org.apache.kafka.clients.producer.ProducerRecord Maven / Gradle / Ivy
/*
* 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.kafka.clients.producer;
import org.apache.kafka.common.header.Header;
import org.apache.kafka.common.header.Headers;
import org.apache.kafka.common.header.internals.RecordHeaders;
import java.util.Objects;
/**
* A key/value pair to be sent to Kafka. This consists of a topic name to which the record is being sent, an optional
* partition number, and an optional key and value.
*
* If a valid partition number is specified that partition will be used when sending the record. If no partition is
* specified but a key is present a partition will be chosen using a hash of the key. If neither key nor partition is
* present a partition will be assigned in a round-robin fashion.
*
* The record also has an associated timestamp. If the user did not provide a timestamp, the producer will stamp the
* record with its current time. The timestamp eventually used by Kafka depends on the timestamp type configured for
* the topic.
*
* If the topic is configured to use {@link org.apache.kafka.common.record.TimestampType#CREATE_TIME CreateTime},
* the timestamp in the producer record will be used by the broker.
*
*
* If the topic is configured to use {@link org.apache.kafka.common.record.TimestampType#LOG_APPEND_TIME LogAppendTime},
* the timestamp in the producer record will be overwritten by the broker with the broker local time when it appends the
* message to its log.
*
*
* In either of the cases above, the timestamp that has actually been used will be returned to user in
* {@link RecordMetadata}
*/
public class ProducerRecord {
private final String topic;
private final Integer partition;
private final Headers headers;
private final K key;
private final V value;
private final Long timestamp;
/**
* Creates a record with a specified timestamp to be sent to a specified topic and partition
*
* @param topic The topic the record will be appended to
* @param partition The partition to which the record should be sent
* @param timestamp The timestamp of the record, in milliseconds since epoch. If null, the producer will assign
* the timestamp using System.currentTimeMillis().
* @param key The key that will be included in the record
* @param value The record contents
* @param headers the headers that will be included in the record
*/
public ProducerRecord(String topic, Integer partition, Long timestamp, K key, V value, Iterable headers) {
if (topic == null)
throw new IllegalArgumentException("Topic cannot be null.");
if (timestamp != null && timestamp < 0)
throw new IllegalArgumentException(
String.format("Invalid timestamp: %d. Timestamp should always be non-negative or null.", timestamp));
if (partition != null && partition < 0)
throw new IllegalArgumentException(
String.format("Invalid partition: %d. Partition number should always be non-negative or null.", partition));
this.topic = topic;
this.partition = partition;
this.key = key;
this.value = value;
this.timestamp = timestamp;
this.headers = new RecordHeaders(headers);
}
/**
* Creates a record with a specified timestamp to be sent to a specified topic and partition
*
* @param topic The topic the record will be appended to
* @param partition The partition to which the record should be sent
* @param timestamp The timestamp of the record, in milliseconds since epoch. If null, the producer will assign the
* timestamp using System.currentTimeMillis().
* @param key The key that will be included in the record
* @param value The record contents
*/
public ProducerRecord(String topic, Integer partition, Long timestamp, K key, V value) {
this(topic, partition, timestamp, key, value, null);
}
/**
* Creates a record to be sent to a specified topic and partition
*
* @param topic The topic the record will be appended to
* @param partition The partition to which the record should be sent
* @param key The key that will be included in the record
* @param value The record contents
* @param headers The headers that will be included in the record
*/
public ProducerRecord(String topic, Integer partition, K key, V value, Iterable headers) {
this(topic, partition, null, key, value, headers);
}
/**
* Creates a record to be sent to a specified topic and partition
*
* @param topic The topic the record will be appended to
* @param partition The partition to which the record should be sent
* @param key The key that will be included in the record
* @param value The record contents
*/
public ProducerRecord(String topic, Integer partition, K key, V value) {
this(topic, partition, null, key, value, null);
}
/**
* Create a record to be sent to Kafka
*
* @param topic The topic the record will be appended to
* @param key The key that will be included in the record
* @param value The record contents
*/
public ProducerRecord(String topic, K key, V value) {
this(topic, null, null, key, value, null);
}
/**
* Create a record with no key
*
* @param topic The topic this record should be sent to
* @param value The record contents
*/
public ProducerRecord(String topic, V value) {
this(topic, null, null, null, value, null);
}
/**
* @return The topic this record is being sent to
*/
public String topic() {
return topic;
}
/**
* @return The headers
*/
public Headers headers() {
return headers;
}
/**
* @return The key (or null if no key is specified)
*/
public K key() {
return key;
}
/**
* @return The value
*/
public V value() {
return value;
}
/**
* @return The timestamp, which is in milliseconds since epoch.
*/
public Long timestamp() {
return timestamp;
}
/**
* @return The partition to which the record will be sent (or null if no partition was specified)
*/
public Integer partition() {
return partition;
}
@Override
public String toString() {
String headers = this.headers == null ? "null" : this.headers.toString();
String key = this.key == null ? "null" : this.key.toString();
String value = this.value == null ? "null" : this.value.toString();
String timestamp = this.timestamp == null ? "null" : this.timestamp.toString();
return "ProducerRecord(topic=" + topic + ", partition=" + partition + ", headers=" + headers + ", key=" + key + ", value=" + value +
", timestamp=" + timestamp + ")";
}
@Override
public boolean equals(Object o) {
if (this == o)
return true;
else if (!(o instanceof ProducerRecord))
return false;
ProducerRecord that = (ProducerRecord) o;
return Objects.equals(key, that.key) &&
Objects.equals(partition, that.partition) &&
Objects.equals(topic, that.topic) &&
Objects.equals(headers, that.headers) &&
Objects.equals(value, that.value) &&
Objects.equals(timestamp, that.timestamp);
}
@Override
public int hashCode() {
int result = topic != null ? topic.hashCode() : 0;
result = 31 * result + (partition != null ? partition.hashCode() : 0);
result = 31 * result + (headers != null ? headers.hashCode() : 0);
result = 31 * result + (key != null ? key.hashCode() : 0);
result = 31 * result + (value != null ? value.hashCode() : 0);
result = 31 * result + (timestamp != null ? timestamp.hashCode() : 0);
return result;
}
}