1 /*
2  * Copyright (C) 2008 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 package com.android.launcher3.util;
17 
18 import android.os.HandlerThread;
19 import android.os.Looper;
20 import android.os.Process;
21 
22 import java.util.concurrent.LinkedBlockingQueue;
23 import java.util.concurrent.ThreadPoolExecutor;
24 import java.util.concurrent.TimeUnit;
25 
26 /**
27  * Various different executors used in Launcher
28  */
29 public class Executors {
30 
31     // These values are same as that in {@link AsyncTask}.
32     private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();
33     private static final int CORE_POOL_SIZE = CPU_COUNT + 1;
34     private static final int MAXIMUM_POOL_SIZE = CPU_COUNT * 2 + 1;
35     private static final int KEEP_ALIVE = 1;
36 
37     /**
38      * An {@link ThreadPoolExecutor} to be used with async task with no limit on the queue size.
39      */
40     public static final ThreadPoolExecutor THREAD_POOL_EXECUTOR = new ThreadPoolExecutor(
41             CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE,
42             TimeUnit.SECONDS, new LinkedBlockingQueue<>());
43 
44     /**
45      * Returns the executor for running tasks on the main thread.
46      */
47     public static final LooperExecutor MAIN_EXECUTOR =
48             new LooperExecutor(Looper.getMainLooper());
49 
50     /**
51      * A background executor for using time sensitive actions where user is waiting for response.
52      */
53     public static final LooperExecutor UI_HELPER_EXECUTOR =
54             new LooperExecutor(createAndStartNewForegroundLooper("UiThreadHelper"));
55 
56     /**
57      * Utility method to get a started handler thread statically
58      */
createAndStartNewLooper(String name)59     public static Looper createAndStartNewLooper(String name) {
60         return createAndStartNewLooper(name, Process.THREAD_PRIORITY_DEFAULT);
61     }
62 
63     /**
64      * Utility method to get a started handler thread statically with the provided priority
65      */
createAndStartNewLooper(String name, int priority)66     public static Looper createAndStartNewLooper(String name, int priority) {
67         HandlerThread thread = new HandlerThread(name, priority);
68         thread.start();
69         return thread.getLooper();
70     }
71 
72     /**
73      * Similar to {@link #createAndStartNewLooper(String)}, but starts the thread with
74      * foreground priority.
75      * Think before using
76      */
createAndStartNewForegroundLooper(String name)77     public static Looper createAndStartNewForegroundLooper(String name) {
78         return createAndStartNewLooper(name, Process.THREAD_PRIORITY_FOREGROUND);
79     }
80 
81     /**
82      * Executor used for running Launcher model related tasks (eg loading icons or updated db)
83      */
84     public static final LooperExecutor MODEL_EXECUTOR =
85             new LooperExecutor(createAndStartNewLooper("launcher-loader"));
86 }
87