content: /*
   * 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.
   * <p>
   * 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.
   * <p>
   * The Android framework currently provides two predefined {@link BackupHelper} classes:</p>
   * <ul><li>{@link FileBackupHelper} - Manages the backup and restore of entire files
   * within an application's data directory hierarchy.</li>
   * <li>{@link SharedPreferencesBackupHelper} - Manages the backup and restore of an
   * application's {@link android.content.SharedPreferences} data.</li></ul>
   * <p>
   * An application can also implement its own helper classes to work within the
   * {@link BackupAgentHelper} framework.  See the {@link BackupHelper} interface
   * documentation for details.
   *
   * <div class="special reference">
   * <h3>Developer Guides</h3>
   * <p>For more information about using BackupAgentHelper, read the
   * <a href="{@docRoot}guide/topics/data/backup.html">Data Backup</a> developer guide.</p>
   * </div>
   *
   * @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);
      }
  }
  
  
  