/*
* Copyright (c) 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 David Berkman
*
* This file is part of the SmallMind Code Project.
*
* The SmallMind Code Project is free software, you can redistribute
* it and/or modify it under either, at your discretion...
*
* 1) The terms of GNU Affero General Public License as published by the
* Free Software Foundation, either version 3 of the License, or (at
* your option) any later version.
*
* ...or...
*
* 2) The terms of the Apache License, Version 2.0.
*
* The SmallMind Code Project is distributed in the hope that it will
* be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License or Apache License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* and the Apache License along with the SmallMind Code Project. If not, see
* <http://www.gnu.org/licenses/> or <http://www.apache.org/licenses/LICENSE-2.0>.
*
* Additional permission under the GNU Affero GPL version 3 section 7
* ------------------------------------------------------------------
* If you modify this Program, or any covered work, by linking or
* combining it with other code, such other code is not for that reason
* alone subject to any of the requirements of the GNU Affero GPL
* version 3.
*/
package org.smallmind.nutsnbolts.util;
import java.util.NavigableSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentSkipListSet;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import org.smallmind.nutsnbolts.time.Duration;
public class SelfDestructiveMap<K extends Comparable<K>, S extends SelfDestructive> {
private final ConcurrentHashMap<K, S> internalMap = new ConcurrentHashMap<K, S>();
private final ConcurrentSkipListSet<SelfDestructiveKey<K>> ignitionKeySet = new ConcurrentSkipListSet<>();
private final Duration defaultTimeoutDuration;
private final Duration pulseTimeDuration;
private IgnitionWorker ignitionWorker;
public SelfDestructiveMap (Duration defaultTimeoutDuration) {
this(defaultTimeoutDuration, new Duration(1, TimeUnit.SECONDS));
}
public SelfDestructiveMap (Duration defaultTimeoutDuration, Duration pulseTimeDuration) {
Thread ignitionThread;
this.defaultTimeoutDuration = defaultTimeoutDuration;
this.pulseTimeDuration = pulseTimeDuration;
ignitionThread = new Thread(ignitionWorker = new IgnitionWorker());
ignitionThread.setDaemon(true);
ignitionThread.start();
}
public S get (K key) {
return internalMap.get(key);
}
public S putIfAbsent (K key, S value) {
return putIfAbsent(key, value, defaultTimeoutDuration);
}
public S putIfAbsent (K key, S value, Duration timeoutDuration) {
S previousValue;
if ((previousValue = internalMap.putIfAbsent(key, value)) == null) {
ignitionKeySet.add(new SelfDestructiveKey<>(key, (timeoutDuration != null) ? timeoutDuration : defaultTimeoutDuration));
}
return previousValue;
}
public void shutdown ()
throws InterruptedException {
ignitionWorker.shutdown();
}
@Override
protected void finalize ()
throws InterruptedException {
shutdown();
}
private class IgnitionWorker implements Runnable {
private final CountDownLatch terminationLatch = new CountDownLatch(1);
private final CountDownLatch exitLatch = new CountDownLatch(1);
public void shutdown ()
throws InterruptedException {
terminationLatch.countDown();
exitLatch.await();
}
@Override
public void run () {
try {
while (!terminationLatch.await(pulseTimeDuration.getTime(), pulseTimeDuration.getTimeUnit())) {
NavigableSet<SelfDestructiveKey<K>> ignitedKeySet;
if (!(ignitedKeySet = ignitionKeySet.headSet(new SelfDestructiveKey<K>(Duration.none()))).isEmpty()) {
SelfDestructiveKey<K> ignitedKey;
while ((ignitedKey = ignitedKeySet.pollFirst()) != null) {
SelfDestructive selfDestructive;
if ((selfDestructive = internalMap.remove(ignitedKey.getMapKey())) != null) {
selfDestructive.destroy(ignitedKey.getTimeoutDuration());
}
}
}
}
} catch (InterruptedException interruptedException) {
terminationLatch.countDown();
}
exitLatch.countDown();
}
}
}