Wei Hua | 1dd8ef5 | 2012-03-30 15:15:12 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 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 | |
| 17 | package android.bordeaux.services; |
| 18 | |
| 19 | import android.content.ContentValues; |
| 20 | import android.content.Context; |
| 21 | import android.database.Cursor; |
| 22 | import android.database.SQLException; |
| 23 | import android.database.sqlite.SQLiteDatabase; |
| 24 | import android.database.sqlite.SQLiteOpenHelper; |
| 25 | import android.util.Log; |
| 26 | |
| 27 | import java.lang.System; |
| 28 | import java.util.concurrent.ConcurrentHashMap; |
| 29 | |
| 30 | // This class manages the database for storing the session data. |
| 31 | // |
| 32 | class BordeauxSessionStorage { |
| 33 | |
| 34 | private static final String TAG = "BordeauxSessionStorage"; |
| 35 | // unique key for the session |
| 36 | public static final String COLUMN_KEY = "key"; |
| 37 | // name of the learning class |
| 38 | public static final String COLUMN_CLASS = "class"; |
| 39 | // data of the learning model |
| 40 | public static final String COLUMN_MODEL = "model"; |
| 41 | // last update time |
| 42 | public static final String COLUMN_TIME = "time"; |
| 43 | |
| 44 | private static final String DATABASE_NAME = "bordeaux"; |
| 45 | private static final String SESSION_TABLE = "sessions"; |
| 46 | private static final int DATABASE_VERSION = 1; |
| 47 | private static final String DATABASE_CREATE = |
| 48 | "create table " + SESSION_TABLE + "( " + COLUMN_KEY + |
| 49 | " TEXT primary key, " + COLUMN_CLASS + " TEXT, " + |
| 50 | COLUMN_MODEL + " BLOB, " + COLUMN_TIME + " INTEGER);"; |
| 51 | |
| 52 | private SessionDBHelper mDbHelper; |
| 53 | private SQLiteDatabase mDbSessions; |
| 54 | |
| 55 | BordeauxSessionStorage(final Context context) { |
| 56 | try { |
| 57 | mDbHelper = new SessionDBHelper(context); |
| 58 | mDbSessions = mDbHelper.getWritableDatabase(); |
| 59 | } catch (SQLException e) { |
| 60 | throw new RuntimeException("Can't open session database"); |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | private class SessionDBHelper extends SQLiteOpenHelper { |
| 65 | SessionDBHelper(Context context) { |
| 66 | super(context, DATABASE_NAME, null, DATABASE_VERSION); |
| 67 | } |
| 68 | |
| 69 | @Override |
| 70 | public void onCreate(SQLiteDatabase db) { |
| 71 | db.execSQL(DATABASE_CREATE); |
| 72 | } |
| 73 | |
| 74 | @Override |
| 75 | public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { |
| 76 | Log.w(TAG, "Upgrading database from version " + oldVersion + " to " |
| 77 | + newVersion + ", which will destroy all old data"); |
| 78 | |
| 79 | db.execSQL("DROP TABLE IF EXISTS " + SESSION_TABLE); |
| 80 | onCreate(db); |
| 81 | } |
| 82 | } |
| 83 | |
| 84 | private ContentValues createSessionEntry(String key, Class learner, byte[] model) { |
| 85 | ContentValues entry = new ContentValues(); |
| 86 | entry.put(COLUMN_KEY, key); |
| 87 | entry.put(COLUMN_TIME, System.currentTimeMillis()); |
| 88 | entry.put(COLUMN_MODEL, model); |
| 89 | entry.put(COLUMN_CLASS, learner.getName()); |
| 90 | return entry; |
| 91 | } |
| 92 | |
| 93 | boolean saveSession(String key, Class learner, byte[] model) { |
| 94 | ContentValues content = createSessionEntry(key, learner, model); |
| 95 | long rowID = |
| 96 | mDbSessions.insertWithOnConflict(SESSION_TABLE, null, content, |
| 97 | SQLiteDatabase.CONFLICT_REPLACE); |
| 98 | return rowID >= 0; |
| 99 | } |
| 100 | |
| 101 | private BordeauxSessionManager.Session getSessionFromCursor(Cursor cursor) { |
| 102 | BordeauxSessionManager.Session session = new BordeauxSessionManager.Session(); |
| 103 | String className = cursor.getString(cursor.getColumnIndex(COLUMN_CLASS)); |
| 104 | try { |
| 105 | session.learnerClass = Class.forName(className); |
| 106 | session.learner = (IBordeauxLearner) session.learnerClass.getConstructor().newInstance(); |
| 107 | } catch (Exception e) { |
| 108 | throw new RuntimeException("Can't instantiate class: " + className); |
| 109 | } |
| 110 | byte[] model = cursor.getBlob(cursor.getColumnIndex(COLUMN_MODEL)); |
| 111 | session.learner.setModel(model); |
| 112 | return session; |
| 113 | } |
| 114 | |
| 115 | BordeauxSessionManager.Session getSession(String key) { |
| 116 | Cursor cursor = mDbSessions.query(true, SESSION_TABLE, |
| 117 | new String[]{COLUMN_KEY, COLUMN_CLASS, COLUMN_MODEL, COLUMN_TIME}, |
| 118 | COLUMN_KEY + "=\"" + key + "\"", null, null, null, null, null); |
saberian | 984e52f | 2012-06-05 18:23:53 -0700 | [diff] [blame] | 119 | if ((cursor == null) | (cursor.getCount() == 0)) { |
| 120 | cursor.close(); |
| 121 | return null; |
| 122 | } |
Wei Hua | 1dd8ef5 | 2012-03-30 15:15:12 -0700 | [diff] [blame] | 123 | if (cursor.getCount() > 1) { |
saberian | 984e52f | 2012-06-05 18:23:53 -0700 | [diff] [blame] | 124 | cursor.close(); |
Wei Hua | 1dd8ef5 | 2012-03-30 15:15:12 -0700 | [diff] [blame] | 125 | throw new RuntimeException("Unexpected duplication in session table for key:" + key); |
| 126 | } |
| 127 | cursor.moveToFirst(); |
saberian | 984e52f | 2012-06-05 18:23:53 -0700 | [diff] [blame] | 128 | BordeauxSessionManager.Session s = getSessionFromCursor(cursor); |
| 129 | cursor.close(); |
| 130 | return s; |
Wei Hua | 1dd8ef5 | 2012-03-30 15:15:12 -0700 | [diff] [blame] | 131 | } |
| 132 | |
| 133 | void getAllSessions(ConcurrentHashMap<String, BordeauxSessionManager.Session> sessions) { |
| 134 | Cursor cursor = mDbSessions.rawQuery("select * from ?;", new String[]{SESSION_TABLE}); |
| 135 | if (cursor == null) return; |
Wei Hua | 2fc454f | 2012-08-24 16:06:41 -0700 | [diff] [blame^] | 136 | cursor.moveToFirst(); |
Wei Hua | 1dd8ef5 | 2012-03-30 15:15:12 -0700 | [diff] [blame] | 137 | do { |
| 138 | String key = cursor.getString(cursor.getColumnIndex(COLUMN_KEY)); |
| 139 | BordeauxSessionManager.Session session = getSessionFromCursor(cursor); |
| 140 | sessions.put(key, session); |
| 141 | } while (cursor.moveToNext()); |
| 142 | } |
| 143 | |
| 144 | // remove all sessions that have the key that matches the given sql regular |
| 145 | // expression. |
| 146 | int removeSessions(String reKey) { |
| 147 | int nDeleteRows = mDbSessions.delete(SESSION_TABLE, "? like \"?\"", |
| 148 | new String[]{COLUMN_KEY, reKey}); |
| 149 | Log.i(TAG, "Number of rows in session table deleted: " + nDeleteRows); |
| 150 | return nDeleteRows; |
| 151 | } |
| 152 | } |