1 /* 2 * Copyright (C) 2021 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.tv.settings.library.util; 18 19 import android.os.Handler; 20 import android.os.Looper; 21 22 import java.util.concurrent.Callable; 23 import java.util.concurrent.ExecutorService; 24 import java.util.concurrent.Executors; 25 import java.util.concurrent.Future; 26 27 public class ThreadUtils { 28 29 private static volatile Thread sMainThread; 30 private static volatile Handler sMainThreadHandler; 31 private static volatile ExecutorService sThreadExecutor; 32 33 /** 34 * Returns true if the current thread is the UI thread. 35 */ isMainThread()36 public static boolean isMainThread() { 37 if (sMainThread == null) { 38 sMainThread = Looper.getMainLooper().getThread(); 39 } 40 return Thread.currentThread() == sMainThread; 41 } 42 43 /** 44 * Returns a shared UI thread handler. 45 */ getUiThreadHandler()46 public static Handler getUiThreadHandler() { 47 if (sMainThreadHandler == null) { 48 sMainThreadHandler = new Handler(Looper.getMainLooper()); 49 } 50 51 return sMainThreadHandler; 52 } 53 54 /** 55 * Checks that the current thread is the UI thread. Otherwise throws an exception. 56 */ ensureMainThread()57 public static void ensureMainThread() { 58 if (!isMainThread()) { 59 throw new RuntimeException("Must be called on the UI thread"); 60 } 61 } 62 63 /** 64 * Posts runnable in background using shared background thread pool. 65 * 66 * @Return A future of the task that can be monitored for updates or cancelled. 67 */ postOnBackgroundThread(Runnable runnable)68 public static Future postOnBackgroundThread(Runnable runnable) { 69 return getThreadExecutor().submit(runnable); 70 } 71 72 /** 73 * Posts callable in background using shared background thread pool. 74 * 75 * @Return A future of the task that can be monitored for updates or cancelled. 76 */ postOnBackgroundThread(Callable callable)77 public static Future postOnBackgroundThread(Callable callable) { 78 return getThreadExecutor().submit(callable); 79 } 80 81 /** 82 * Posts the runnable on the main thread. 83 */ postOnMainThread(Runnable runnable)84 public static void postOnMainThread(Runnable runnable) { 85 getUiThreadHandler().post(runnable); 86 } 87 getThreadExecutor()88 private static synchronized ExecutorService getThreadExecutor() { 89 if (sThreadExecutor == null) { 90 sThreadExecutor = Executors.newFixedThreadPool( 91 Runtime.getRuntime().availableProcessors()); 92 } 93 return sThreadExecutor; 94 } 95 } 96