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.Executor;
23 import java.util.concurrent.LinkedBlockingQueue;
24 import java.util.concurrent.ThreadPoolExecutor;
25 import java.util.concurrent.TimeUnit;
26 
27 /**
28  * Various different executors used in Launcher
29  */
30 public class Executors {
31 
32     // These values are same as that in {@link AsyncTask}.
33     private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();
34     private static final int CORE_POOL_SIZE = CPU_COUNT + 1;
35     private static final int MAXIMUM_POOL_SIZE = CPU_COUNT * 2 + 1;
36     private static final int KEEP_ALIVE = 1;
37 
38     /**
39      * An {@link Executor} to be used with async task with no limit on the queue size.
40      */
41     public static final Executor THREAD_POOL_EXECUTOR = new ThreadPoolExecutor(
42             CORE_POOL_SIZE, MAXIMUM_POOL_SIZE, KEEP_ALIVE,
43             TimeUnit.SECONDS, new LinkedBlockingQueue<>());
44 
45     /**
46      * Returns the executor for running tasks on the main thread.
47      */
48     public static final LooperExecutor MAIN_EXECUTOR =
49             new LooperExecutor(Looper.getMainLooper());
50 
51     /**
52      * A background executor for using time sensitive actions where user is waiting for response.
53      */
54     public static final LooperExecutor UI_HELPER_EXECUTOR =
55             new LooperExecutor(createAndStartNewForegroundLooper("UiThreadHelper"));
56 
57     /**
58      * Utility method to get a started handler thread statically
59      */
createAndStartNewLooper(String name)60     public static Looper createAndStartNewLooper(String name) {
61         return createAndStartNewLooper(name, Process.THREAD_PRIORITY_DEFAULT);
62     }
63 
64     /**
65      * Utility method to get a started handler thread statically with the provided priority
66      */
createAndStartNewLooper(String name, int priority)67     public static Looper createAndStartNewLooper(String name, int priority) {
68         HandlerThread thread = new HandlerThread(name, priority);
69         thread.start();
70         return thread.getLooper();
71     }
72 
73     /**
74      * Similar to {@link #createAndStartNewLooper(String)}, but starts the thread with
75      * foreground priority.
76      * Think before using
77      */
createAndStartNewForegroundLooper(String name)78     public static Looper createAndStartNewForegroundLooper(String name) {
79         return createAndStartNewLooper(name, Process.THREAD_PRIORITY_FOREGROUND);
80     }
81 
82     /**
83      * Executor used for running Launcher model related tasks (eg loading icons or updated db)
84      */
85     public static final LooperExecutor MODEL_EXECUTOR =
86             new LooperExecutor(createAndStartNewLooper("launcher-loader"));
87 }
88