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.server; 18 19 import android.os.Handler; 20 21 /** 22 * Shared singleton foreground thread for the system. This is a thread for regular 23 * foreground service operations, which shouldn't be blocked by anything running in 24 * the background. In particular, the shared background thread could be doing 25 * relatively long-running operations like saving state to disk (in addition to 26 * simply being a background priority), which can cause operations scheduled on it 27 * to be delayed for a user-noticeable amount of time. 28 */ 29 public final class FgThread extends ServiceThread { 30 private static FgThread sInstance; 31 private static Handler sHandler; 32 33 private FgThread() { 34 super("android.fg", android.os.Process.THREAD_PRIORITY_DEFAULT, true /*allowIo*/); 35 } 36 37 private static void ensureThreadLocked() { 38 if (sInstance == null) { 39 sInstance = new FgThread(); 40 sInstance.start(); 41 sHandler = new Handler(sInstance.getLooper()); 42 } 43 } 44 45 public static FgThread get() { 46 synchronized (UiThread.class) { 47 ensureThreadLocked(); 48 return sInstance; 49 } 50 } 51 52 public static Handler getHandler() { 53 synchronized (UiThread.class) { 54 ensureThreadLocked(); 55 return sHandler; 56 } 57 } 58 } 59