| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.beam.sdk.testing; |
| |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.locks.LockSupport; |
| import org.apache.beam.sdk.util.Sleeper; |
| |
| /** |
| * This class provides an expensive sleeper to deal with issues around Java's accuracy of {@link |
| * System#currentTimeMillis} and methods such as {@link Object#wait} and {@link Thread#sleep} which |
| * depend on it. This <a href="https://blogs.oracle.com/dholmes/entry/inside_the_hotspot_vm_clocks"> |
| * article</a> goes into further detail about this issue. |
| * |
| * <p>This {@link Sleeper} uses {@link System#nanoTime} as the timing source and {@link |
| * LockSupport#parkNanos} as the wait method. Note that usage of this sleeper may impact performance |
| * because of the relatively more expensive methods being invoked when compared to {@link |
| * Thread#sleep}. |
| */ |
| public class SystemNanoTimeSleeper implements Sleeper { |
| public static final Sleeper INSTANCE = new SystemNanoTimeSleeper(); |
| |
| /** Limit visibility to prevent instantiation. */ |
| private SystemNanoTimeSleeper() {} |
| |
| @Override |
| public void sleep(long millis) throws InterruptedException { |
| long currentTime; |
| long endTime = System.nanoTime() + TimeUnit.NANOSECONDS.convert(millis, TimeUnit.MILLISECONDS); |
| while ((currentTime = System.nanoTime()) < endTime) { |
| if (Thread.interrupted()) { |
| throw new InterruptedException(); |
| } |
| LockSupport.parkNanos(endTime - currentTime); |
| } |
| if (Thread.interrupted()) { |
| throw new InterruptedException(); |
| } |
| } |
| |
| /** |
| * Causes the currently executing thread to sleep (temporarily cease execution) for the specified |
| * number of milliseconds. The thread does not lose ownership of any monitors. |
| */ |
| public static void sleepMillis(long millis) throws InterruptedException { |
| INSTANCE.sleep(millis); |
| } |
| } |