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 
17 package com.android.systemui.shared.system;
18 
19 import java.util.concurrent.Callable;
20 import java.util.concurrent.ExecutorService;
21 import java.util.concurrent.Executors;
22 import java.util.concurrent.Future;
23 
24 /**
25  * Offloads work from other threads by running it in a background thread.
26  */
27 public class BackgroundExecutor {
28 
29     private static final BackgroundExecutor sInstance = new BackgroundExecutor();
30 
31     private final ExecutorService mExecutorService = Executors.newFixedThreadPool(2);
32 
33     /**
34      * @return the static instance of the background executor.
35      */
get()36     public static BackgroundExecutor get() {
37         return sInstance;
38     }
39 
40     /**
41      * Runs the given {@param callable} on one of the background executor threads.
42      */
submit(Callable<T> callable)43     public <T> Future<T> submit(Callable<T> callable) {
44         return mExecutorService.submit(callable);
45     }
46 
47     /**
48      * Runs the given {@param runnable} on one of the background executor threads.
49      */
submit(Runnable runnable)50     public Future<?> submit(Runnable runnable) {
51         return mExecutorService.submit(runnable);
52     }
53 
54     /**
55      * Runs the given {@param runnable} on one of the background executor threads. Return
56      * {@param result} when the future is resolved.
57      */
submit(Runnable runnable, T result)58     public <T> Future<T> submit(Runnable runnable, T result) {
59         return mExecutorService.submit(runnable, result);
60     }
61 }
62