/* * Copyright (C) 2009 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.app.backup; import android.os.ParcelFileDescriptor; import java.io.IOException; /** * A convenient {@link BackupAgent} wrapper class that automatically manages * heterogeneous data sets within the backup data, each identified by a unique * key prefix. When processing a backup or restore operation, the BackupAgentHelper * dispatches to one or more installed {@link BackupHelper} objects, each * of which is responsible for a defined subset of the data being processed. *

* An application will typically extend this class in its own * backup agent. Then, within the agent's {@link BackupAgent#onCreate() onCreate()} * method, it will call {@link #addHelper(String, BackupHelper) addHelper()} one or more times to * install the handlers for each kind of data it wishes to manage within its backups. *

* The Android framework currently provides two predefined {@link BackupHelper} classes:

* *

* An application can also implement its own helper classes to work within the * {@link BackupAgentHelper} framework. See the {@link BackupHelper} interface * documentation for details. * *

*

Developer Guides

*

For more information about using BackupAgentHelper, read the * Data Backup developer guide.

*
* * @see BackupHelper * @see FileBackupHelper * @see SharedPreferencesBackupHelper */ public class BackupAgentHelper extends BackupAgent { static final String TAG = "BackupAgentHelper"; BackupHelperDispatcher mDispatcher = new BackupHelperDispatcher(); /** * Run the backup process on each of the configured handlers. */ @Override public void onBackup(ParcelFileDescriptor oldState, BackupDataOutput data, ParcelFileDescriptor newState) throws IOException { mDispatcher.performBackup(oldState, data, newState); } /** * Run the restore process on each of the configured handlers. */ @Override public void onRestore(BackupDataInput data, int appVersionCode, ParcelFileDescriptor newState) throws IOException { mDispatcher.performRestore(data, appVersionCode, newState); } /** @hide */ public BackupHelperDispatcher getDispatcher() { return mDispatcher; } /** * Add a helper for a given data subset to the agent's configuration. Each helper * must have a prefix string that is unique within this backup agent's set of * helpers. * * @param keyPrefix A string used to disambiguate the various helpers within this agent * @param helper A backup/restore helper object to be invoked during backup and restore * operations. */ public void addHelper(String keyPrefix, BackupHelper helper) { mDispatcher.addHelper(keyPrefix, helper); } }