1 /* 2 * Copyright (C) 2012 Google Inc. 3 * Licensed to The Android Open Source Project. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package com.android.mail.preferences; 18 19 import android.content.Context; 20 21 import java.util.concurrent.atomic.AtomicBoolean; 22 23 /** 24 * Interface to allow migrating preferences from other projects into the UnifiedEmail code, so apps 25 * can slowly move their preferences into the shared code. 26 */ 27 public abstract class BasePreferenceMigrator { 28 /** If <code>true</code>, we have not attempted a migration since the app started. */ 29 private static final AtomicBoolean sMigrationNecessary = new AtomicBoolean(true); 30 31 public final boolean performMigration( 32 final Context context, final int oldVersion, final int newVersion) { 33 // Ensure we only run this once 34 if (sMigrationNecessary.getAndSet(false)) { 35 migrate(context, oldVersion, newVersion); 36 return true; 37 } 38 39 return false; 40 } 41 42 /** 43 * Migrates preferences to UnifiedEmail. 44 * 45 * @param oldVersion The previous version of UnifiedEmail's preferences 46 * @param newVersion The new version of UnifiedEmail's preferences 47 */ 48 protected abstract void migrate(final Context context, int oldVersion, int newVersion); 49 } 50
