BackupAgentHelper.java revision 4e14a829129feee14ebe453f61a124784c870610 
1/*
2 * Copyright (C) 2009 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
17package android.app.backup;
18
19import android.os.ParcelFileDescriptor;
20
21import java.io.IOException;
22
23/**
24 * A convenient BackupAgent wrapper class that automatically manages
25 * heterogeneous data sets within the backup data, each identified by a unique
26 * key prefix. An application will typically extend this class in their own
27 * backup agent. Then, within the agent's onBackup() and onRestore() methods, it
28 * will call {@link #addHelper(String, BackupHelper)} one or more times to
29 * specify the data sets, then invoke super.onBackup() or super.onRestore() to
30 * have the BackupAgentHelper implementation process the data.
31 * <p>
32 * STOPSHIP: document!
33 *
34 * @see FileBackupHelper
35 * @see SharedPreferencesBackupHelper
36 */
37public class BackupAgentHelper extends BackupAgent {
38    static final String TAG = "BackupAgentHelper";
39
40    BackupHelperDispatcher mDispatcher = new BackupHelperDispatcher();
41
42    /**
43     * Run the backup process on each of the configured handlers.
44     */
45    @Override
46    public void onBackup(ParcelFileDescriptor oldState, BackupDataOutput data,
47             ParcelFileDescriptor newState) throws IOException {
48        mDispatcher.performBackup(oldState, data, newState);
49    }
50
51    /**
52     * Run the restore process on each of the configured handlers.
53     */
54    @Override
55    public void onRestore(BackupDataInput data, int appVersionCode, ParcelFileDescriptor newState)
56            throws IOException {
57        mDispatcher.performRestore(data, appVersionCode, newState);
58    }
59
60    /** @hide */
61    public BackupHelperDispatcher getDispatcher() {
62        return mDispatcher;
63    }
64
65    /**
66     * Add a helper for a given data subset to the agent's configuration.  Each helper
67     * must have a prefix string that is unique within this backup agent's set of
68     * helpers.
69     *
70     * @param keyPrefix A string used to disambiguate the various helpers within this agent
71     * @param helper A backup/restore helper object to be invoked during backup and restore
72     *    operations.
73     */
74    public void addHelper(String keyPrefix, BackupHelper helper) {
75        mDispatcher.addHelper(keyPrefix, helper);
76    }
77}
78
79
80