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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.txn;
import org.apache.qpid.AMQException;
import org.apache.qpid.server.ack.TxAck;
import org.apache.qpid.server.ack.UnacknowledgedMessageMap;
import org.apache.qpid.server.queue.AMQMessage;
import org.apache.qpid.server.queue.AMQQueue;
import org.apache.qpid.server.RequiredDeliveryException;
import org.apache.qpid.server.store.MessageStore;
import java.util.List;
/**
* A transactional context that only supports local transactions.
*/
public class LocalTransactionalContext implements TransactionalContext
{
private final TxnBuffer _txnBuffer;
/**
* We keep hold of the ack operation so that we can consolidate acks, i.e. multiple acks within a txn are
* consolidated into a single operation
*/
private TxAck _ackOp;
private List<RequiredDeliveryException> _returnMessages;
private final MessageStore _messageStore;
private boolean _inTran = false;
public LocalTransactionalContext(MessageStore messageStore,
TxnBuffer txnBuffer, List<RequiredDeliveryException> returnMessages)
{
_messageStore = messageStore;
_txnBuffer = txnBuffer;
_returnMessages = returnMessages;
_txnBuffer.enlist(new StoreMessageOperation(messageStore));
}
public void rollback() throws AMQException
{
_txnBuffer.rollback();
}
public void deliver(AMQMessage message, AMQQueue queue) throws AMQException
{
// don't create a transaction unless needed
if (message.isPersistent())
{
_txnBuffer.containsPersistentChanges();
}
// A publication will result in the enlisting of several
// TxnOps. The first is an op that will store the message.
// Following that (and ordering is important), an op will
// be added for every queue onto which the message is
// enqueued. Finally a cleanup op will be added to decrement
// the reference associated with the routing.
_txnBuffer.enlist(new DeliverMessageOperation(message, queue));
_txnBuffer.enlist(new CleanupMessageOperation(message, _returnMessages));
}
private void checkAck(long deliveryTag, UnacknowledgedMessageMap unacknowledgedMessageMap) throws AMQException
{
if (!unacknowledgedMessageMap.contains(deliveryTag))
{
throw new AMQException("Ack with delivery tag " + deliveryTag + " not known for channel");
}
}
public void acknowledgeMessage(long deliveryTag, long lastDeliveryTag, boolean multiple,
UnacknowledgedMessageMap unacknowledgedMessageMap) throws AMQException
{
//check that the tag exists to give early failure
if (!multiple || deliveryTag > 0)
{
checkAck(deliveryTag, unacknowledgedMessageMap);
}
//we use a single txn op for all acks and update this op
//as new acks come in. If this is the first ack in the txn
//we will need to create and enlist the op.
if (_ackOp == null)
{
_ackOp = new TxAck(unacknowledgedMessageMap);
_txnBuffer.enlist(_ackOp);
}
// update the op to include this ack request
if (multiple && deliveryTag == 0)
{
// if have signalled to ack all, that refers only
// to all at this time
_ackOp.update(lastDeliveryTag, multiple);
}
else
{
_ackOp.update(deliveryTag, multiple);
}
}
public void messageFullyReceived(boolean persistent) throws AMQException
{
// Not required in this transactional context
}
public void beginTranIfNecessary() throws AMQException
{
if (!_inTran)
{
_messageStore.beginTran();
_inTran = true;
}
}
public void commit() throws AMQException
{
if (_ackOp != null)
{
_ackOp.consolidate();
if (_ackOp.checkPersistent())
{
_txnBuffer.containsPersistentChanges();
}
//already enlisted, after commit will reset regardless of outcome
_ackOp = null;
}
_txnBuffer.commit();
//TODO: may need to return 'immediate' messages at this point
}
}
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