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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.ack;
import java.util.List;
import java.util.Map;
import java.util.HashMap;
import java.util.ArrayList;
import org.apache.qpid.AMQException;
import org.apache.qpid.server.store.StoreContext;
import org.apache.qpid.server.txn.TxnOp;
import org.apache.qpid.server.queue.QueueEntry;
/**
* A TxnOp implementation for handling accumulated acks
*/
public class TxAck implements TxnOp
{
private final UnacknowledgedMessageMap _map;
private final Map<Long, QueueEntry> _unacked = new HashMap<Long,QueueEntry>();
private List<Long> _individual;
private long _deliveryTag;
private boolean _multiple;
public TxAck(UnacknowledgedMessageMap map)
{
_map = map;
}
public void update(long deliveryTag, boolean multiple)
{
_unacked.clear();
if (!multiple)
{
if(_individual == null)
{
_individual = new ArrayList<Long>();
}
//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()
{
if(_unacked.isEmpty())
{
//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);
}
if(_individual != null)
{
//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
{
consolidate();
//if any of the messages in unacked are persistent the txn
//buffer must be marked as persistent:
for (QueueEntry msg : _unacked.values())
{
if (msg.isPersistent())
{
return true;
}
}
return false;
}
public void prepare(StoreContext storeContext) throws AMQException
{
//make persistent changes, i.e. dequeue and decrementReference
for (QueueEntry msg : _unacked.values())
{
//Message has been ack so dequeueAndDelete it.
// If the message is persistent and this is the last QueueEntry that uses it then the data will be removed
// from the transaciton log
msg.dequeueAndDelete(storeContext);
}
}
public void undoPrepare()
{
//As this is transaction the above dequeueAndDelete will only request the message be dequeue from the
// transactionLog. Only when the transaction succesfully completes will it perform any
// update of the internal transactionLog reference counting and any resulting message data deletion.
// The success or failure of the data deletion is not important to this transaction only that the ack has been
// successfully recorded.
}
public void commit(StoreContext storeContext)
{
//remove the unacked messages from the channels map
_map.remove(_unacked);
}
public void rollback(StoreContext storeContext)
{
}
}
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