AppBackupHelper.java

/*
 * Copyright (C) 2011 The original author or authors.
 * 
 * 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.zapta.apps.maniana.backup;

import java.io.IOException;

import android.app.backup.BackupAgentHelper;
import android.app.backup.BackupDataInput;
import android.app.backup.BackupDataOutput;
import android.app.backup.FileBackupHelper;
import android.app.backup.SharedPreferencesBackupHelper;
import android.os.ParcelFileDescriptor;

import com.zapta.apps.maniana.annotations.BackupAgentScope;
import com.zapta.apps.maniana.persistence.ModelPersistence;
import com.zapta.apps.maniana.util.LogUtil;

/**
 * Google Backup/Restore service agent. Must be listed in the Android Manifest file of the app.
 * 
 * @author Tal Dayan
 * 
 *         Note: to Force backup run the following after a data change:<br>
 *         adb shell bmgr run
 */
@BackupAgentScope
public class AppBackupHelper extends BackupAgentHelper {

    /** Unique key of the data file backup helper */
    private static final String DATA_FILE_HELPER_KEY = "data_helper_key";

    /** Unique key of the preferences file backup helper */
    private static final String PREFERENCES_HELPER_KEY = "pref_helper_key";

    @Override
    public void onCreate() {
        LogUtil.info("Google backup agent: onCreate()");

        // Helper for serialized model data file.
        final FileBackupHelper dataFileHelper = new FileBackupHelper(this,
                ModelPersistence.DATA_FILE_NAME);
        addHelper(DATA_FILE_HELPER_KEY, dataFileHelper);

        // Helper for shared preferences file
        final String defaultPrefFile = getPackageName() + "_preferences";
        final SharedPreferencesBackupHelper preferencesFileHelper = new SharedPreferencesBackupHelper(
                getApplicationContext(), defaultPrefFile);
        addHelper(PREFERENCES_HELPER_KEY, preferencesFileHelper);
    }

    @Override
    public void onBackup(ParcelFileDescriptor oldState, BackupDataOutput data,
            ParcelFileDescriptor newState) throws IOException {
        LogUtil.info("Google backup agent: onBackup()");
        // TODO: do we need a lock also for the shared preferences?
        synchronized (ModelPersistence.sDataFileLock) {
            // Synchronized access to the data file to avoid corruption.
            super.onBackup(oldState, data, newState);
        }
    }

    @Override
    public void onRestore(BackupDataInput data, int appVersionCode, ParcelFileDescriptor newState)
            throws IOException {
        LogUtil.info("Google backup agent: onRestore()");
        // TODO: do we need a lock also for the shared preferences?
        synchronized (ModelPersistence.sDataFileLock) {
            // Synchronized access to the data file to avoid corruption.
            super.onRestore(data, appVersionCode, newState);
        }
    }
}