SuperstepKickoffLatchTest.java

/*
 * 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.flink.runtime.iterative.concurrent;

import org.junit.Assert;
import org.junit.Test;

public class SuperstepKickoffLatchTest {

	@Test
	public void testWaitFromOne() {
		try {
			SuperstepKickoffLatch latch = new SuperstepKickoffLatch();
			
			Waiter w = new Waiter(latch, 2);
			Thread waiter = new Thread(w);
			waiter.setDaemon(true);
			waiter.start();
			
			WatchDog wd = new WatchDog(waiter, 2000);
			wd.start();
			
			Thread.sleep(100);
			
			latch.triggerNextSuperstep();
			
			wd.join();
			if (wd.getError() != null) {
				throw wd.getError();
			}
			
			if (w.getError() != null) {
				throw w.getError();
			}
		}
		catch (Throwable t) {
			t.printStackTrace();
			Assert.fail("Error: " + t.getMessage());
		}
	}
	
	@Test
	public void testWaitAlreadyFulfilled() {
		try {
			SuperstepKickoffLatch latch = new SuperstepKickoffLatch();
			latch.triggerNextSuperstep();
			
			Waiter w = new Waiter(latch, 2);
			Thread waiter = new Thread(w);
			waiter.setDaemon(true);
			waiter.start();
			
			WatchDog wd = new WatchDog(waiter, 2000);
			wd.start();
			
			Thread.sleep(100);
			
			wd.join();
			if (wd.getError() != null) {
				throw wd.getError();
			}
			
			if (w.getError() != null) {
				throw w.getError();
			}
		}
		catch (Throwable t) {
			t.printStackTrace();
			Assert.fail("Error: " + t.getMessage());
		}
	}
	
	@Test
	public void testWaitIncorrect() {
		try {
			SuperstepKickoffLatch latch = new SuperstepKickoffLatch();
			latch.triggerNextSuperstep();
			latch.triggerNextSuperstep();
			
			try {
				latch.awaitStartOfSuperstepOrTermination(2);
				Assert.fail("should throw exception");
			}
			catch (IllegalStateException e) {
				// good
			}
		}
		catch (Exception e) {
			e.printStackTrace();
			Assert.fail("Error: " + e.getMessage());
		}
	}
	
	@Test
	public void testWaitIncorrectAsync() {
		try {
			SuperstepKickoffLatch latch = new SuperstepKickoffLatch();
			latch.triggerNextSuperstep();
			latch.triggerNextSuperstep();
			
			Waiter w = new Waiter(latch, 2);
			Thread waiter = new Thread(w);
			waiter.setDaemon(true);
			waiter.start();
			
			WatchDog wd = new WatchDog(waiter, 2000);
			wd.start();
			
			Thread.sleep(100);
			
			wd.join();
			if (wd.getError() != null) {
				throw wd.getError();
			}
			
			if (w.getError() != null) {
				if (!(w.getError() instanceof IllegalStateException)) {
					throw new Exception("wrong exception type " + w.getError());
				}
			} else {
				Assert.fail("should cause exception");
			}
		}
		catch (Throwable t) {
			t.printStackTrace();
			Assert.fail("Error: " + t.getMessage());
		}
	}
	
	@Test
	public void testWaitForTermination() {
		try {
			SuperstepKickoffLatch latch = new SuperstepKickoffLatch();
			latch.triggerNextSuperstep();
			latch.triggerNextSuperstep();
			
			Waiter w = new Waiter(latch, 4);
			Thread waiter = new Thread(w);
			waiter.setDaemon(true);
			waiter.start();
			
			WatchDog wd = new WatchDog(waiter, 2000);
			wd.start();
			
			latch.signalTermination();
			
			wd.join();
			if (wd.getError() != null) {
				throw wd.getError();
			}
			
			if (w.getError() != null) {
				throw w.getError();
			}
		}
		catch (Throwable t) {
			t.printStackTrace();
			Assert.fail("Error: " + t.getMessage());
		}
	}
	
	private static class Waiter implements Runnable {

		private final SuperstepKickoffLatch latch;
		
		private final int waitFor;
		
		private volatile Throwable error;
		
		
		public Waiter(SuperstepKickoffLatch latch, int waitFor) {
			this.latch = latch;
			this.waitFor = waitFor;
		}

		@Override
		public void run() {
			try {
				latch.awaitStartOfSuperstepOrTermination(waitFor);
			}
			catch (Throwable t) {
				this.error = t;
			}
		}
		
		public Throwable getError() {
			return error;
		}
	}
	
	private static class WatchDog extends Thread {
		
		private final Thread toWatch;
		
		private final long timeOut;
		
		private volatile Throwable failed;
		
		public WatchDog(Thread toWatch, long timeout) {
			setDaemon(true);
			setName("Watchdog");
			this.toWatch = toWatch;
			this.timeOut = timeout;
		}
		
		@SuppressWarnings("deprecation")
		@Override
		public void run() {
			try {
				toWatch.join(timeOut);
				
				if (toWatch.isAlive()) {
					this.failed = new Exception("timed out");
					toWatch.interrupt();
					
					toWatch.join(2000);
					if (toWatch.isAlive()) {
						toWatch.stop();
					}
				}
			}
			catch (Throwable t) {
				failed = t;
			}
		}
		
		public Throwable getError() {
			return failed;
		}
	}
}