io.telicent.smart.cache.sources.kafka.serializers.AbstractRdfSerdes Maven / Gradle / Ivy
/**
* Copyright (C) Telicent Ltd
*
* 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 io.telicent.smart.cache.sources.kafka.serializers;
import org.apache.jena.riot.Lang;
import org.apache.jena.riot.web.HttpNames;
import org.apache.kafka.common.header.Header;
import org.apache.kafka.common.header.Headers;
import java.nio.charset.StandardCharsets;
/**
* Abstract base class for RDF serializers and deserializers
*/
public class AbstractRdfSerdes {
/**
* The default RDF language to use for (de)serialization if an event doesn't declare a specific language via its
* content type header
*/
protected final Lang defaultLang;
/**
* Creates a new serdes
*
* @param defaultLang Default RDF language to use
*/
public AbstractRdfSerdes(Lang defaultLang) {
this.defaultLang = defaultLang;
}
/**
* Gets the configured default RDF language for the serdes
*
* @return Default RDF Language
*/
Lang getDefaultLang() {
return this.defaultLang;
}
/**
* Finds the value of the first Content Type header (if any)
*
* @param headers Kafka headers
* @return Content Type, or {@code null} if no such header
*/
protected String findContentType(Headers headers) {
if (headers == null) {
return null;
}
Header header = headers.lastHeader(HttpNames.hContentType);
return header != null ? new String(header.value(), StandardCharsets.UTF_8) : null;
}
}