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.dialer.common.concurrent;
17 
18 import com.google.common.util.concurrent.AbstractListeningExecutorService;
19 import com.google.common.util.concurrent.ListenableFuture;
20 import com.google.common.util.concurrent.SettableFuture;
21 import java.util.List;
22 import java.util.concurrent.Callable;
23 import java.util.concurrent.TimeUnit;
24 import javax.inject.Inject;
25 
26 /**
27  * An ExecutorService that delegates to the UI thread. Rejects attempts to shut down, and all
28  * shutdown related APIs are unimplemented.
29  *
30  */
31 public class UiThreadExecutor extends AbstractListeningExecutorService {
32 
33   @Inject
UiThreadExecutor()34   public UiThreadExecutor() {}
35 
36   @Override
shutdown()37   public void shutdown() {
38     throw new UnsupportedOperationException();
39   }
40 
41   @Override
shutdownNow()42   public List<Runnable> shutdownNow() {
43     throw new UnsupportedOperationException();
44   }
45 
46   @Override
isShutdown()47   public boolean isShutdown() {
48     return false;
49   }
50 
51   @Override
isTerminated()52   public boolean isTerminated() {
53     return false;
54   }
55 
56   @Override
awaitTermination(long l, TimeUnit timeUnit)57   public boolean awaitTermination(long l, TimeUnit timeUnit) throws InterruptedException {
58     throw new UnsupportedOperationException();
59   }
60 
61   @Override
submit(final Callable<V> task)62   public <V> ListenableFuture<V> submit(final Callable<V> task) {
63     final SettableFuture<V> resultFuture = SettableFuture.create();
64     ThreadUtil.postOnUiThread(
65         () -> {
66           try {
67             resultFuture.set(task.call());
68           } catch (Exception e) {
69             // uncaught exceptions on the UI thread should crash the app
70             resultFuture.setException(e);
71             throw new RuntimeException(e);
72           }
73         });
74     return resultFuture;
75   }
76 
77   @Override
execute(final Runnable runnable)78   public void execute(final Runnable runnable) {
79     ThreadUtil.postOnUiThread(runnable);
80   }
81 }
82