/*
* JBoss, Home of Professional Open Source.
* Copyright 2013, Red Hat, Inc., and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.as.ejb3.cache.simple;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import org.jboss.as.ejb3.cache.Cache;
import org.jboss.as.ejb3.cache.Identifiable;
import org.jboss.as.ejb3.cache.StatefulObjectFactory;
import org.jboss.as.ejb3.component.stateful.StatefulTimeoutInfo;
import org.jboss.as.ejb3.logging.EjbLogger;
import org.jboss.as.server.ServerEnvironment;
import org.jboss.ejb.client.Affinity;
import org.jboss.ejb.client.NodeAffinity;
import org.wildfly.clustering.ejb.IdentifierFactory;
/**
* Simple {@link Cache} implementation using in-memory storage and eager expiration.
*
* @author Paul Ferraro
*
* @param <K> the cache key type
* @param <V> the cache value type
*/
public class SimpleCache<K, V extends Identifiable<K>> implements Cache<K, V> {
final Map<K, Future<?>> expirationFutures = new ConcurrentHashMap<>();
private final ConcurrentMap<K, Entry<V>> entries = new ConcurrentHashMap<>();
private final StatefulObjectFactory<V> factory;
private final IdentifierFactory<K> identifierFactory;
private final StatefulTimeoutInfo timeout;
private final ServerEnvironment environment;
private final ScheduledExecutorService executor;
public SimpleCache(StatefulObjectFactory<V> factory, IdentifierFactory<K> identifierFactory, StatefulTimeoutInfo timeout, ServerEnvironment environment, ScheduledExecutorService executor) {
this.factory = factory;
this.identifierFactory = identifierFactory;
this.timeout = timeout;
this.environment = environment;
this.executor = executor;
}
@Override
public void start() {
// Do nothing
}
@Override
public void stop() {
for (Future<?> future: this.expirationFutures.values()) {
future.cancel(true);
}
for (Future<?> future: this.expirationFutures.values()) {
if (!future.isCancelled() && !future.isDone()) {
try {
future.get();
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
} catch (ExecutionException e) {
// Ignore
}
}
}
for(Map.Entry<K, Entry<V>> entry : entries.entrySet()) {
this.factory.destroyInstance(entry.getValue().getValue());
}
this.expirationFutures.clear();
this.entries.clear();
}
@Override
public Affinity getStrictAffinity() {
return new NodeAffinity(this.environment.getNodeName());
}
@Override
public Affinity getWeakAffinity(K key) {
return Affinity.NONE;
}
@Override
public K createIdentifier() {
return this.identifierFactory.createIdentifier();
}
@Override
public V create() {
if (CURRENT_GROUP.get() != null) {
// An SFSB that uses a distributable cache cannot contain an SFSB that uses a simple cache
throw EjbLogger.ROOT_LOGGER.incompatibleCaches();
}
V bean = this.factory.createInstance();
this.entries.put(bean.getId(), new Entry<>(bean));
return bean;
}
@Override
public void discard(V value) {
this.entries.remove(value.getId());
}
@Override
public void remove(K key) {
Entry<V> entry = this.entries.remove(key);
if (entry != null) {
this.factory.destroyInstance(entry.getValue());
}
}
@Override
public V get(K key) {
Future<?> future = this.expirationFutures.get(key);
if (future != null) {
future.cancel(true);
}
Entry<V> entry = this.entries.get(key);
if (entry == null) return null;
entry.use();
return entry.getValue();
}
@Override
public boolean contains(K key) {
return this.entries.containsKey(key);
}
@Override
public void release(V bean) {
K id = bean.getId();
Entry<V> entry = this.entries.get(id);
if ((entry != null) && entry.done()) {
if (this.timeout != null) {
long value = this.timeout.getValue();
if (value > 0) {
TimeUnit unit = this.timeout.getTimeUnit();
RemoveTask task = new RemoveTask(id);
// Make sure the expiration future map insertion happens before map removal (during task execution).
synchronized (task) {
this.expirationFutures.put(id, this.executor.schedule(task, value, unit));
}
} else if (value == 0) {
// The EJB specification allows a 0 timeout, which means the bean is immediately eligible for removal.
// However, removing it directly is faster than scheduling it for immediate removal.
remove(id);
}
}
}
}
@Override
public int getCacheSize() {
return this.entries.size();
}
@Override
public int getPassivatedCount() {
return 0;
}
@Override
public int getTotalSize() {
return this.getCacheSize();
}
class RemoveTask implements Runnable {
private final K key;
RemoveTask(K key) {
this.key = key;
}
@Override
public synchronized void run() {
if (!Thread.currentThread().isInterrupted()) {
SimpleCache.this.remove(this.key);
}
SimpleCache.this.expirationFutures.remove(this.key);
}
}
static class Entry<V> {
private final V value;
private final AtomicInteger usage = new AtomicInteger();
Entry(V value) {
this.value = value;
}
void use() {
this.usage.incrementAndGet();
}
boolean done() {
return this.usage.decrementAndGet() == 0;
}
V getValue() {
return this.value;
}
}
}