RC9/qpid/java/broker/src/main/java/org/apache/qpid/server/queue/AMQPriorityQueue.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.
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*/
package org.apache.qpid.server.queue;

import org.apache.qpid.framing.AMQShortString;
import org.apache.qpid.server.virtualhost.VirtualHost;
import org.apache.qpid.server.subscription.SubscriptionList;
import org.apache.qpid.server.subscription.Subscription;
import org.apache.qpid.AMQException;

public class AMQPriorityQueue extends SimpleAMQQueue
{
    protected AMQPriorityQueue(final AMQShortString name,
                               final boolean durable,
                               final AMQShortString owner,
                               final boolean autoDelete,
                               final VirtualHost virtualHost,
                               int priorities)
            throws AMQException
    {
        super(name, durable, owner, autoDelete, virtualHost, new PriorityQueueList.Factory(priorities));
    }

    public int getPriorities()
    {
        return ((PriorityQueueList) _entries).getPriorities();
    }

    @Override
    protected void checkSubscriptionsNotAheadOfDelivery(final QueueEntry entry)
    {
        // check that all subscriptions are not in advance of the entry
        SubscriptionList.SubscriptionNodeIterator subIter = _subscriptionList.iterator();
        while(subIter.advance() && !entry.isAcquired())
        {
            final Subscription subscription = subIter.getNode().getSubscription();
            QueueEntry subnode = subscription.getLastSeenEntry();
            while(subnode != null && entry.compareTo(subnode) < 0 && !entry.isAcquired())
            {
                if(subscription.setLastSeenEntry(subnode,entry))
                {
                    break;
                }
                else
                {
                    subnode = subscription.getLastSeenEntry();
                }
            }

        }
    }

}