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/*
*
* 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.subscription;
import org.apache.qpid.server.message.AMQMessageHeader;
import org.apache.qpid.server.message.ServerMessage;
import org.apache.qpid.server.queue.AMQQueue;
import org.apache.qpid.server.queue.QueueEntryVisitor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.qpid.server.queue.QueueEntry;
import java.util.Iterator;
import java.util.concurrent.ConcurrentHashMap;
public class AssignedSubscriptionMessageGroupManager implements MessageGroupManager
{
private static final Logger _logger = LoggerFactory.getLogger(AssignedSubscriptionMessageGroupManager.class);
private final String _groupId;
private String _defaultGroup;
private final ConcurrentHashMap<Integer, Subscription> _groupMap = new ConcurrentHashMap<Integer, Subscription>();
private final int _groupMask;
public AssignedSubscriptionMessageGroupManager(final String groupId, String defaultGroup, final int maxGroups)
{
_groupId = groupId;
_defaultGroup = defaultGroup;
_groupMask = pow2(maxGroups)-1;
}
private static int pow2(final int i)
{
int val = 1;
while(val < i)
{
val<<=1;
}
return val;
}
private Object getKey(QueueEntry entry)
{
ServerMessage<?> message = entry.getMessage();
AMQMessageHeader messageHeader = message == null ? null : message.getMessageHeader();
Object groupVal = messageHeader == null ? _defaultGroup : messageHeader.getHeader(_groupId);
if(groupVal == null)
{
groupVal = _defaultGroup;
}
return groupVal;
}
public Subscription getAssignedSubscription(final QueueEntry entry)
{
Object groupVal = getKey(entry);
return groupVal == null ? null : _groupMap.get(groupVal.hashCode() & _groupMask);
}
public boolean acceptMessage(Subscription sub, QueueEntry entry)
{
if(assignMessage(sub, entry))
{
return entry.acquire(sub);
}
else
{
return false;
}
}
private boolean assignMessage(Subscription sub, QueueEntry entry)
{
Object groupVal = getKey(entry);
if(groupVal == null)
{
return true;
}
else
{
Integer group = groupVal.hashCode() & _groupMask;
Subscription assignedSub = _groupMap.get(group);
if(assignedSub == sub)
{
return true;
}
else
{
if(assignedSub == null)
{
if(_logger.isDebugEnabled())
{
_logger.debug("Assigning group " + groupVal + " to sub " + sub);
}
assignedSub = _groupMap.putIfAbsent(group, sub);
return assignedSub == null || assignedSub == sub;
}
else
{
return false;
}
}
}
}
public QueueEntry findEarliestAssignedAvailableEntry(Subscription sub, AMQQueue queue)
{
EntryFinder visitor = new EntryFinder(sub);
queue.visit(visitor);
return visitor.getEntry();
}
private class EntryFinder implements QueueEntryVisitor
{
private QueueEntry _entry;
private Subscription _sub;
public EntryFinder(final Subscription sub)
{
_sub = sub;
}
public boolean visit(final QueueEntry entry)
{
if(!entry.isAvailable())
{
return false;
}
Object groupId = getKey(entry);
if(groupId == null)
{
//message is not part of a group, anyone who wants it can consume it
_entry = entry;
return true;
}
Integer group = groupId.hashCode() & _groupMask;
Subscription assignedSub = _groupMap.get(group);
if(assignedSub == _sub || assignedSub == null)
{
//group is either not assigned or is assigned to this subscription
_entry = entry;
return true;
}
else
{
//group is already assigned to another subscription
return false;
}
}
public QueueEntry getEntry()
{
return _entry;
}
}
public void clearAssignments(Subscription sub)
{
Iterator<Subscription> subIter = _groupMap.values().iterator();
while(subIter.hasNext())
{
if(subIter.next() == sub)
{
subIter.remove();
}
}
}
}
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