mDbHelper = new SessionDBHelper(context); |
| mDbSessions = mDbHelper.getWritableDatabase(); |
| } catch (SQLException e) { |
| throw new RuntimeException("Can't open session database"); |
| } |
| } |
| |
| private class SessionDBHelper extends SQLiteOpenHelper { |
| SessionDBHelper(Context context) { |
| super(context, DATABASE_NAME, null, DATABASE_VERSION); |
| } |
| |
| @Override |
| public void onCreate(SQLiteDatabase db) { |
| db.execSQL(DATABASE_CREATE); |
| } |
| |
| @Override |
| public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { |
| Log.w(TAG, "Upgrading database from version " + oldVersion + " to " |
| + newVersion + ", which will destroy all old data"); |
| |
| db.execSQL("DROP TABLE IF EXISTS " + SESSION_TABLE); |
| onCreate(db); |
| } |
| } |
| |
| private ContentValues createSessionEntry(String key, Class learner, byte[] model) { |
| ContentValues entry = new ContentValues(); |
| entry.put(COLUMN_KEY, key); |
| entry.put(COLUMN_TIME, System.currentTimeMillis()); |
| entry.put(COLUMN_MODEL, model); |
| entry.put(COLUMN_CLASS, learner.getName()); |
| return entry; |
| } |
| |
| boolean saveSession(String key, Class learner, byte[] model) { |
| ContentValues content = createSessionEntry(key, learner, model); |
| long rowID = |
| mDbSessions.insertWithOnConflict(SESSION_TABLE, null, content, |
| SQLiteDatabase.CONFLICT_REPLACE); |
| return rowID >= 0; |
| } |
| |
| private BordeauxSessionManager.Session getSessionFromCursor(Cursor cursor) { |
| BordeauxSessionManager.Session session = new BordeauxSessionManager.Session(); |
| String className = cursor.getString(cursor.getColumnIndex(COLUMN_CLASS)); |
| try { |
| session.learnerClass = Class.forName(className); |
| session.learner = (IBordeauxLearner) session.learnerClass.getConstructor().newInstance(); |
| } catch (Exception e) { |
| throw new RuntimeException("Can't instantiate class: " + className); |
| } |
| byte[] model = cursor.getBlob(cursor.getColumnIndex(COLUMN_MODEL)); |
| session.learner.setModel(model); |
| return session; |
| } |
| |
| BordeauxSessionManager.Session getSession(String key) { |
| Cursor cursor = mDbSessions.query(true, SESSION_TABLE, |
| new String[]{COLUMN_KEY, COLUMN_CLASS, COLUMN_MODEL, COLUMN_TIME}, |
| COLUMN_KEY + "=\"" + key + "\"", null, null, null, null, null); |
| if ((cursor == null) | (cursor.getCount() == 0)) { |
| cursor.close(); |
| return null; |
| } |
| if (cursor.getCount() > 1) { |
| cursor.close(); |
| throw new RuntimeException("Unexpected duplication in session table for key:" + key); |
| } |
| cursor.moveToFirst(); |
| BordeauxSessionManager.Session s = getSessionFromCursor(cursor); |
| cursor.close(); |
| return s; |
| } |
| |
| void getAllSessions(ConcurrentHashMap<String, BordeauxSessionManager.Session> sessions) { |
| Cursor cursor = mDbSessions.rawQuery("select * from ?;", new String[]{SESSION_TABLE}); |
| if (cursor == null) return; |
| cursor.moveToFirst(); |
| do { |
| String key = cursor.getString(cursor.getColumnIndex(COLUMN_KEY)); |
| BordeauxSessionManager.Session session = getSessionFromCursor(cursor); |
| sessions.put(key, session); |
| } while (cursor.moveToNext()); |
| } |
| |
| // remove all sessions that have the key that matches the given sql regular |
| // expression. |
| int removeSessions(String reKey) { |
| int nDeleteRows = mDbSessions.delete(SESSION_TABLE, "? like \"?\"", |
| new String[]{COLUMN_KEY, reKey}); |
| Log.i(TAG, "Number of rows in session table deleted: " + nDeleteRows); |
| return nDeleteRows; |
| } |
| } |