alluxio-master-2.x/core/server/common/src/main/java/alluxio/master/journalv0/JournalFormatter.java
/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the "License"). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio.master.journalv0;

import alluxio.proto.journal.Journal.JournalEntry;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * This describes the interface for serializing and de-serializing entries in the journal.
 */
public interface JournalFormatter {

  /**
   * Factory for {@link JournalFormatter}.
   */
  class Factory {

    private Factory() {} // prevent instantiation

    /**
     * Factory method for {@link JournalFormatter}.
     *
     * @return the created formatter
     */
    public static JournalFormatter create() {
      return new ProtoBufJournalFormatter();
    }
  }

  /**
   * Serializes the given entry and writes it to the given output stream.
   *
   * @param entry The journal entry to serialize
   * @param outputStream the output stream to serialize the entry to
   */
  void serialize(JournalEntry entry, OutputStream outputStream) throws IOException;

  /**
   * Returns a {@link JournalInputStream} from the given input stream. The returned input stream
   * produces a stream of {@link JournalEntry} objects.
   *
   * @param inputStream The input stream to deserialize
   * @return a {@link JournalInputStream} for reading all the journal entries in the given input
   *         stream.
   */
  JournalInputStream deserialize(InputStream inputStream) throws IOException;
}
