io.smallrye.reactive.messaging.kafka

Interface KafkaConsumer<K,V>

Type Parameters:

K - the type of key

V - the type of value

All Known Implementing Classes:

ReactiveKafkaConsumer

public interface KafkaConsumer<K,V>

Kafka Consumer API.

Unlike Consumer, this API is asynchronous and make sure that the actions are executed on the Kafka polling thread.

Method Summary

Modifier and Type	Method and Description
io.smallrye.mutiny.Uni<Void>	commit(Map<org.apache.kafka.common.TopicPartition,org.apache.kafka.clients.consumer.OffsetAndMetadata> map) Commits the offsets
io.smallrye.mutiny.Uni<Map<org.apache.kafka.common.TopicPartition,org.apache.kafka.clients.consumer.OffsetAndMetadata>>	committed(org.apache.kafka.common.TopicPartition... tps) Retrieved the last committed offset for each topic/partition
io.smallrye.mutiny.Uni<Set<org.apache.kafka.common.TopicPartition>>	getAssignments() Retrieves the current assignments of the consumer.
io.smallrye.mutiny.Uni<Map<org.apache.kafka.common.TopicPartition,Long>>	getPositions() Retrieves the next positions for each assigned topic/partitions
io.smallrye.mutiny.Uni<Set<org.apache.kafka.common.TopicPartition>>	pause() Pauses the consumption of records.
io.smallrye.mutiny.Uni<Set<org.apache.kafka.common.TopicPartition>>	paused() Retrieves the set of paused topic/partition
io.smallrye.mutiny.Uni<Void>	resume() Resumes the consumption of record.
io.smallrye.mutiny.Uni<Void>	runOnPollingThread(Consumer<org.apache.kafka.clients.consumer.Consumer<K,V>> action) Runs an action on the polling thread.
<R> io.smallrye.mutiny.Uni<R>	runOnPollingThread(Function<org.apache.kafka.clients.consumer.Consumer<K,V>,R> action) Runs an action on the polling thread.
io.smallrye.mutiny.Uni<Void>	seek(org.apache.kafka.common.TopicPartition partition, long offset) Overrides the fetch offset that the consumer will use on the next poll of given topic and partition.
io.smallrye.mutiny.Uni<Void>	seek(org.apache.kafka.common.TopicPartition partition, org.apache.kafka.clients.consumer.OffsetAndMetadata offsetAndMetadata) Overrides the fetch offset that the consumer will use on the next poll of given topic and partition.
io.smallrye.mutiny.Uni<Void>	seekToBeginning(Collection<org.apache.kafka.common.TopicPartition> partitions) Seek to the first offset for each of the given partitions.
io.smallrye.mutiny.Uni<Void>	seekToEnd(Collection<org.apache.kafka.common.TopicPartition> partitions) Seek to the last offset for each of the given partitions.
org.apache.kafka.clients.consumer.Consumer<K,V>	unwrap()

Method Detail

runOnPollingThread

<R> io.smallrye.mutiny.Uni<R> runOnPollingThread(Function<org.apache.kafka.clients.consumer.Consumer<K,V>,R> action)

Runs an action on the polling thread.

The action is a function taking as parameter the Consumer and that returns a result (potentially null). The produced Uni emits the returned result when the action completes. If the action throws an exception, the produced Uni emits the exception as failure.

If the action does not return a result, use runOnPollingThread(java.util.function.Consumer).

Type Parameters:

R - the type of result, can be Void

Parameters:

action - the action to execute, must not be null

Returns:

the Uni emitting the result or the failure when the action completes.

runOnPollingThread

io.smallrye.mutiny.Uni<Void> runOnPollingThread(Consumer<org.apache.kafka.clients.consumer.Consumer<K,V>> action)

Runs an action on the polling thread.

The action is a consumer receiving the Consumer. The produced Uni emits null when the action completes. If the action throws an exception, the produced Uni emits the exception as failure.

Parameters:

action - the action, must not be null

Returns:

the Uni emitting null or the failure when the action completes.

pause

io.smallrye.mutiny.Uni<Set<org.apache.kafka.common.TopicPartition>> pause()

Pauses the consumption of records. The polling will continue, but no records will be received.

Returns:

the Uni emitting when the action completes, the set of topic/partition paused by this call.

paused

io.smallrye.mutiny.Uni<Set<org.apache.kafka.common.TopicPartition>> paused()

Retrieves the set of paused topic/partition

Returns:

the Uni emitting the set of topic/partition paused.

committed

io.smallrye.mutiny.Uni<Map<org.apache.kafka.common.TopicPartition,org.apache.kafka.clients.consumer.OffsetAndMetadata>> committed(org.apache.kafka.common.TopicPartition... tps)

Retrieved the last committed offset for each topic/partition

Parameters:

tps - the set of topic/partition to query, must not be null, must not be empty.

Returns:

the Uni emitting the offset for the underlying consumer for each of the passed topic/partition.

resume

io.smallrye.mutiny.Uni<Void> resume()

Resumes the consumption of record. It resumes the consumption of all the paused topic/partition.

Returns:

the Uni indicating when the resume action completes.

unwrap

org.apache.kafka.clients.consumer.Consumer<K,V> unwrap()

Returns:

the underlying consumer. Be aware that to use it you needs to be on the polling thread.

commit

io.smallrye.mutiny.Uni<Void> commit(Map<org.apache.kafka.common.TopicPartition,org.apache.kafka.clients.consumer.OffsetAndMetadata> map)

Commits the offsets

Parameters:

map - the map of topic/partition -> offset to commit

Returns:

the Uni emitting null when the commit has been executed.

getPositions

io.smallrye.mutiny.Uni<Map<org.apache.kafka.common.TopicPartition,Long>> getPositions()

Retrieves the next positions for each assigned topic/partitions

Returns:

the Uni emitting the map of topic/partition -> position.

getAssignments

io.smallrye.mutiny.Uni<Set<org.apache.kafka.common.TopicPartition>> getAssignments()

Retrieves the current assignments of the consumer.

Returns:

the Uni emitting the set of topic/partition currently assigned to the consumer

seek

io.smallrye.mutiny.Uni<Void> seek(org.apache.kafka.common.TopicPartition partition,
                                  long offset)

Overrides the fetch offset that the consumer will use on the next poll of given topic and partition. Note that you may lose data if this API is arbitrarily used in the middle of consumption.

Parameters:

partition - the topic and partition for which to set the offset

offset - the new offset

Returns:

a Uni that completes successfully when the offset is set; it completes with IllegalArgumentException if the provided offset is negative; it completes with IllegalStateException if the provided TopicPartition is not assigned to this consumer

seek

io.smallrye.mutiny.Uni<Void> seek(org.apache.kafka.common.TopicPartition partition,
                                  org.apache.kafka.clients.consumer.OffsetAndMetadata offsetAndMetadata)

Overrides the fetch offset that the consumer will use on the next poll of given topic and partition. This method allows setting the leaderEpoch along with the desired offset. Note that you may lose data if this API is arbitrarily used in the middle of consumption.

Parameters:

partition - the topic and partition for which to set the offset

offsetAndMetadata - the new offset, with additional metadata

Returns:

a Uni that completes successfully when the offset is set; it completes with IllegalArgumentException if the provided offset is negative; it completes with IllegalStateException if the provided TopicPartition is not assigned to this consumer

seekToBeginning

io.smallrye.mutiny.Uni<Void> seekToBeginning(Collection<org.apache.kafka.common.TopicPartition> partitions)

Seek to the first offset for each of the given partitions. If no partitions are provided, seek to the first offset for all of the currently assigned partitions.

Parameters:

partitions - the partitions for which to set the offset

Returns:

a Uni that completes successfully when the offset is set; it completes with IllegalArgumentException if partitions is null; it completes with IllegalStateException if any of the provided TopicPartitions are not currently assigned to this consumer

seekToEnd

io.smallrye.mutiny.Uni<Void> seekToEnd(Collection<org.apache.kafka.common.TopicPartition> partitions)

Seek to the last offset for each of the given partitions. If no partitions are provided, seek to the last offset for all of the currently assigned partitions.

Parameters:

partitions - the partitions for which to set the offset

Returns:

a Uni that completes successfully when the offset is set; it completes with IllegalArgumentException if partitions is null; it completes with IllegalStateException if any of the provided TopicPartitions are not currently assigned to this consumer