# Class: KafkaConsumer

## vertx-kafka-client-js/kafka_consumer~ KafkaConsumer

#### new KafkaConsumer()

Vert.x Kafka consumer.

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 37

### Methods

#### assign(topicPartitions, completionHandler) → {KafkaConsumer}

Manually assign a list of partition to this consumer.

##### Parameters:

Name | Type | Description
--- | --- | ---
`topicPartitions` | Array.<Object> | partitions which want assigned
`completionHandler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 216

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### assignment(handler) → {KafkaConsumer}

Get the set of partitions currently assigned to this consumer.

##### Parameters:

Name | Type | Description
--- | --- | ---
`handler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 252

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### batchHandler(handler) → {KafkaConsumer}

Set the handler to be used when batches of messages are fetched from the Kafka server. Batch handlers need to take care not to block the event loop when dealing with large batches. It is better to process records individually using the [#handler(Handler) record handler] KafkaConsumer.

##### Parameters:

Name | Type | Description
--- | --- | ---
`handler` | function | handler called when batches of messages are fetched

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 537

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### beginningOffsets(topicPartition, handler)

Get the first offset for the given partitions.

##### Parameters:

Name | Type | Description
--- | --- | ---
`topicPartition` | Object | the partition to get the earliest offset.
`handler` | function | handler called on operation completed. Returns the earliest available offset for the given partition

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 617

#### close(completionHandler)

Close the consumer

##### Parameters:

Name | Type | Description
--- | --- | ---
`completionHandler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 553

#### commit(completionHandler)

Commit current offsets for all the subscribed list of topics and partition.

##### Parameters:

Name | Type | Description
--- | --- | ---
`completionHandler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 470

#### committed(topicPartition, handler)

Get the last committed offset for the given partition (whether the commit happened by this process or another).

##### Parameters:

Name | Type | Description
--- | --- | ---
`topicPartition` | Object | topic partition for getting last committed offset
`handler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 492

#### endHandler(endHandler) → {KafkaConsumer}

##### Parameters:

Name | Type | Description
--- | --- | ---
`endHandler` | function |

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 163

##### Returns:

Type
  KafkaConsumer

#### endOffsets(topicPartition, handler)

Get the last offset for the given partition. The last offset of a partition is the offset of the upcoming message, i.e. the offset of the last available message + 1.

##### Parameters:

Name | Type | Description
--- | --- | ---
`topicPartition` | Object | the partition to get the end offset.
`handler` | function | handler called on operation completed. The end offset for the given partition.

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 638

#### exceptionHandler(handler) → {KafkaConsumer}

##### Parameters:

Name | Type | Description
--- | --- | ---
`handler` | function |

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 51

##### Returns:

Type
  KafkaConsumer

#### handler(handler) → {KafkaConsumer}

##### Parameters:

Name | Type | Description
--- | --- | ---
`handler` | function |

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 67

##### Returns:

Type
  KafkaConsumer

#### offsetsForTimes(topicPartition, timestamp, handler)

Look up the offset for the given partition by timestamp. Note: the result might be null in case for the given timestamp no offset can be found -- e.g., when the timestamp refers to the future

##### Parameters:

Name | Type | Description
--- | --- | ---
`topicPartition` | Object | TopicPartition to query.
`timestamp` | number | Timestamp to be used in the query.
`handler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 597

#### partitionsAssignedHandler(handler) → {KafkaConsumer}

Set the handler called when topic partitions are assigned to the consumer

##### Parameters:

Name | Type | Description
--- | --- | ---
`handler` | function | handler called on assigned topic partitions

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 354

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### partitionsFor(topic, handler) → {KafkaConsumer}

Get metadata about the partitions for a given topic.

##### Parameters:

Name | Type | Description
--- | --- | ---
`topic` | string | topic partition for which getting partitions info
`handler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 513

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### partitionsRevokedHandler(handler) → {KafkaConsumer}

Set the handler called when topic partitions are revoked to the consumer

##### Parameters:

Name | Type | Description
--- | --- | ---
`handler` | function | handler called on revoked topic partitions

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 337

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### pause(topicPartitions, completionHandler) → {KafkaConsumer}

Suspend fetching from the requested partitions.

##### Parameters:

Name | Type | Description
--- | --- | ---
`topicPartitions` | Array.<Object> | topic partition from which suspend fetching
`completionHandler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 85

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### paused(handler)

Get the set of partitions that were previously paused by a call to pause(Set).

##### Parameters:

Name | Type | Description
--- | --- | ---
`handler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 317

#### position(partition, handler)

Get the offset of the next record that will be fetched (if a record with that offset exists).

##### Parameters:

Name | Type | Description
--- | --- | ---
`partition` | Object | The partition to get the position for
`handler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 575

#### resume(topicPartitions, completionHandler) → {KafkaConsumer}

Resume specified partitions which have been paused with pause.

##### Parameters:

Name | Type | Description
--- | --- | ---
`topicPartitions` | Array.<Object> | topic partition from which resume fetching
`completionHandler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 125

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### seek(topicPartition, offset, completionHandler) → {KafkaConsumer}

Overrides the fetch offsets that the consumer will use on the next poll.

##### Parameters:

Name | Type | Description
--- | --- | ---
`topicPartition` | Object | topic partition for which seek
`offset` | number | offset to seek inside the topic partition
`completionHandler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 373

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### seekToBeginning(topicPartitions, completionHandler) → {KafkaConsumer}

Seek to the first offset for each of the given partitions.

##### Parameters:

Name | Type | Description
--- | --- | ---
`topicPartitions` | Array.<Object> | topic partition for which seek
`completionHandler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 398

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### seekToEnd(topicPartitions, completionHandler) → {KafkaConsumer}

Seek to the last offset for each of the given partitions.

##### Parameters:

Name | Type | Description
--- | --- | ---
`topicPartitions` | Array.<Object> | topic partition for which seek
`completionHandler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 435

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### subscribe(topics, completionHandler) → {KafkaConsumer}

Subscribe to the given list of topics to get dynamically assigned partitions.

##### Parameters:

Name | Type | Description
--- | --- | ---
`topics` | Array.<string> | topics to subscribe to
`completionHandler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 179

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### subscription(handler) → {KafkaConsumer}

Get the current subscription.

##### Parameters:

Name | Type | Description
--- | --- | ---
`handler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 297

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer

#### unsubscribe(completionHandler) → {KafkaConsumer}

Unsubscribe from topics currently subscribed with subscribe.

##### Parameters:

Name | Type | Description
--- | --- | ---
`completionHandler` | function | handler called on operation completed

Source:
  - vertx-kafka-client-js/kafka_consumer.js, line 273

##### Returns:

current KafkaConsumer instance

Type
  KafkaConsumer