1 /* 2 * Copyright (C) 2015 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.internal.util; 18 19 import android.app.AlarmManager; 20 import android.content.Context; 21 import android.os.Handler; 22 import android.os.Message; 23 24 import com.android.internal.annotations.VisibleForTesting; 25 26 /** 27 * An AlarmListener that sends the specified message to a Handler and keeps the system awake until 28 * the message is processed. 29 * 30 * This is useful when using the AlarmManager direct callback interface to wake up the system and 31 * request that an object whose API consists of messages (such as a StateMachine) perform some 32 * action. 33 * 34 * In this situation, using AlarmManager.onAlarmListener by itself will wake up the system to send 35 * the message, but does not guarantee that the system will be awake until the target object has 36 * processed it. This is because as soon as the onAlarmListener sends the message and returns, the 37 * AlarmManager releases its wakelock and the system is free to go to sleep again. 38 */ 39 public class WakeupMessage implements AlarmManager.OnAlarmListener { 40 private final AlarmManager mAlarmManager; 41 42 @VisibleForTesting 43 protected final Handler mHandler; 44 @VisibleForTesting 45 protected final String mCmdName; 46 @VisibleForTesting 47 protected final int mCmd, mArg1, mArg2; 48 @VisibleForTesting 49 protected final Object mObj; 50 private boolean mScheduled; 51 WakeupMessage(Context context, Handler handler, String cmdName, int cmd, int arg1, int arg2, Object obj)52 public WakeupMessage(Context context, Handler handler, 53 String cmdName, int cmd, int arg1, int arg2, Object obj) { 54 mAlarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE); 55 mHandler = handler; 56 mCmdName = cmdName; 57 mCmd = cmd; 58 mArg1 = arg1; 59 mArg2 = arg2; 60 mObj = obj; 61 } 62 WakeupMessage(Context context, Handler handler, String cmdName, int cmd, int arg1)63 public WakeupMessage(Context context, Handler handler, String cmdName, int cmd, int arg1) { 64 this(context, handler, cmdName, cmd, arg1, 0, null); 65 } 66 WakeupMessage(Context context, Handler handler, String cmdName, int cmd, int arg1, int arg2)67 public WakeupMessage(Context context, Handler handler, 68 String cmdName, int cmd, int arg1, int arg2) { 69 this(context, handler, cmdName, cmd, arg1, arg2, null); 70 } 71 WakeupMessage(Context context, Handler handler, String cmdName, int cmd)72 public WakeupMessage(Context context, Handler handler, String cmdName, int cmd) { 73 this(context, handler, cmdName, cmd, 0, 0, null); 74 } 75 76 /** 77 * Schedule the message to be delivered at the time in milliseconds of the 78 * {@link android.os.SystemClock#elapsedRealtime SystemClock.elapsedRealtime()} clock and wakeup 79 * the device when it goes off. If schedule is called multiple times without the message being 80 * dispatched then the alarm is rescheduled to the new time. 81 */ schedule(long when)82 public synchronized void schedule(long when) { 83 mAlarmManager.setExact( 84 AlarmManager.ELAPSED_REALTIME_WAKEUP, when, mCmdName, this, mHandler); 85 mScheduled = true; 86 } 87 88 /** 89 * Cancel all pending messages. This includes alarms that may have been fired, but have not been 90 * run on the handler yet. 91 */ cancel()92 public synchronized void cancel() { 93 if (mScheduled) { 94 mAlarmManager.cancel(this); 95 mScheduled = false; 96 } 97 } 98 99 @Override onAlarm()100 public void onAlarm() { 101 // Once this method is called the alarm has already been fired and removed from 102 // AlarmManager (it is still partially tracked, but only for statistics). The alarm can now 103 // be marked as unscheduled so that it can be rescheduled in the message handler. 104 final boolean stillScheduled; 105 synchronized (this) { 106 stillScheduled = mScheduled; 107 mScheduled = false; 108 } 109 if (stillScheduled) { 110 Message msg = mHandler.obtainMessage(mCmd, mArg1, mArg2, mObj); 111 mHandler.handleMessage(msg); 112 msg.recycle(); 113 } 114 } 115 } 116