98 lines
3.7 KiB
Java
98 lines
3.7 KiB
Java
/*
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* Copyright (C) 2009 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.app.backup;
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import android.os.ParcelFileDescriptor;
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import java.io.IOException;
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/**
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* A convenient {@link BackupAgent} wrapper class that automatically manages
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* heterogeneous data sets within the backup data, each identified by a unique
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* key prefix. When processing a backup or restore operation, the BackupAgentHelper
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* dispatches to one or more installed {@link BackupHelper} objects, each
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* of which is responsible for a defined subset of the data being processed.
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* <p>
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* An application will typically extend this class in its own
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* backup agent. Then, within the agent's {@link BackupAgent#onCreate() onCreate()}
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* method, it will call {@link #addHelper(String, BackupHelper) addHelper()} one or more times to
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* install the handlers for each kind of data it wishes to manage within its backups.
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* <p>
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* The Android framework currently provides two predefined {@link BackupHelper} classes:</p>
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* <ul><li>{@link FileBackupHelper} - Manages the backup and restore of entire files
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* within an application's data directory hierarchy.</li>
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* <li>{@link SharedPreferencesBackupHelper} - Manages the backup and restore of an
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* application's {@link android.content.SharedPreferences} data.</li></ul>
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* <p>
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* An application can also implement its own helper classes to work within the
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* {@link BackupAgentHelper} framework. See the {@link BackupHelper} interface
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* documentation for details.
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*
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* <div class="special reference">
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* <h3>Developer Guides</h3>
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* <p>For more information about using BackupAgentHelper, read the
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* <a href="{@docRoot}guide/topics/data/backup.html">Data Backup</a> developer guide.</p>
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* </div>
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*
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* @see BackupHelper
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* @see FileBackupHelper
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* @see SharedPreferencesBackupHelper
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*/
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public class BackupAgentHelper extends BackupAgent {
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static final String TAG = "BackupAgentHelper";
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BackupHelperDispatcher mDispatcher = new BackupHelperDispatcher();
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/**
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* Run the backup process on each of the configured handlers.
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*/
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@Override
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public void onBackup(ParcelFileDescriptor oldState, BackupDataOutput data,
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ParcelFileDescriptor newState) throws IOException {
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mDispatcher.performBackup(oldState, data, newState);
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}
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/**
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* Run the restore process on each of the configured handlers.
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*/
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@Override
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public void onRestore(BackupDataInput data, int appVersionCode, ParcelFileDescriptor newState)
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throws IOException {
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mDispatcher.performRestore(data, appVersionCode, newState);
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}
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/** @hide */
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public BackupHelperDispatcher getDispatcher() {
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return mDispatcher;
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}
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/**
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* Add a helper for a given data subset to the agent's configuration. Each helper
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* must have a prefix string that is unique within this backup agent's set of
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* helpers.
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*
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* @param keyPrefix A string used to disambiguate the various helpers within this agent
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* @param helper A backup/restore helper object to be invoked during backup and restore
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* operations.
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*/
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public void addHelper(String keyPrefix, BackupHelper helper) {
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mDispatcher.addHelper(keyPrefix, helper);
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}
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}
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