/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.streaming.connectors.kafka.partitioner;
import java.io.Serializable;
/**
* A {@link FlinkKafkaPartitioner} wraps logic on how to partition records
* across partitions of multiple Kafka topics.
*/
public abstract class FlinkKafkaPartitioner<T> implements Serializable {
private static final long serialVersionUID = -9086719227828020494L;
/**
* 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.
*
* @param parallelInstanceId 0-indexed id of the parallel sink instance in Flink
* @param parallelInstances the total number of parallel instances
*/
public void open(int parallelInstanceId, int parallelInstances) {
// overwrite this method if needed.
}
/**
* Determine the id of the partition that the record should be written to.
*
* @param record the record value
* @param key serialized key of the record
* @param value serialized value of the record
* @param targetTopic target topic for the record
* @param partitions found partitions for the target topic
*
* @return the id of the target partition
*/
public abstract int partition(T record, byte[] key, byte[] value, String targetTopic, int[] partitions);
}