FlinkKafkaPartitioner (Flink : Connectors : Kafka 3.0.2-1.17 API)

java.lang.Object
- org.apache.flink.streaming.connectors.kafka.partitioner.FlinkKafkaPartitioner<T>

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

FlinkFixedPartitioner
```
@PublicEvolving
public abstract class FlinkKafkaPartitioner<T>
extends Object
implements Serializable
```
A FlinkKafkaPartitioner wraps logic on how to partition records across partitions of multiple Kafka topics.

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor Description

FlinkKafkaPartitioner()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`open(int parallelInstanceId, int parallelInstances)`	Initializer for the partitioner.
`abstract int`	`partition(T record, byte[] key, byte[] value, String targetTopic, int[] partitions)`	Determine the id of the partition that the record should be written to.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - FlinkKafkaPartitioner
```
public FlinkKafkaPartitioner()
```
- Method Detail
  - open
```
public void open(int parallelInstanceId,
                 int parallelInstances)
```
    Initializer for the partitioner. This is called once on each parallel sink instance of the Flink Kafka producer. This method should be overridden if necessary.
    
    Parameters:
    
    parallelInstanceId - 0-indexed id of the parallel sink instance in Flink
    
    parallelInstances - the total number of parallel instances
  - partition
```
public abstract int partition(T record,
                              byte[] key,
                              byte[] value,
                              String targetTopic,
                              int[] partitions)
```
    Determine the id of the partition that the record should be written to.
    
    Parameters:
    
    record - the record value
    
    key - serialized key of the record
    
    value - serialized value of the record
    
    targetTopic - target topic for the record
    
    partitions - found partitions for the target topic
    
    Returns:
    
    the id of the target partition