broker-core/src/main/java/org/apache/qpid/server/queue/OutOfOrderQueue.java

/*
 *
 * 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 java.util.Iterator;
import java.util.Map;

import org.apache.qpid.server.virtualhost.QueueManagingVirtualHost;

public abstract class OutOfOrderQueue<X extends OutOfOrderQueue<X>> extends AbstractQueue<X>
{

    OutOfOrderQueue(Map<String, Object> attributes, QueueManagingVirtualHost<?> virtualHost)
    {
        super(attributes, virtualHost);
    }

    @Override
    protected void checkConsumersNotAheadOfDelivery(final QueueEntry entry)
    {
        // check that all consumers are not in advance of the entry
        Iterator<QueueConsumer<?,?>> consumerIterator = getQueueConsumerManager().getAllIterator();

        while (consumerIterator.hasNext() && !entry.isAcquired())
        {
            QueueConsumer<?,?> consumer = consumerIterator.next();

            if(!consumer.isClosed())
            {
                QueueContext context = consumer.getQueueContext();
                if(context != null)
                {
                    QueueEntry released = context.getReleasedEntry();
                    while(!entry.isAcquired() && (released == null || released.compareTo(entry) > 0))
                    {
                        if(QueueContext._releasedUpdater.compareAndSet(context,released,entry))
                        {
                            break;
                        }
                        else
                        {
                            released = context.getReleasedEntry();
                        }
                    }
                }
            }
        }
    }

}