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Diffstat (limited to 'java/broker/src/main/java/org/apache/qpid/server/queue/ConcurrentSelectorDeliveryManager.java')
| -rw-r--r-- | java/broker/src/main/java/org/apache/qpid/server/queue/ConcurrentSelectorDeliveryManager.java | 352 |
1 files changed, 352 insertions, 0 deletions
diff --git a/java/broker/src/main/java/org/apache/qpid/server/queue/ConcurrentSelectorDeliveryManager.java b/java/broker/src/main/java/org/apache/qpid/server/queue/ConcurrentSelectorDeliveryManager.java new file mode 100644 index 0000000000..d8bb6e1948 --- /dev/null +++ b/java/broker/src/main/java/org/apache/qpid/server/queue/ConcurrentSelectorDeliveryManager.java @@ -0,0 +1,352 @@ +/* + * + * 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.qpid.server.queue; + +import org.apache.log4j.Logger; +import org.apache.qpid.AMQException; +import org.apache.qpid.util.ConcurrentLinkedQueueAtomicSize; +import org.apache.qpid.configuration.Configured; +import org.apache.qpid.framing.ContentBody; +import org.apache.qpid.server.configuration.Configurator; + +import java.util.ArrayList; +import java.util.Iterator; +import java.util.List; +import java.util.Queue; +import java.util.concurrent.Executor; +import java.util.concurrent.locks.ReentrantLock; +import java.util.concurrent.atomic.AtomicBoolean; + + +/** + * Manages delivery of messages on behalf of a queue + */ +public class ConcurrentSelectorDeliveryManager implements DeliveryManager +{ + private static final Logger _log = Logger.getLogger(ConcurrentSelectorDeliveryManager.class); + + @Configured(path = "advanced.compressBufferOnQueue", + defaultValue = "false") + public boolean compressBufferOnQueue; + /** + * Holds any queued messages + */ + private final Queue<AMQMessage> _messages = new ConcurrentLinkedQueueAtomicSize<AMQMessage>(); + //private int _messageCount; + /** + * Ensures that only one asynchronous task is running for this manager at + * any time. + */ + private final AtomicBoolean _processing = new AtomicBoolean(); + /** + * The subscriptions on the queue to whom messages are delivered + */ + private final SubscriptionManager _subscriptions; + + /** + * A reference to the queue we are delivering messages for. We need this to be able + * to pass the code that handles acknowledgements a handle on the queue. + */ + private final AMQQueue _queue; + + + /** + * Lock used to ensure that an channel that becomes unsuspended during the start of the queueing process is forced + * to wait till the first message is added to the queue. This will ensure that the _queue has messages to be delivered + * via the async thread. + * <p/> + * Lock is used to control access to hasQueuedMessages() and over the addition of messages to the queue. + */ + private ReentrantLock _lock = new ReentrantLock(); + + + ConcurrentSelectorDeliveryManager(SubscriptionManager subscriptions, AMQQueue queue) + { + + //Set values from configuration + Configurator.configure(this); + + if (compressBufferOnQueue) + { + _log.warn("Compressing Buffers on queue."); + } + + _subscriptions = subscriptions; + _queue = queue; + } + + + private boolean addMessageToQueue(AMQMessage msg) + { + // Shrink the ContentBodies to their actual size to save memory. + if (compressBufferOnQueue) + { + Iterator it = msg.getContentBodies().iterator(); + while (it.hasNext()) + { + ContentBody cb = (ContentBody) it.next(); + cb.reduceBufferToFit(); + } + } + + _messages.offer(msg); + + return true; + } + + + public boolean hasQueuedMessages() + { + _lock.lock(); + try + { + return !_messages.isEmpty(); + } + finally + { + _lock.unlock(); + } + } + + public int getQueueMessageCount() + { + return getMessageCount(); + } + + /** + * This is an EXPENSIVE opperation to perform with a ConcurrentLinkedQueue as it must run the queue to determine size. + * The ConcurrentLinkedQueueAtomicSize uses an AtomicInteger to record the number of elements on the queue. + * + * @return int the number of messages in the delivery queue. + */ + private int getMessageCount() + { + return _messages.size(); + } + + + public synchronized List<AMQMessage> getMessages() + { + return new ArrayList<AMQMessage>(_messages); + } + + public synchronized void removeAMessageFromTop() throws AMQException + { + AMQMessage msg = poll(); + if (msg != null) + { + msg.dequeue(_queue); + } + } + + public synchronized void clearAllMessages() throws AMQException + { + AMQMessage msg = poll(); + while (msg != null) + { + msg.dequeue(_queue); + msg = poll(); + } + } + + + private AMQMessage getNextMessage(Queue<AMQMessage> messages) + { + AMQMessage message = messages.peek(); + + while (message != null && message.taken()) + { + //remove the already taken message + messages.poll(); + // try the next message + message = messages.peek(); + } + return message; + } + + public void sendNextMessage(Subscription sub, Queue<AMQMessage> messageQueue, AMQQueue queue) + { + AMQMessage message = null; + try + { + message = getNextMessage(messageQueue); + + // message will be null if we have no messages in the messageQueue. + if (message == null) + { + return; + } + _log.info("Async Delivery Message:" + message + " to :" + sub); + + sub.send(message, queue); + message.setDeliveredToConsumer(); + + //remove sent message from our queue. + messageQueue.poll(); + } + catch (FailedDequeueException e) + { + message.release(); + _log.error("Unable to deliver message as dequeue failed: " + e, e); + } + } + + /** + * Only one thread should ever execute this method concurrently, but + * it can do so while other threads invoke deliver(). + */ + private void processQueue() + { + // Continue to process delivery while we haveSubscribers and messages + boolean hasSubscribers = _subscriptions.hasActiveSubscribers(); + + while (hasSubscribers && hasQueuedMessages()) + { + for (Subscription sub : _subscriptions.getSubscriptions()) + { + if (!sub.isSuspended()) + { + if (sub.hasFilters()) + { + sendNextMessage(sub, sub.getPreDeliveryQueue(), _queue); + } + else + { + sendNextMessage(sub, _messages, _queue); + } + + hasSubscribers = true; + } + else + { + hasSubscribers = false; + } + } + } + } + + private AMQMessage poll() + { + return _messages.poll(); + } + + public void deliver(String name, AMQMessage msg) throws FailedDequeueException + { + _log.info("deliver :" + msg); + + //Check if we have someone to deliver the message to. + _lock.lock(); + try + { + Subscription s = _subscriptions.nextSubscriber(msg); + + if (s == null) //no-one can take the message right now. + { + _log.info("Testing Message(" + msg + ") for Queued Delivery"); + if (!msg.isImmediate()) + { + addMessageToQueue(msg); + + //release lock now message is on queue. + _lock.unlock(); + + //Pre Deliver to all subscriptions + _log.info("We have " + _subscriptions.getSubscriptions().size() + " subscribers to give the message to."); + for (Subscription sub : _subscriptions.getSubscriptions()) + { + + // stop if the message gets delivered whilst PreDelivering if we have a shared queue. + if (_queue.isShared() && msg.getDeliveredToConsumer()) + { + _log.info("Stopping PreDelivery as message(" + msg + ") is already delivered."); + continue; + } + + // Only give the message to those that want them. + if (sub.hasFilters() && sub.hasInterest(msg)) + { + sub.enqueueForPreDelivery(msg); + } + } + } + } + else + { + //release lock now + _lock.unlock(); + + _log.info("Delivering Message:" + msg + " to(" + System.identityHashCode(s) + ") :" + s); + //Deliver the message + s.send(msg, _queue); + msg.setDeliveredToConsumer(); + } + } + finally + { + //ensure lock is released + if (_lock.isLocked()) + { + _lock.unlock(); + } + } + } + + Runner asyncDelivery = new Runner(); + + private class Runner implements Runnable + { + public void run() + { + boolean running = true; + while (running) + { + processQueue(); + + //Check that messages have not been added since we did our last peek(); + // Synchronize with the thread that adds to the queue. + // If the queue is still empty then we can exit + + if (!(hasQueuedMessages() && _subscriptions.hasActiveSubscribers())) + { + running = false; + _processing.set(false); + } + } + } + } + + public void processAsync(Executor executor) + { + _log.debug("Processing Async. Queued:" + hasQueuedMessages() + "(" + getQueueMessageCount() + ")" + + " Active:" + _subscriptions.hasActiveSubscribers() + + " Processing:" + _processing.get()); + + if (hasQueuedMessages() && _subscriptions.hasActiveSubscribers()) + { + //are we already running? if so, don't re-run + if (_processing.compareAndSet(false, true)) + { + executor.execute(asyncDelivery); + } + } + } + +} |