content: /*
   * 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;
  
  /**
   * This input stream retrieves {@link JournalEntry} from journal checkpoints and journal logs.
   */
  public interface JournalInputStream extends AutoCloseable {
    /**
     * Reads the next journal entry.
     *
     * @return the next {@link JournalEntry} in the stream, or null if the are no more entries
     */
    JournalEntry read() throws IOException;
  
    /**
     * Closes the stream.
     */
    void close() throws IOException;
  
    /**
     * @return the sequence number of the latest journal entry seen in the stream
     */
    long getLatestSequenceNumber();
  }
  