1 /* 2 * Copyright (C) 2017 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 android.arch.core.executor; 18 19 import android.os.Handler; 20 import android.os.Looper; 21 import android.support.annotation.Nullable; 22 import android.support.annotation.RestrictTo; 23 24 import java.util.concurrent.ExecutorService; 25 import java.util.concurrent.Executors; 26 27 /** 28 * @hide 29 */ 30 @RestrictTo(RestrictTo.Scope.LIBRARY_GROUP) 31 public class DefaultTaskExecutor extends TaskExecutor { 32 private final Object mLock = new Object(); 33 private ExecutorService mDiskIO = Executors.newFixedThreadPool(2); 34 35 @Nullable 36 private volatile Handler mMainHandler; 37 38 @Override 39 public void executeOnDiskIO(Runnable runnable) { 40 mDiskIO.execute(runnable); 41 } 42 43 @Override 44 public void postToMainThread(Runnable runnable) { 45 if (mMainHandler == null) { 46 synchronized (mLock) { 47 if (mMainHandler == null) { 48 mMainHandler = new Handler(Looper.getMainLooper()); 49 } 50 } 51 } 52 //noinspection ConstantConditions 53 mMainHandler.post(runnable); 54 } 55 56 @Override 57 public boolean isMainThread() { 58 return Looper.getMainLooper().getThread() == Thread.currentThread(); 59 } 60 } 61