| /* |
| * Copyright (C) 2014 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.camera.async; |
| |
| import java.util.concurrent.Executor; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.ScheduledFuture; |
| import java.util.concurrent.TimeUnit; |
| |
| /** |
| * An executor which executes with a delay, discarding pending executions such |
| * that at most one task is queued at any time. |
| */ |
| public class ResettingDelayedExecutor implements Executor, SafeCloseable { |
| private final ScheduledExecutorService mExecutor; |
| private final long mDelay; |
| private final TimeUnit mDelayUnit; |
| /** |
| * Lock for all mutable state: {@link #mLatestRunRequest} and |
| * {@link #mClosed}. |
| */ |
| private final Object mLock; |
| private ScheduledFuture<?> mLatestRunRequest; |
| private boolean mClosed; |
| |
| public ResettingDelayedExecutor(ScheduledExecutorService executor, long delay, TimeUnit |
| delayUnit) { |
| mExecutor = executor; |
| mDelay = delay; |
| mDelayUnit = delayUnit; |
| mLock = new Object(); |
| } |
| |
| @Override |
| public void execute(Runnable runnable) { |
| synchronized (mLock) { |
| if (mClosed) { |
| return; |
| } |
| // Cancel any existing, queued task before scheduling another. |
| if (mLatestRunRequest != null) { |
| boolean mayInterruptIfRunning = false; |
| mLatestRunRequest.cancel(mayInterruptIfRunning); |
| } |
| mLatestRunRequest = mExecutor.schedule(runnable, mDelay, mDelayUnit); |
| } |
| } |
| |
| @Override |
| public void close() { |
| synchronized (mLock) { |
| if (mClosed) { |
| return; |
| } |
| mExecutor.shutdownNow(); |
| } |
| } |
| } |