/**
* Copyright 2014 Netflix, Inc.
*
* 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 rx.test;
import java.util.*;
import java.util.concurrent.*;
import rx.Scheduler;
import rx.functions.Action0;
import rx.schedulers.Schedulers;
/**
* Check if there is an obstruction in the computation scheduler.
* Put the following code into test classes:
* <code><pre>
* @org.junit.After
* public void doAfterTest() {
* rx.test.TestObstructionDetection.checkObstruction();
* }
* </pre></code>
* or
* <pre><code>
* @org.junit.AfterClass
* public static void doAfterClass() {
* rx.test.TestObstructionDetection.checkObstruction();
* }
* </code></pre>
*/
public final class TestObstructionDetection {
private TestObstructionDetection() {
throw new IllegalStateException("No instances!");
}
/**
* Checks if tasks can be immediately executed on the computation scheduler.
* @throws ObstructionExceptio if the schedulers don't respond within 1 second
*/
public static void checkObstruction() {
final int ncpu = Runtime.getRuntime().availableProcessors();
final CountDownLatch cdl = new CountDownLatch(ncpu);
final List<Scheduler.Worker> workers = new ArrayList<Scheduler.Worker>();
final Action0 task = new Action0() {
@Override
public void call() {
cdl.countDown();
}
};
for (int i = 0; i < ncpu; i++) {
workers.add(Schedulers.computation().createWorker());
}
for (Scheduler.Worker w : workers) {
w.schedule(task);
}
try {
if (!cdl.await(1, TimeUnit.SECONDS)) {
throw new ObstructionException("Obstruction/Timeout detected!");
}
} catch (InterruptedException ex) {
throw new ObstructionException("Interrupted: " + ex);
} finally {
for (Scheduler.Worker w : workers) {
w.unsubscribe();
}
}
}
/**
* Exception thrown if obstruction was detected.
*/
public static final class ObstructionException extends RuntimeException {
/** */
private static final long serialVersionUID = -6380717994471291795L;
public ObstructionException(String message) {
super(message);
}
}
}