qpid/java/broker/src/main/java/org/apache/qpid/server/handler/TxRollbackHandler.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,
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package org.apache.qpid.server.handler;

import org.apache.qpid.AMQException;
import org.apache.qpid.framing.AMQMethodBody;
import org.apache.qpid.framing.MethodRegistry;
import org.apache.qpid.framing.TxRollbackBody;
import org.apache.qpid.server.AMQChannel;
import org.apache.qpid.server.protocol.AMQProtocolSession;
import org.apache.qpid.server.state.AMQStateManager;
import org.apache.qpid.server.state.StateAwareMethodListener;

public class TxRollbackHandler implements StateAwareMethodListener<TxRollbackBody>
{
    private static TxRollbackHandler _instance = new TxRollbackHandler();

    public static TxRollbackHandler getInstance()
    {
        return _instance;
    }

    private TxRollbackHandler()
    {
    }

    public void methodReceived(AMQStateManager stateManager, TxRollbackBody body, final int channelId) throws AMQException
    {
        final AMQProtocolSession session = stateManager.getProtocolSession();

        try
        {
            AMQChannel channel = session.getChannel(channelId);

            if (channel == null)
            {
                throw body.getChannelNotFoundException(channelId);
            }



            final MethodRegistry methodRegistry = session.getMethodRegistry();
            final AMQMethodBody responseBody = methodRegistry.createTxRollbackOkBody();

            Runnable task = new Runnable()
            {

                public void run()
                {
                    session.writeFrame(responseBody.generateFrame(channelId));
                }
            };

            channel.rollback(task);

            //Now resend all the unacknowledged messages back to the original subscribers.
            //(Must be done after the TxnRollback-ok response).
            // Why, are we not allowed to send messages back to client before the ok method?
            channel.resend(false);

        }
        catch (AMQException e)
        {
            throw body.getChannelException(e.getErrorCode(), "Failed to rollback: " + e.getMessage());
        }
    }
}