/*
 * The contents of this file are subject to the terms of the Common Development and
 * Distribution License (the License). You may not use this file except in compliance with the
 * License.
 *
 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
 * specific language governing permission and limitations under the License.
 *
 * When distributing Covered Software, include this CDDL Header Notice in each file and include
 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
 * Header, with the fields enclosed by brackets [] replaced by your own identifying
 * information: "Portions Copyright [year] [name of copyright owner]".
 *
 * Copyright 2014-2016 ForgeRock AS.
 */
package org.opends.server.replication.server.changelog.file;

import org.forgerock.opendj.ldap.ByteString;
import org.opends.server.replication.server.changelog.api.ChangelogException;

import java.io.IOException;

/**
 * Parser of a log record.
 * <p>
 * The parser allows to convert from a object to its binary representation
 * and to convert back from the binary representation to the object.
 *
 * @param <K>
 *          Type of the key of the record.
 * @param <V>
 *          Type of the value of the record.
 */
interface RecordParser<K, V>
{
  /**
   * Decode a record from the provided byte array.
   * <p>
   * The record is expected to have been encoded using the {@code writeRecord()}
   * method.
   *
   * @param data
   *          The raw data to read the record from.
   * @return the decoded record, or {@code null} if there is no more record to
   *         read, or only an incomplete record
   * @throws DecodingException
   *           If an error occurs while decoding the record.
   */
  Record<K, V> decodeRecord(ByteString data) throws DecodingException;

  /**
   * Encode the provided record to a byte array.
   * <p>
   * The returned array is intended to be stored as provided in the log file.
   *
   * @param record
   *          The record to encode.
   * @return the bytes array representing the (key,value) record
   */
  ByteString encodeRecord(Record<K, V> record) throws IOException;

  /**
   * Read the key from the provided string.
   *
   * @param key
   *          The string representation of key, suitable for use in a filename,
   *          as written by the {@code encodeKeyToString()} method.
   * @return the key
   * @throws ChangelogException
   *           If key can't be read from the string.
   */
  K decodeKeyFromString(String key) throws ChangelogException;

  /**
   * Returns the provided key as a string that is suitable to be used in a
   * filename.
   *
   * @param key
   *          The key of a record.
   * @return a string encoding the key, unambiguously decodable to the original
   *         key, and suitable for use in a filename. The string should contain
   *         only ASCII characters and no space.
   */
  String encodeKeyToString(K key);

  /**
   * Returns a key that is guaranted to be always higher than any other key.
   *
   * @return the highest possible key
   */
  K getMaxKey();

}