1 /* 2 * Copyright (C) 2013 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 com.android.internal.os; 18 19 import android.os.Handler; 20 import android.os.HandlerThread; 21 import android.os.Trace; 22 23 /** 24 * Shared singleton background thread for each process. 25 */ 26 public final class BackgroundThread extends HandlerThread { 27 private static BackgroundThread sInstance; 28 private static Handler sHandler; 29 BackgroundThread()30 private BackgroundThread() { 31 super("android.bg", android.os.Process.THREAD_PRIORITY_BACKGROUND); 32 } 33 ensureThreadLocked()34 private static void ensureThreadLocked() { 35 if (sInstance == null) { 36 sInstance = new BackgroundThread(); 37 sInstance.start(); 38 sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_ACTIVITY_MANAGER); 39 sHandler = new Handler(sInstance.getLooper()); 40 } 41 } 42 get()43 public static BackgroundThread get() { 44 synchronized (BackgroundThread.class) { 45 ensureThreadLocked(); 46 return sInstance; 47 } 48 } 49 getHandler()50 public static Handler getHandler() { 51 synchronized (BackgroundThread.class) { 52 ensureThreadLocked(); 53 return sHandler; 54 } 55 } 56 } 57