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/*
*
* Copyright (c) 2006 The Apache Software Foundation
*
* Licensed 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.ack;
import org.apache.qpid.AMQException;
import org.apache.qpid.server.txn.TxnOp;
import java.util.LinkedList;
import java.util.List;
/**
* A TxnOp implementation for handling accumulated acks
*/
public class TxAck implements TxnOp
{
private final UnacknowledgedMessageMap _map;
private final List <UnacknowledgedMessage> _unacked = new LinkedList<UnacknowledgedMessage>();
private final List<Long> _individual = new LinkedList<Long>();
private long _deliveryTag;
private boolean _multiple;
public TxAck(UnacknowledgedMessageMap map)
{
_map = map;
}
public void update(long deliveryTag, boolean multiple)
{
if (!multiple)
{
//have acked a single message that is not part of
//the previously acked region so record
//individually
_individual.add(deliveryTag);//_multiple && !multiple
}
else if (deliveryTag > _deliveryTag)
{
//have simply moved the last acked message on a
//bit
_deliveryTag = deliveryTag;
_multiple = true;
}
}
public void consolidate()
{
//lookup all the unacked messages that have been acked in this transaction
if (_multiple)
{
//get all the unacked messages for the accumulated
//multiple acks
_map.collect(_deliveryTag, true, _unacked);
}
//get any unacked messages for individual acks outside the
//range covered by multiple acks
for (long tag : _individual)
{
if(_deliveryTag < tag)
{
_map.collect(tag, false, _unacked);
}
}
}
public boolean checkPersistent() throws AMQException
{
//if any of the messages in unacked are persistent the txn
//buffer must be marked as persistent:
for (UnacknowledgedMessage msg : _unacked)
{
if (msg.message.isPersistent())
{
return true;
}
}
return false;
}
public void prepare() throws AMQException
{
//make persistent changes, i.e. dequeue and decrementReference
for (UnacknowledgedMessage msg : _unacked)
{
msg.discard();
}
}
public void undoPrepare()
{
//decrementReference is annoyingly untransactional (due to
//in memory counter) so if we failed in prepare for full
//txn, this op will have to compensate by fixing the count
//in memory (persistent changes will be rolled back by store)
for (UnacknowledgedMessage msg : _unacked)
{
msg.message.incrementReference();
}
}
public void commit()
{
//remove the unacked messages from the channels map
_map.remove(_unacked);
}
public void rollback()
{
}
}
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