cz.o2.proxima.direct.kafka.ElementSerializer Maven / Gradle / Ivy
/**
* Copyright 2017-2020 O2 Czech Republic, a.s.
*
* Licensed 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 cz.o2.proxima.direct.kafka;
import cz.o2.proxima.repository.EntityDescriptor;
import cz.o2.proxima.storage.StreamElement;
import cz.o2.proxima.util.Pair;
import java.io.Serializable;
import javax.annotation.Nullable;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.common.serialization.Serde;
/**
* A parser that transforms KV from Kafka (byte[], byte[]) into {@link StreamElement}.
*
* @param type of key read from Kafka
* @param type of value read from Kafka
*/
public interface ElementSerializer extends Serializable {
/**
* Life-cycle method called after being instantiated to be able to parameterize itself from the
* given {@link EntityDescriptor}.
*
* @param entityDescriptor the entity that this serializer will be used for
*/
default void setup(EntityDescriptor entityDescriptor) {}
/**
* Parse the raw bytes from Kafka and return a {@link StreamElement}.
*
* @param record a {@link ConsumerRecord} to be parsed
* @param entityDesc descriptor of entity being read
* @return the {@link StreamElement} or null on parse error
*/
@Nullable
StreamElement read(ConsumerRecord record, EntityDescriptor entityDesc);
/**
* Convert {@link StreamElement} into {@link Pair} of key and value.
*
* @param element the {@link StreamElement} to convert
* @return the {@link Pair} of key and value.
*/
Pair write(StreamElement element);
/** Retrieve {@link Serde} for type K. */
Serde keySerde();
/** Retrieve {@link Serde} for type V. */
Serde valueSerde();
}