1 /*
2  * Copyright (C) 2010 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 
17 package android.util;
18 
19 /**
20  * Singleton helper class for lazily initialization.
21  *
22  * Modeled after frameworks/base/include/utils/Singleton.h
23  *
24  * @hide
25  */
26 public abstract class Singleton<T> {
27     private T mInstance;
28 
create()29     protected abstract T create();
30 
get()31     public final T get() {
32         synchronized (this) {
33             if (mInstance == null) {
34                 mInstance = create();
35             }
36             return mInstance;
37         }
38     }
39 }
40