FgThread.java revision 4ccb823a9f62e57f9d221f83a97e82967e79a9e5
18d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn/* 28d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * Copyright (C) 2013 The Android Open Source Project 38d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * 48d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * Licensed under the Apache License, Version 2.0 (the "License"); 58d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * you may not use this file except in compliance with the License. 68d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * You may obtain a copy of the License at 78d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * 88d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * http://www.apache.org/licenses/LICENSE-2.0 98d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * 108d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * Unless required by applicable law or agreed to in writing, software 118d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * distributed under the License is distributed on an "AS IS" BASIS, 128d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 138d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * See the License for the specific language governing permissions and 148d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * limitations under the License. 158d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn */ 168d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn 178d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackbornpackage com.android.server; 188d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn 198d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackbornimport android.os.Handler; 208d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn 218d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn/** 228d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * Shared singleton foreground thread for the system. This is a thread for regular 238d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * foreground service operations, which shouldn't be blocked by anything running in 248d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * the background. In particular, the shared background thread could be doing 258d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * relatively long-running operations like saving state to disk (in addition to 268d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * simply being a background priority), which can cause operations scheduled on it 278d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn * to be delayed for a user-noticeable amount of time. 288d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn */ 294ccb823a9f62e57f9d221f83a97e82967e79a9e5Jeff Brownpublic final class FgThread extends ServiceThread { 308d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn private static FgThread sInstance; 318d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn private static Handler sHandler; 328d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn 338d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn private FgThread() { 344ccb823a9f62e57f9d221f83a97e82967e79a9e5Jeff Brown super("android.fg", android.os.Process.THREAD_PRIORITY_DEFAULT, true /*allowIo*/); 358d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn } 368d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn 378d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn private static void ensureThreadLocked() { 388d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn if (sInstance == null) { 398d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn sInstance = new FgThread(); 408d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn sInstance.start(); 418d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn sHandler = new Handler(sInstance.getLooper()); 428d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn } 438d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn } 448d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn 458d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn public static FgThread get() { 468d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn synchronized (UiThread.class) { 478d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn ensureThreadLocked(); 488d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn return sInstance; 498d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn } 508d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn } 518d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn 528d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn public static Handler getHandler() { 538d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn synchronized (UiThread.class) { 548d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn ensureThreadLocked(); 558d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn return sHandler; 568d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn } 578d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn } 588d044e8bc287c1a567d82aedbe30085b011544c3Dianne Hackborn} 59