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 package com.android.launcher3.util;
17 
18 import android.os.Handler;
19 import android.os.HandlerThread;
20 import android.os.Looper;
21 import android.os.Process;
22 
23 import java.util.List;
24 import java.util.concurrent.AbstractExecutorService;
25 import java.util.concurrent.TimeUnit;
26 
27 /**
28  * Extension of {@link AbstractExecutorService} which executed on a provided looper.
29  */
30 public class LooperExecutor extends AbstractExecutorService {
31 
32     private final Handler mHandler;
33 
LooperExecutor(Looper looper)34     public LooperExecutor(Looper looper) {
35         mHandler = new Handler(looper);
36     }
37 
getHandler()38     public Handler getHandler() {
39         return mHandler;
40     }
41 
42     @Override
execute(Runnable runnable)43     public void execute(Runnable runnable) {
44         if (mHandler.getLooper() == Looper.myLooper()) {
45             runnable.run();
46         } else {
47             mHandler.post(runnable);
48         }
49     }
50 
51     /**
52      * Same as execute, but never runs the action inline.
53      */
post(Runnable runnable)54     public void post(Runnable runnable) {
55         mHandler.post(runnable);
56     }
57 
58     /**
59      * Not supported and throws an exception when used.
60      */
61     @Override
62     @Deprecated
shutdown()63     public void shutdown() {
64         throw new UnsupportedOperationException();
65     }
66 
67     /**
68      * Not supported and throws an exception when used.
69      */
70     @Override
71     @Deprecated
shutdownNow()72     public List<Runnable> shutdownNow() {
73         throw new UnsupportedOperationException();
74     }
75 
76     @Override
isShutdown()77     public boolean isShutdown() {
78         return false;
79     }
80 
81     @Override
isTerminated()82     public boolean isTerminated() {
83         return false;
84     }
85 
86     /**
87      * Not supported and throws an exception when used.
88      */
89     @Override
90     @Deprecated
awaitTermination(long l, TimeUnit timeUnit)91     public boolean awaitTermination(long l, TimeUnit timeUnit) {
92         throw new UnsupportedOperationException();
93     }
94 
95     /**
96      * Returns the thread for this executor
97      */
getThread()98     public Thread getThread() {
99         return mHandler.getLooper().getThread();
100     }
101 
102     /**
103      * Returns the looper for this executor
104      */
getLooper()105     public Looper getLooper() {
106         return mHandler.getLooper();
107     }
108 
109     /**
110      * Set the priority of a thread, based on Linux priorities.
111      * @param priority Linux priority level, from -20 for highest scheduling priority
112      *                to 19 for lowest scheduling priority.
113      * @see Process#setThreadPriority(int, int)
114      */
setThreadPriority(int priority)115     public void setThreadPriority(int priority) {
116         Process.setThreadPriority(((HandlerThread) getThread()).getThreadId(), priority);
117     }
118 }
119