| /* |
| * 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.camel.support; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.ConcurrentMap; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.ScheduledFuture; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.locks.Lock; |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| import org.apache.camel.TimeoutMap; |
| import org.apache.camel.support.service.ServiceSupport; |
| import org.apache.camel.util.ObjectHelper; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import static java.util.Comparator.comparing; |
| import static org.apache.camel.TimeoutMap.Listener.Type.Evict; |
| import static org.apache.camel.TimeoutMap.Listener.Type.Put; |
| import static org.apache.camel.TimeoutMap.Listener.Type.Remove; |
| |
| /** |
| * Default implementation of the {@link TimeoutMap}. |
| * <p/> |
| * This implementation supports thread safe and non thread safe, in the manner you can enable locking or not. |
| * By default locking is enabled and thus we are thread safe. |
| * <p/> |
| * You must provide a {@link java.util.concurrent.ScheduledExecutorService} in the constructor which is used |
| * to schedule a background task which check for old entries to purge. This implementation will shutdown the scheduler |
| * if its being stopped. |
| * You must also invoke {@link #start()} to startup the timeout map, before its ready to be used. |
| * And you must invoke {@link #stop()} to stop the map when no longer in use. |
| */ |
| public class DefaultTimeoutMap<K, V> extends ServiceSupport implements TimeoutMap<K, V> { |
| |
| protected final Logger log = LoggerFactory.getLogger(getClass()); |
| |
| private final ConcurrentMap<K, TimeoutMapEntry<K, V>> map = new ConcurrentHashMap<>(); |
| private final ScheduledExecutorService executor; |
| private volatile ScheduledFuture<?> future; |
| private final long purgePollTime; |
| private final Lock lock; |
| |
| private final List<Listener<K, V>> listeners = new ArrayList<>(2); |
| |
| public DefaultTimeoutMap(ScheduledExecutorService executor) { |
| this(executor, 1000); |
| } |
| |
| public DefaultTimeoutMap(ScheduledExecutorService executor, long requestMapPollTimeMillis) { |
| this(executor, requestMapPollTimeMillis, true); |
| } |
| |
| public DefaultTimeoutMap(ScheduledExecutorService executor, long requestMapPollTimeMillis, boolean useLock) { |
| this(executor, requestMapPollTimeMillis, useLock ? new ReentrantLock() : NoLock.INSTANCE); |
| } |
| |
| public DefaultTimeoutMap(ScheduledExecutorService executor, long requestMapPollTimeMillis, Lock lock) { |
| ObjectHelper.notNull(executor, "ScheduledExecutorService"); |
| this.executor = executor; |
| this.purgePollTime = requestMapPollTimeMillis; |
| this.lock = lock; |
| } |
| |
| @Override |
| public V get(K key) { |
| TimeoutMapEntry<K, V> entry; |
| lock.lock(); |
| try { |
| entry = map.get(key); |
| if (entry == null) { |
| return null; |
| } |
| updateExpireTime(entry); |
| } finally { |
| lock.unlock(); |
| } |
| return entry.getValue(); |
| } |
| |
| @Override |
| public V put(K key, V value, long timeoutMillis) { |
| TimeoutMapEntry<K, V> entry = new TimeoutMapEntry<>(key, value, timeoutMillis); |
| lock.lock(); |
| try { |
| updateExpireTime(entry); |
| TimeoutMapEntry<K, V> result = map.put(key, entry); |
| return unwrap(result); |
| } finally { |
| lock.unlock(); |
| emitEvent(Put, key, value); |
| } |
| } |
| |
| @Override |
| public V putIfAbsent(K key, V value, long timeoutMillis) { |
| TimeoutMapEntry<K, V> entry = new TimeoutMapEntry<>(key, value, timeoutMillis); |
| TimeoutMapEntry<K, V> result = null; |
| lock.lock(); |
| try { |
| updateExpireTime(entry); |
| //Just make sure we don't override the old entry |
| result = map.putIfAbsent(key, entry); |
| return unwrap(result); |
| } finally { |
| lock.unlock(); |
| if (result != entry) { |
| emitEvent(Put, key, value); // conditional on map being changed |
| } |
| } |
| } |
| |
| @Override |
| public V remove(K key) { |
| V value = null; |
| lock.lock(); |
| try { |
| value = unwrap(map.remove(key)); |
| return value; |
| } finally { |
| lock.unlock(); |
| if (value != null) { |
| emitEvent(Remove, key, value); // conditional on map being changed |
| } |
| } |
| } |
| |
| @Override |
| public int size() { |
| return map.size(); |
| } |
| |
| /** |
| * The timer task which purges old requests and schedules another poll |
| */ |
| private void purgeTask() { |
| // only purge if allowed |
| if (!isRunAllowed()) { |
| log.trace("Purge task not allowed to run"); |
| return; |
| } |
| |
| log.trace("Running purge task to see if any entries have been timed out"); |
| try { |
| purge(); |
| } catch (Throwable t) { |
| // must catch and log exception otherwise the executor will now schedule next purgeTask |
| log.warn("Exception occurred during purge task. This exception will be ignored.", t); |
| } |
| } |
| |
| protected void purge() { |
| log.trace("There are {} in the timeout map", map.size()); |
| if (map.isEmpty()) { |
| return; |
| } |
| |
| long now = currentTime(); |
| |
| List<TimeoutMapEntry<K, V>> expired = new ArrayList<>(map.size()); |
| lock.lock(); |
| try { |
| // need to find the expired entries and add to the expired list |
| for (Map.Entry<K, TimeoutMapEntry<K, V>> entry : map.entrySet()) { |
| if (entry.getValue().getExpireTime() < now) { |
| if (isValidForEviction(entry.getValue())) { |
| log.debug("Evicting inactive entry ID: {}", entry.getValue()); |
| expired.add(entry.getValue()); |
| } |
| } |
| } |
| |
| // if we found any expired then we need to sort, onEviction and remove |
| if (!expired.isEmpty()) { |
| // sort according to the expired time so we got the first expired first |
| expired.sort(comparing(TimeoutMapEntry::getExpireTime)); |
| |
| // and must remove from list after we have fired the notifications |
| for (TimeoutMapEntry<K, V> entry : expired) { |
| map.remove(entry.getKey()); |
| } |
| } |
| } finally { |
| lock.unlock(); |
| for (TimeoutMapEntry<K, V> entry : expired) { |
| emitEvent(Evict, entry.getKey(), entry.getValue()); |
| } |
| } |
| } |
| |
| // Properties |
| // ------------------------------------------------------------------------- |
| |
| public long getPurgePollTime() { |
| return purgePollTime; |
| } |
| |
| public ScheduledExecutorService getExecutor() { |
| return executor; |
| } |
| |
| // Implementation methods |
| // ------------------------------------------------------------------------- |
| |
| private static <K, V> V unwrap(TimeoutMapEntry<K, V> entry) { |
| return entry == null ? null : entry.getValue(); |
| } |
| |
| @Override |
| public void addListener(Listener<K, V> listener) { |
| this.listeners.add(listener); |
| } |
| |
| private void emitEvent(Listener.Type type, K key, V value) { |
| for (Listener<K, V> listener : listeners) { |
| try { |
| listener.timeoutMapEvent(type, key, value); |
| } catch (Throwable t) { |
| // Ignore |
| } |
| } |
| } |
| |
| /** |
| * lets schedule each time to allow folks to change the time at runtime |
| */ |
| protected void schedulePoll() { |
| future = executor.scheduleWithFixedDelay(this::purgeTask, 0, purgePollTime, TimeUnit.MILLISECONDS); |
| } |
| |
| /** |
| * A hook to allow derivations to avoid evicting the current entry |
| */ |
| protected boolean isValidForEviction(TimeoutMapEntry<K, V> entry) { |
| return true; |
| } |
| |
| protected void updateExpireTime(TimeoutMapEntry<K, V> entry) { |
| long now = currentTime(); |
| entry.setExpireTime(entry.getTimeout() + now); |
| } |
| |
| protected long currentTime() { |
| return System.currentTimeMillis(); |
| } |
| |
| @Override |
| protected void doStart() throws Exception { |
| if (executor.isShutdown()) { |
| throw new IllegalStateException("The ScheduledExecutorService is shutdown"); |
| } |
| schedulePoll(); |
| } |
| |
| @Override |
| protected void doStop() throws Exception { |
| if (future != null) { |
| future.cancel(false); |
| future = null; |
| } |
| // clear map if we stop |
| map.clear(); |
| } |
| |
| } |