org.apache.kafka.connect.header.Header 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.connect.header;
import org.apache.kafka.connect.data.Schema;
/**
* A {@link Header} is a key-value pair, and multiple headers can be included with the key, value, and timestamp in each Kafka message.
* If the value contains schema information, then the header will have a non-null {@link #schema() schema}.
*
* This is an immutable interface.
*/
public interface Header {
/**
* The header's key, which is not necessarily unique within the set of headers on a Kafka message.
*
* @return the header's key; never null
*/
String key();
/**
* Return the {@link Schema} associated with this header, if there is one. Not all headers will have schemas.
*
* @return the header's schema, or null if no schema is associated with this header
*/
Schema schema();
/**
* Get the header's value as deserialized by Connect's header converter.
*
* @return the deserialized object representation of the header's value; may be null
*/
Object value();
/**
* Return a new {@link Header} object that has the same key but with the supplied value.
*
* @param schema the schema for the new value; may be null
* @param value the new value
* @return the new {@link Header}; never null
*/
Header with(Schema schema, Object value);
/**
* Return a new {@link Header} object that has the same schema and value but with the supplied key.
*
* @param key the key for the new header; may not be null
* @return the new {@link Header}; never null
*/
Header rename(String key);
}