1 /*
2  * Copyright (C) 2016 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 android.net;
18 
19 import android.os.HandlerThread;
20 import android.os.Looper;
21 
22 /**
23  * Shared singleton connectivity thread for the system.  This is a thread for
24  * connectivity operations such as AsyncChannel connections to system services.
25  * Various connectivity manager objects can use this singleton as a common
26  * resource for their handlers instead of creating separate threads of their own.
27  * @hide
28  */
29 public final class ConnectivityThread extends HandlerThread {
30 
31     // A class implementing the lazy holder idiom: the unique static instance
32     // of ConnectivityThread is instantiated in a thread-safe way (guaranteed by
33     // the language specs) the first time that Singleton is referenced in get()
34     // or getInstanceLooper().
35     private static class Singleton {
36         private static final ConnectivityThread INSTANCE = createInstance();
37     }
38 
ConnectivityThread()39     private ConnectivityThread() {
40         super("ConnectivityThread");
41     }
42 
createInstance()43     private static ConnectivityThread createInstance() {
44         ConnectivityThread t = new ConnectivityThread();
45         t.start();
46         return t;
47     }
48 
get()49     public static ConnectivityThread get() {
50         return Singleton.INSTANCE;
51     }
52 
getInstanceLooper()53     public static Looper getInstanceLooper() {
54         return Singleton.INSTANCE.getLooper();
55     }
56 }
57