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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.management.domain.services;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.qpid.api.Message;
import org.apache.qpid.management.Messages;
import org.apache.qpid.management.Protocol;
import org.apache.qpid.management.domain.handler.base.IMessageHandler;
import org.apache.qpid.management.domain.model.DomainModel;
import org.apache.qpid.nclient.util.MessageListener;
import org.apache.qpid.transport.codec.BBDecoder;
import org.apache.qpid.transport.util.Logger;
/**
* Message listener used for processing incoming messages.
* So it is installed as a consumer on a specific channel and when a new message arrives:
*
* 1) Performs a sanity check on the message (magic number, sequence number)
* 2) Extracts the opcode and looks for one message handler associated with that opcode.
* 3) If a message handler is found the delegates the message processing; otherwise a log message is written to indicate
* that the message will be skipped.
*
* @author Andrea Gazzarini
*/
class BrokerMessageListener implements MessageListener
{
private final static Logger LOGGER = Logger.get(BrokerMessageListener.class);
private static class Log
{
// Debugs the content of the incoming message.
static void debugIncomingMessage(ByteBuffer message)
{
if (LOGGER.isDebugEnabled())
{
LOGGER.debug(Messages.QMAN_200001_INCOMING_MESSAGE_HAS_BEEN_RECEIVED, Arrays.toString(message.array()));
}
}
// Debugs all the configured handlers.
static void debugConfiguredHandlers (Map<Character, IMessageHandler> _handlers)
{
if (LOGGER.isDebugEnabled())
{
for (Entry<Character, IMessageHandler> entry : _handlers.entrySet())
{
LOGGER.debug(Messages.QMAN_200002_OPCODE_HANDLER_ASSOCIATION,entry.getKey(),entry.getValue());
}
}
}
}
Map<Character, IMessageHandler> _handlers = new HashMap<Character, IMessageHandler>();
private DomainModel _domainModel;
/**
* Builds a new message listener with the given broker domain model.
*
* @param model the managed broker domain model.
*/
BrokerMessageListener(DomainModel model)
{
this._domainModel = model;
}
/**
* When a new message arrives this method is called.
* 1) Performs a sanity check on the message (magic number, sequence number)
* 2) Extracts the opcode and looks for one message handler associated with that opcode.
* 3) If a message handler is found the delegates the message processing; otherwise a log message is written to indicate
* that the message will be skipped.
*
* @param message the incoming message.
*/
public void onMessage (Message compoundMessage)
{
try
{
MessageTokenizer tokenizer = new MessageTokenizer(compoundMessage);
while (tokenizer.hasMoreElements())
{
dispatch(tokenizer.nextElement());
}
} catch(IOException exception)
{
LOGGER.error(exception,Messages.QMAN_100002_MESSAGE_READ_FAILURE);
} catch(Exception exception)
{
LOGGER.error(exception,Messages.QMAN_100003_MESSAGE_PROCESS_FAILURE);
}
}
/**
* Configures a new handler with this listener.
* After that, each time a message arrives with the specified opcode, this handler will be responsible for
* processing.
* Note that calling this method will switch this listener to a WORKING state.
*
* @param opcode the operation code.
* @param handler the message handler.
*/
void setHandlers(Map<Character, IMessageHandler> handlers)
{
for (Entry<Character, IMessageHandler> entry : handlers.entrySet())
{
char opcode = entry.getKey();
IMessageHandler handler = entry.getValue();
try
{
handler.setDomainModel(_domainModel);
_handlers.put(opcode, handler);
} catch (Exception exception) {
LOGGER.error(exception,
Messages.QMAN_100004_HANDLER_INITIALIZATION_FAILURE,
opcode);
}
}
}
/**
* Dispatches the given message to the appropriate handler.
*
* @param message
* the incoming message.
* @throws IOException
* when the message content cannot be read.
*/
private void dispatch(Message message) throws IOException
{
ByteBuffer buffer = message.readData();
String magicNumber = new String(new byte[] {buffer.get(),buffer.get(),buffer.get()});
if (!Protocol.MAGIC_NUMBER.equals(magicNumber))
{
LOGGER.error(Messages.QMAN_100001_BAD_MAGIC_NUMBER_FAILURE,magicNumber);
return;
}
char opcode = (char)buffer.get();
IMessageHandler handler = _handlers.get(opcode);
if (handler != null)
{
BBDecoder decoder = new BBDecoder();
decoder.init(buffer);
LOGGER.debug(Messages.QMAN_200003_MESSAGE_FORWARDING,opcode,handler);
handler.process(decoder,decoder.readSequenceNo());
} else
{
LOGGER.warn(Messages.QMAN_300001_MESSAGE_DISCARDED,opcode);
Log.debugConfiguredHandlers(_handlers);
}
}
}
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