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 import android.annotation.UnsupportedAppUsage; 20 21 /** 22 * Singleton helper class for lazily initialization. 23 * 24 * Modeled after frameworks/base/include/utils/Singleton.h 25 * 26 * @hide 27 */ 28 public abstract class Singleton<T> { 29 @UnsupportedAppUsage 30 private T mInstance; 31 32 protected abstract T create(); 33 34 @UnsupportedAppUsage 35 public final T get() { 36 synchronized (this) { 37 if (mInstance == null) { 38 mInstance = create(); 39 } 40 return mInstance; 41 } 42 } 43 } 44
