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 17package androidx.arch.core.executor; 18 19import android.os.Handler; 20import android.os.Looper; 21 22import androidx.annotation.Nullable; 23import androidx.annotation.RestrictTo; 24 25import java.util.concurrent.ExecutorService; 26import java.util.concurrent.Executors; 27import java.util.concurrent.ThreadFactory; 28import java.util.concurrent.atomic.AtomicInteger; 29 30/** 31 * @hide 32 */ 33@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP) 34public class DefaultTaskExecutor extends TaskExecutor { 35 36 private final Object mLock = new Object(); 37 38 private final ExecutorService mDiskIO = Executors.newFixedThreadPool(2, new ThreadFactory() { 39 private static final String THREAD_NAME_STEM = "arch_disk_io_%d"; 40 41 private final AtomicInteger mThreadId = new AtomicInteger(0); 42 43 @Override 44 public Thread newThread(Runnable r) { 45 Thread t = new Thread(r); 46 t.setName(String.format(THREAD_NAME_STEM, mThreadId.getAndIncrement())); 47 return t; 48 } 49 }); 50 51 @Nullable 52 private volatile Handler mMainHandler; 53 54 @Override 55 public void executeOnDiskIO(Runnable runnable) { 56 mDiskIO.execute(runnable); 57 } 58 59 @Override 60 public void postToMainThread(Runnable runnable) { 61 if (mMainHandler == null) { 62 synchronized (mLock) { 63 if (mMainHandler == null) { 64 mMainHandler = new Handler(Looper.getMainLooper()); 65 } 66 } 67 } 68 //noinspection ConstantConditions 69 mMainHandler.post(runnable); 70 } 71 72 @Override 73 public boolean isMainThread() { 74 return Looper.getMainLooper().getThread() == Thread.currentThread(); 75 } 76} 77