1/*
2 * Copyright (C) 2013 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
17package com.android.internal.os;
18
19import android.os.Handler;
20import android.os.HandlerThread;
21import android.os.Trace;
22
23/**
24 * Shared singleton background thread for each process.
25 */
26public final class BackgroundThread extends HandlerThread {
27    private static BackgroundThread sInstance;
28    private static Handler sHandler;
29
30    private BackgroundThread() {
31        super("android.bg", android.os.Process.THREAD_PRIORITY_BACKGROUND);
32    }
33
34    private static void ensureThreadLocked() {
35        if (sInstance == null) {
36            sInstance = new BackgroundThread();
37            sInstance.start();
38            sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_ACTIVITY_MANAGER);
39            sHandler = new Handler(sInstance.getLooper());
40        }
41    }
42
43    public static BackgroundThread get() {
44        synchronized (BackgroundThread.class) {
45            ensureThreadLocked();
46            return sInstance;
47        }
48    }
49
50    public static Handler getHandler() {
51        synchronized (BackgroundThread.class) {
52            ensureThreadLocked();
53            return sHandler;
54        }
55    }
56}
57