| /* |
| * Copyright (C) 2007 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.server; |
| |
| import android.os.SystemClock; |
| |
| import android.os.ConditionVariable; |
| |
| /** |
| * Utility class that you can call on with a timeout, and get called back |
| * after a given time, dealing correctly with restarting the timeout. |
| * |
| * <p>For example, this class is used by the android.os.Vibrator class. |
| */ |
| abstract class ResettableTimeout |
| { |
| /** |
| * Override this do what you need to do when it's starting |
| * This is called with the monitor on this method held, so be careful. |
| * |
| * @param alreadyOn is true if it's currently running |
| */ |
| public abstract void on(boolean alreadyOn); |
| |
| /** |
| * Override this to do what you need to do when it's stopping. |
| * This is called with the monitor on this method held, so be careful. |
| */ |
| public abstract void off(); |
| |
| /** |
| * Does the following steps. |
| * <p>1. Call on()</p> |
| * <p>2. Start the timer.</p> |
| * <p>3. At the timeout, calls off()<p> |
| * <p>If you call this again, the timeout is reset to the new one</p> |
| */ |
| public void go(long milliseconds) |
| { |
| synchronized (this) { |
| mOffAt = SystemClock.uptimeMillis() + milliseconds; |
| |
| boolean alreadyOn; |
| |
| // By starting the thread first and waiting, we ensure that if the |
| // thread to stop it can't start, we don't turn the vibrator on |
| // forever. This still isn't really sufficient, because we don't |
| // have another processor watching us. We really should have a |
| // service for this in case our process crashes. |
| if (mThread == null) { |
| alreadyOn = false; |
| mLock.close(); |
| mThread = new T(); |
| mThread.start(); |
| mLock.block(); |
| mOffCalled = false; |
| } else { |
| alreadyOn = true; |
| // poke the thread so it gets the new timeout. |
| mThread.interrupt(); |
| } |
| on(alreadyOn); |
| } |
| } |
| |
| /** |
| * Cancel the timeout and call off now. |
| */ |
| public void cancel() |
| { |
| synchronized (this) { |
| mOffAt = 0; |
| if (mThread != null) { |
| mThread.interrupt(); |
| mThread = null; |
| } |
| if (!mOffCalled) { |
| mOffCalled = true; |
| off(); |
| } |
| } |
| } |
| |
| private class T extends Thread |
| { |
| public void run() |
| { |
| mLock.open(); |
| while (true) { |
| long diff; |
| synchronized (this) { |
| diff = mOffAt - SystemClock.uptimeMillis(); |
| if (diff <= 0) { |
| mOffCalled = true; |
| off(); |
| mThread = null; |
| break; |
| } |
| } |
| try { |
| sleep(diff); |
| } |
| catch (InterruptedException e) { |
| } |
| } |
| } |
| } |
| |
| private ConditionVariable mLock = new ConditionVariable(); |
| |
| // turn it off at this time. |
| private volatile long mOffAt; |
| private volatile boolean mOffCalled; |
| |
| private Thread mThread; |
| |
| } |
| |