/**
* Licensed to The Apereo Foundation under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
*
*
* The Apereo Foundation licenses this file to you under the Educational
* Community 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://opensource.org/licenses/ecl2.txt
*
* 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.opencastproject.oaipmh.util;
import org.opencastproject.util.data.Function0;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;
/**
* Functions dealing with concurrency.
*/
public final class ConcurrencyUtil {
private ConcurrencyUtil() {
}
/**
* Gently shut down an executor service. Waits for <code>waitSeconds</code> then tries
* to forcibly terminate the service. Waits again then calls <code>executorDoesNotTerminate</code>.
*/
public static void shutdownAndAwaitTermination(ExecutorService exe, int waitSeconds,
Function0<Void> executorDoesNotTerminate) {
// Disable new tasks from being submitted
exe.shutdown();
try {
// Wait a while for existing tasks to terminate
if (!exe.awaitTermination(waitSeconds, TimeUnit.SECONDS)) {
// Cancel currently executing tasks
exe.shutdownNow();
// Wait a while for tasks to respond to being cancelled
if (!exe.awaitTermination(waitSeconds, TimeUnit.SECONDS))
executorDoesNotTerminate.apply();
}
} catch (InterruptedException ie) {
// Forcibly terminate on interruption
exe.shutdownNow();
// Preserve interrupt status
Thread.currentThread().interrupt();
}
}
}