/*
*
* 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.util.Enumeration;
import java.util.Iterator;
import java.util.LinkedList;
import org.apache.qpid.api.Message;
import org.apache.qpid.management.Messages;
import org.apache.qpid.management.Protocol;
import org.apache.qpid.nclient.util.ByteBufferMessage;
import org.apache.qpid.transport.codec.BBDecoder;
import org.apache.qpid.transport.util.Logger;
/**
* The message tokenizer class allows a multi message listener to break a
* message into tokens where each token is itself a valid AMQP message.
*
* @author Andrea Gazzarini
* @see QPID-1368
*/
class MessageTokenizer implements Enumeration<Message>
{
private final static Logger LOGGER = Logger.get(MessageTokenizer.class);
static byte [] MAGIC_NUMBER_BYTES;
private LinkedList<Message> _messages = new LinkedList<Message>();
private Iterator<Message> _iterator;
static
{
try
{
MAGIC_NUMBER_BYTES = Protocol.MAGIC_NUMBER.getBytes("UTF-8");
} catch(Exception exception)
{
throw new ExceptionInInitializerError(exception);
}
}
/**
* Builds a new Message tokenizer with the given message.
* Note that if the given message is not a "compound" message this tokenizer will producer only one token;
* That is, the token is a message equals to the given message.
*
* @param compoundMessage the compound message
* @throws IOException when it's not possible to read the given message content.
*/
MessageTokenizer(Message compoundMessage) throws IOException
{
build(compoundMessage);
}
public boolean hasMoreElements()
{
return _iterator.hasNext();
}
public Message nextElement()
{
return _iterator.next();
}
/**
* Retruns the number of the tokens produced by this tokenizer.
*
* @return the number of the tokens produced by this tokenizer.
*/
public int countTokens()
{
return _messages.size();
}
// Internal methods used for splitting the multi message byte array.
int indexOf(byte[] source, int startIndex)
{
int currentSourceIndex;
int currentExampleIndex;
if (startIndex + 3 > source.length)
return -1;
for (currentSourceIndex = startIndex; currentSourceIndex <= source.length - 3; currentSourceIndex++)
{
for (currentExampleIndex = 0; currentExampleIndex < 3; currentExampleIndex++)
{
if (source[currentSourceIndex + currentExampleIndex] != MAGIC_NUMBER_BYTES[currentExampleIndex])
break;
}
if (currentExampleIndex == 3)
return currentSourceIndex;
}
return -1;
}
// Internal method used for building the tokens.
private void build(Message compoundMessage) throws IOException
{
int startIndex = 0;
int indexOfMagicNumber = 0;
BBDecoder decoder = new BBDecoder();
decoder.init(compoundMessage.readData());
byte [] source = decoder.readReaminingBytes();
int howManyTokens = 1;
while ((indexOfMagicNumber = indexOf(source, startIndex+1)) != -1)
{
addMessageToken(source, startIndex, (indexOfMagicNumber-startIndex));
startIndex = indexOfMagicNumber;
howManyTokens++;
}
addMessageToken(source, startIndex, (source.length-startIndex));
_iterator = _messages.iterator();
LOGGER.debug(Messages.QMAN_200031_COMPOUND_MESSAGE_CONTAINS,howManyTokens);
};
// Builds & adds a new "message" token
private void addMessageToken(byte [] source,int startIndex,int length) throws IOException
{
byte [] messageData = new byte[length];
System.arraycopy(source, startIndex, messageData, 0, messageData.length);
Message message = new ByteBufferMessage();
message.appendData(messageData);
_messages.add(message);
}
}