| /** |
| * 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 kafka.consumer |
| |
| import kafka.utils.{IteratorTemplate, Logging} |
| import java.util.concurrent.{TimeUnit, BlockingQueue} |
| import kafka.serializer.Decoder |
| import java.util.concurrent.atomic.AtomicReference |
| import kafka.message.{MessageAndOffset, MessageAndMetadata} |
| |
| |
| /** |
| * An iterator that blocks until a value can be read from the supplied queue. |
| * The iterator takes a shutdownCommand object which can be added to the queue to trigger a shutdown |
| * |
| */ |
| class ConsumerIterator[T](private val channel: BlockingQueue[FetchedDataChunk], |
| consumerTimeoutMs: Int, |
| private val decoder: Decoder[T], |
| val enableShallowIterator: Boolean) |
| extends IteratorTemplate[MessageAndMetadata[T]] with Logging { |
| |
| private var current: AtomicReference[Iterator[MessageAndOffset]] = new AtomicReference(null) |
| private var currentTopicInfo:PartitionTopicInfo = null |
| private var consumedOffset: Long = -1L |
| |
| override def next(): MessageAndMetadata[T] = { |
| val item = super.next() |
| if(consumedOffset < 0) |
| throw new IllegalStateException("Offset returned by the message set is invalid %d".format(consumedOffset)) |
| currentTopicInfo.resetConsumeOffset(consumedOffset) |
| val topic = currentTopicInfo.topic |
| trace("Setting %s consumed offset to %d".format(topic, consumedOffset)) |
| ConsumerTopicStat.getConsumerTopicStat(topic).recordMessagesPerTopic(1) |
| ConsumerTopicStat.getConsumerAllTopicStat().recordMessagesPerTopic(1) |
| item |
| } |
| |
| protected def makeNext(): MessageAndMetadata[T] = { |
| var currentDataChunk: FetchedDataChunk = null |
| // if we don't have an iterator, get one |
| var localCurrent = current.get() |
| if(localCurrent == null || !localCurrent.hasNext) { |
| if (consumerTimeoutMs < 0) |
| currentDataChunk = channel.take |
| else { |
| currentDataChunk = channel.poll(consumerTimeoutMs, TimeUnit.MILLISECONDS) |
| if (currentDataChunk == null) { |
| // reset state to make the iterator re-iterable |
| resetState() |
| throw new ConsumerTimeoutException |
| } |
| } |
| if(currentDataChunk eq ZookeeperConsumerConnector.shutdownCommand) { |
| debug("Received the shutdown command") |
| channel.offer(currentDataChunk) |
| return allDone |
| } else { |
| currentTopicInfo = currentDataChunk.topicInfo |
| if (currentTopicInfo.getConsumeOffset != currentDataChunk.fetchOffset) { |
| error("consumed offset: %d doesn't match fetch offset: %d for %s;\n Consumer may lose data" |
| .format(currentTopicInfo.getConsumeOffset, currentDataChunk.fetchOffset, currentTopicInfo)) |
| currentTopicInfo.resetConsumeOffset(currentDataChunk.fetchOffset) |
| } |
| localCurrent = if (enableShallowIterator) currentDataChunk.messages.shallowIterator |
| else currentDataChunk.messages.iterator |
| current.set(localCurrent) |
| } |
| } |
| val item = localCurrent.next() |
| consumedOffset = item.offset |
| |
| new MessageAndMetadata(decoder.toEvent(item.message), currentTopicInfo.topic) |
| } |
| |
| def clearCurrentChunk() { |
| try { |
| info("Clearing the current data chunk for this consumer iterator") |
| current.set(null) |
| } |
| } |
| } |
| |
| class ConsumerTimeoutException() extends RuntimeException() |
| |