/**
* 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 com.leansoft.luxun.consumer;
import java.util.Iterator;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.leansoft.luxun.common.annotations.NotThreadSafe;
import com.leansoft.luxun.common.exception.ConsumerTimeoutException;
import com.leansoft.luxun.message.Message;
import com.leansoft.luxun.mx.ConsumerTopicStat;
import com.leansoft.luxun.serializer.Decoder;
import com.leansoft.luxun.utils.IteratorTemplate;
/**
*
* @author bulldog
*
*/
@NotThreadSafe
public class ConsumerIterator<T> extends IteratorTemplate<T> {
private final Logger logger = LoggerFactory.getLogger(ConsumerIterator.class);
final String topic;
final BlockingQueue<FetchedDataChunk> queue;
final int consumerTimeoutMs;
final Decoder<T> decoder;
private AtomicReference<Iterator<Message>> current = new AtomicReference<Iterator<Message>>(null);
public ConsumerIterator(String topic, BlockingQueue<FetchedDataChunk> queue, int consumerTimeoutMs,
Decoder<T> decoder) {
super();
this.topic = topic;
this.queue = queue;
this.consumerTimeoutMs = consumerTimeoutMs;
this.decoder = decoder;
}
@Override
public T next() {
T decodedMessage = super.next();
ConsumerTopicStat.getConsumerTopicStat(topic).recordMessagesPerTopic(1);
return decodedMessage;
}
@Override
protected T makeNext() {
try {
return makeNext0();
} catch (InterruptedException e) {
throw new RuntimeException(e.getMessage(), e);
}
}
protected T makeNext0() throws InterruptedException {
FetchedDataChunk currentDataChunk = null;
Iterator<Message> localCurrent = current.get();
if (localCurrent == null || !localCurrent.hasNext()) {
if (consumerTimeoutMs < 0) {
currentDataChunk = queue.take();
} else {
currentDataChunk = queue.poll(consumerTimeoutMs, TimeUnit.MILLISECONDS);
if (currentDataChunk == null) {
resetState();
throw new ConsumerTimeoutException("consumer timeout in " + consumerTimeoutMs + " ms");
}
}
if (currentDataChunk == StreamFactory.SHUTDOWN_COMMAND) {
logger.warn("Now closing the message stream");
queue.offer(currentDataChunk); // maybe there are other consuming threads waiting on the same queue
return allDone();
} else {
// consume an message
localCurrent = currentDataChunk.messageList.iterator();
current.set(localCurrent);
}
}
Message message = localCurrent.next();
return decoder.toEvent(message);
}
}