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 
performMigration( final Context context, final int oldVersion, final int newVersion)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      */
migrate(final Context context, int oldVersion, int newVersion)48     protected abstract void migrate(final Context context, int oldVersion, int newVersion);
49 }
50