1 /* 2 * Copyright (C) 2020 The Dagger Authors. 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 dagger.hilt.android.internal; 18 19 import android.os.Looper; 20 21 /** Thread utility methods. */ 22 public final class ThreadUtil { 23 24 private static Thread mainThread; 25 ThreadUtil()26 private ThreadUtil() {} 27 28 /** Returns true if the current thread is the Main thread. */ isMainThread()29 public static boolean isMainThread() { 30 if (mainThread == null) { 31 mainThread = Looper.getMainLooper().getThread(); 32 } 33 return Thread.currentThread() == mainThread; 34 } 35 36 /** Checks that the current thread is the Main thread. Otherwise throws an exception. */ ensureMainThread()37 public static void ensureMainThread() { 38 if (!isMainThread()) { 39 throw new IllegalStateException("Must be called on the Main thread."); 40 } 41 } 42 } 43