kafka-consumer-Consumer.adoc

Consumer Contract — Kafka Clients for Consuming Records

Consumer is the abstraction of Kafka clients that can subscribe to topics or assign partitions to consume records from.

Consumer is also a Java java.io.Closeable and so can be considered as a "a source of data that can be closed". A Consumer instance should always be closed to release system resources.

Table 1. Consumer Contract

Method	Description
assign	void assign(Collection<TopicPartition> partitions)
assignment	Set<TopicPartition> assignment()
beginningOffsets	Map<TopicPartition, Long> beginningOffsets( Collection<TopicPartition> partitions) Map<TopicPartition, Long> beginningOffsets( Collection<TopicPartition> partitions, Duration timeout)
close	void close() void close(Duration timeout) Closes the Consumer to release system resources used
commitAsync	void commitAsync() void commitAsync( Map<TopicPartition, OffsetAndMetadata> offsets, OffsetCommitCallback callback) void commitAsync( OffsetCommitCallback callback)
commitSync	void commitSync() void commitSync( Duration timeout) void commitSync( Map<TopicPartition, OffsetAndMetadata> offsets) void commitSync( Map<TopicPartition, OffsetAndMetadata> offsets, Duration timeout)
committed	OffsetAndMetadata committed( TopicPartition partition) OffsetAndMetadata committed( TopicPartition partition, Duration timeout)
endOffsets	Map<TopicPartition, Long> endOffsets( Collection<TopicPartition> partitions) Map<TopicPartition, Long> endOffsets( Collection<TopicPartition> partitions, Duration timeout)
listTopics	Map<String, List<PartitionInfo>> listTopics() Map<String, List<PartitionInfo>> listTopics( Duration timeout)
metrics	Map<MetricName, ? extends Metric> metrics()
offsetsForTimes	Map<TopicPartition, OffsetAndTimestamp> offsetsForTimes( Map<TopicPartition, Long> timestampsToSearch) Map<TopicPartition, OffsetAndTimestamp> offsetsForTimes( Map<TopicPartition, Long> timestampsToSearch, Duration timeout)
partitionsFor	List<PartitionInfo> partitionsFor( String topic) List<PartitionInfo> partitionsFor( String topic, Duration timeout)
pause	void pause(Collection<TopicPartition> partitions)
paused	Set<TopicPartition> paused()
poll	ConsumerRecords<K, V> poll(Duration timeout)
position	long position( TopicPartition partition) long position( TopicPartition partition, Duration timeout)
resume	void resume(Collection<TopicPartition> partitions)
seek	void seek(TopicPartition partition, long offset)
seekToBeginning	void seekToBeginning(Collection<TopicPartition> partitions)
seekToEnd	void seekToEnd(Collection<TopicPartition> partitions)
subscribe	void subscribe( Collection<String> topics) void subscribe( Collection<String> topics, ConsumerRebalanceListener callback) void subscribe( Pattern pattern) void subscribe( Pattern pattern, ConsumerRebalanceListener callback)
subscription	Set<String> subscription()
unsubscribe	void unsubscribe()
wakeup	void wakeup()

Table 2. Consumers

Consumer	Description
KafkaConsumer	Primary Kafka client
MockConsumer	Used for unit testing