/*
* 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;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.streaming.connectors.kafka.partitioner.FlinkKafkaPartitioner;
import org.apache.flink.types.Row;
import org.apache.flink.api.java.typeutils.RowTypeInfo;
import org.apache.flink.table.sinks.AppendStreamTableSink;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.util.serialization.SerializationSchema;
import org.apache.flink.util.Preconditions;
import java.util.Properties;
/**
* A version-agnostic Kafka {@link AppendStreamTableSink}.
*
* <p>The version-specific Kafka consumers need to extend this class and
* override {@link #createKafkaProducer(String, Properties, SerializationSchema, FlinkKafkaPartitioner)}}.
*/
public abstract class KafkaTableSink implements AppendStreamTableSink<Row> {
protected final String topic;
protected final Properties properties;
protected SerializationSchema<Row> serializationSchema;
protected final FlinkKafkaPartitioner<Row> partitioner;
protected String[] fieldNames;
protected TypeInformation[] fieldTypes;
/**
* Creates KafkaTableSink
*
* @param topic Kafka topic to write to.
* @param properties Properties for the Kafka consumer.
* @param partitioner Partitioner to select Kafka partition for each item
*/
public KafkaTableSink(
String topic,
Properties properties,
FlinkKafkaPartitioner<Row> partitioner) {
this.topic = Preconditions.checkNotNull(topic, "topic");
this.properties = Preconditions.checkNotNull(properties, "properties");
this.partitioner = Preconditions.checkNotNull(partitioner, "partitioner");
}
/**
* Returns the version-specifid Kafka producer.
*
* @param topic Kafka topic to produce to.
* @param properties Properties for the Kafka producer.
* @param serializationSchema Serialization schema to use to create Kafka records.
* @param partitioner Partitioner to select Kafka partition.
* @return The version-specific Kafka producer
*/
protected abstract FlinkKafkaProducerBase<Row> createKafkaProducer(
String topic, Properties properties,
SerializationSchema<Row> serializationSchema,
FlinkKafkaPartitioner<Row> partitioner);
/**
* Create serialization schema for converting table rows into bytes.
*
* @param fieldNames Field names in table rows.
* @return Instance of serialization schema
*/
protected abstract SerializationSchema<Row> createSerializationSchema(String[] fieldNames);
/**
* Create a deep copy of this sink.
*
* @return Deep copy of this sink
*/
protected abstract KafkaTableSink createCopy();
@Override
public void emitDataStream(DataStream<Row> dataStream) {
FlinkKafkaProducerBase<Row> kafkaProducer = createKafkaProducer(topic, properties, serializationSchema, partitioner);
dataStream.addSink(kafkaProducer);
}
@Override
public TypeInformation<Row> getOutputType() {
return new RowTypeInfo(getFieldTypes());
}
public String[] getFieldNames() {
return fieldNames;
}
@Override
public TypeInformation<?>[] getFieldTypes() {
return fieldTypes;
}
@Override
public KafkaTableSink configure(String[] fieldNames, TypeInformation<?>[] fieldTypes) {
KafkaTableSink copy = createCopy();
copy.fieldNames = Preconditions.checkNotNull(fieldNames, "fieldNames");
copy.fieldTypes = Preconditions.checkNotNull(fieldTypes, "fieldTypes");
Preconditions.checkArgument(fieldNames.length == fieldTypes.length,
"Number of provided field names and types does not match.");
copy.serializationSchema = createSerializationSchema(fieldNames);
return copy;
}
}