org.springframework.kafka.support.SimpleKafkaHeaderMapper Maven / Gradle / Ivy
/*
* Copyright 2018-2019 the original author or authors.
*
* 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
*
* https://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.springframework.kafka.support;
import java.nio.ByteBuffer;
import java.util.Map;
import org.apache.kafka.common.header.Headers;
import org.apache.kafka.common.header.internals.RecordHeader;
import org.springframework.messaging.MessageHeaders;
/**
* A simple header mapper that maps headers directly; for outbound,
* only byte[] headers are mapped; for inbound, headers are mapped
* unchanged, as byte[]. Strings can also be mapped to/from byte.
* See {@link #setRawMappedHeaders(Map)}.
* Most headers in {@link KafkaHeaders} are not mapped on outbound messages.
* The exceptions are correlation and reply headers for request/reply
*
* @author Gary Russell
* @since 2.1.3
*
*/
public class SimpleKafkaHeaderMapper extends AbstractKafkaHeaderMapper {
/**
* Construct an instance with the default object mapper and default header patterns
* for outbound headers; all inbound headers are mapped. The default pattern list is
* {@code "!id", "!timestamp" and "*"}. In addition, most of the headers in
* {@link KafkaHeaders} are never mapped as headers since they represent data in
* consumer/producer records.
*/
public SimpleKafkaHeaderMapper() {
super("!" + MessageHeaders.ID,
"!" + MessageHeaders.TIMESTAMP,
"*");
}
/**
* Construct an instance with a default object mapper and the provided header patterns
* for outbound headers; all inbound headers are mapped. The patterns are applied in
* order, stopping on the first match (positive or negative). Patterns are negated by
* preceding them with "!". The patterns will replace the default patterns; you
* generally should not map the {@code "id" and "timestamp"} headers. Note:
* most of the headers in {@link KafkaHeaders} are never mapped as headers since they
* represent data in consumer/producer records.
* @param patterns the patterns.
* @see org.springframework.util.PatternMatchUtils#simpleMatch(String, String)
*/
public SimpleKafkaHeaderMapper(String... patterns) {
super(patterns);
}
@Override
public void fromHeaders(MessageHeaders headers, Headers target) {
headers.forEach((key, value) -> {
if (!key.equals(KafkaHeaders.DELIVERY_ATTEMPT)) {
Object valueToAdd = headerValueToAddOut(key, value);
if (valueToAdd instanceof byte[] && matches(key, valueToAdd)) {
target.add(new RecordHeader(key, (byte[]) valueToAdd));
}
}
});
}
@Override
public void toHeaders(Headers source, Map target) {
source.forEach(header -> {
if (header.key().equals(KafkaHeaders.DELIVERY_ATTEMPT)) {
target.put(header.key(), ByteBuffer.wrap(header.value()).getInt());
}
else {
target.put(header.key(), headerValueToAddIn(header));
}
});
}
}