/* | |
* | |
* 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); | |
} | |
} |