Class ConsumerRecord<K,V>

java.lang.Object
org.apache.kafka.clients.consumer.ConsumerRecord<K,V>
public class ConsumerRecord<K,V>extends Object
A key/value pair to be received from Kafka. This also consists of a topic name and a partition number from which the record is being received, an offset that points to the record in a Kafka partition, and a timestamp as marked by the corresponding ProducerRecord.

Thread Safety

This consumer record is not thread-safe. Concurrent access to a ConsumerRecord instance by multiple threads may result in undefined behavior, including but not limited to the following:
  • Throwing ConcurrentModificationException (e.g., when concurrently modifying headers()).
  • Data corruption or logical errors (e.g., inconsistent state of headers or value).
  • Visibility issues (e.g., modifications by one thread not being visible to another thread).

In particular, the headers() method returns a mutable collection of headers. If multiple threads access or modify these headers concurrently, it may lead to race conditions or inconsistent states. It is the responsibility of the user to ensure that multi-threaded access is properly synchronized.

Refer to the KafkaConsumer documentation for more details on multi-threaded consumption and processing strategies.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final long
    NO_TIMESTAMP
     
    static final int
    NULL_SIZE
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    ConsumerRecord(String topic, int partition, long offset, long timestamp, org.apache.kafka.common.record.TimestampType timestampType, int serializedKeySize, int serializedValueSize, K key, V value, Headers headers, Optional<Integer> leaderEpoch)
    Creates a record to be received from a specified topic and partition.
    ConsumerRecord(String topic, int partition, long offset, long timestamp, org.apache.kafka.common.record.TimestampType timestampType, int serializedKeySize, int serializedValueSize, K key, V value, Headers headers, Optional<Integer> leaderEpoch, Optional<Short> deliveryCount)
    Creates a record to be received from a specified topic and partition.
    ConsumerRecord(String topic, int partition, long offset, K key, V value)
    Creates a record to be received from a specified topic and partition (provided for compatibility with Kafka 0.9 before the message format supported timestamps and before serialized metadata were exposed).

  • Method Summary

    Modifier and Type
    Method
    Description
    Optional<Short>
    deliveryCount()
    Get the delivery count for the record if available.
    Headers
    headers()
    The headers (never null)
    K
    key()
    The key (or null if no key is specified)
    Optional<Integer>
    leaderEpoch()
    Get the leader epoch for the record if available
    long
    offset()
    The position of this record in the corresponding Kafka partition.
    int
    partition()
    The partition from which this record is received
    int
    serializedKeySize()
    The size of the serialized, uncompressed key in bytes.
    int
    serializedValueSize()
    The size of the serialized, uncompressed value in bytes.
    long
    timestamp()
    The timestamp of this record, in milliseconds elapsed since unix epoch.
    org.apache.kafka.common.record.TimestampType
    timestampType()
    The timestamp type of this record
    String
    topic()
    The topic this record is received from (never null)
    String
    toString()
     
    V
    value()
    The value

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Field Details

  • Constructor Details

    • ConsumerRecord

      public ConsumerRecord(String topic, int partition, long offset, K key, V value)
      Creates a record to be received from a specified topic and partition (provided for compatibility with Kafka 0.9 before the message format supported timestamps and before serialized metadata were exposed).
      Parameters:
      topic - The topic this record is received from
      partition - The partition of the topic this record is received from
      offset - The offset of this record in the corresponding Kafka partition
      key - The key of the record, if one exists (null is allowed)
      value - The record contents

    • ConsumerRecord

      public ConsumerRecord(String topic, int partition, long offset, long timestamp, org.apache.kafka.common.record.TimestampType timestampType, int serializedKeySize, int serializedValueSize, K key, V value, Headers headers, Optional<Integer> leaderEpoch)
      Creates a record to be received from a specified topic and partition.
      Parameters:
      topic - The topic this record is received from
      partition - The partition of the topic this record is received from
      offset - The offset of this record in the corresponding Kafka partition
      timestamp - The timestamp of the record.
      timestampType - The timestamp type
      serializedKeySize - The length of the serialized key
      serializedValueSize - The length of the serialized value
      key - The key of the record, if one exists (null is allowed)
      value - The record contents
      headers - The headers of the record
      leaderEpoch - Optional leader epoch of the record (may be empty for legacy record formats)

    • ConsumerRecord

      public ConsumerRecord(String topic, int partition, long offset, long timestamp, org.apache.kafka.common.record.TimestampType timestampType, int serializedKeySize, int serializedValueSize, K key, V value, Headers headers, Optional<Integer> leaderEpoch, Optional<Short> deliveryCount)
      Creates a record to be received from a specified topic and partition.
      Parameters:
      topic - The topic this record is received from
      partition - The partition of the topic this record is received from
      offset - The offset of this record in the corresponding Kafka partition
      timestamp - The timestamp of the record.
      timestampType - The timestamp type
      serializedKeySize - The length of the serialized key
      serializedValueSize - The length of the serialized value
      key - The key of the record, if one exists (null is allowed)
      value - The record contents
      headers - The headers of the record
      leaderEpoch - Optional leader epoch of the record (may be empty for legacy record formats)
      deliveryCount - Optional delivery count of the record (may be empty when deliveries not counted)

  • Method Details

    • topic

      public String topic()
      The topic this record is received from (never null)

    • partition

      public int partition()
      The partition from which this record is received

    • headers

      public Headers headers()
      The headers (never null)

    • key

      public K key()
      The key (or null if no key is specified)

    • value

      public V value()
      The value

    • offset

      public long offset()
      The position of this record in the corresponding Kafka partition.

    • timestamp

      public long timestamp()
      The timestamp of this record, in milliseconds elapsed since unix epoch.

    • timestampType

      public org.apache.kafka.common.record.TimestampType timestampType()
      The timestamp type of this record

    • serializedKeySize

      public int serializedKeySize()
      The size of the serialized, uncompressed key in bytes. If key is null, the returned size is -1.

    • serializedValueSize

      public int serializedValueSize()
      The size of the serialized, uncompressed value in bytes. If value is null, the returned size is -1.

    • leaderEpoch

      public Optional<Integer> leaderEpoch()
      Get the leader epoch for the record if available
      Returns:
      the leader epoch or empty for legacy record formats

    • deliveryCount

      public Optional<Short> deliveryCount()
      Get the delivery count for the record if available. Deliveries are counted for records delivered by share groups.
      Returns:
      the delivery count or empty when deliveries not counted

    • toString

      public String toString()
      Overrides:
      toString in class Object