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package org.apache.kafka.common;

import java.io.PrintStream;
import java.util.Properties;

import org.apache.kafka.clients.consumer.ConsumerRecord;

/**
 * This interface allows to define Formatters that can be used to parse and format records read by a
 *  Consumer instance for display.
 * The kafka-console-consumer has built-in support for MessageFormatter, via the --formatter flag.
 * 
 * Kafka provides a few implementations to display records of internal topics such as __consumer_offsets, 
 * __transaction_state and the MirrorMaker2 topics.
 * @author mickael
 *
 */
public interface MessageFormatter {

    /**
     * Initializes the MessageFormatter
     * @param props Properties to configure the formatter
     */
    default public void init(Properties props) {}

    /**
     * Parses and formats a record for display
     * @param consumerRecord the record to format
     * @param output the print stream used to display the record
     */
    public void writeTo(ConsumerRecord<byte[], byte[]> consumerRecord, PrintStream output);

    /**
     * Closes the formatter
     */
    default public void close() {}
}