alluxio-master-2.x/core/server/common/src/main/java/alluxio/master/journal/JournalContext.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.journal;

import alluxio.exception.status.UnavailableException;
import alluxio.proto.journal.Journal.JournalEntry;

import java.io.Closeable;
import java.util.function.Supplier;

/**
 * Context for storing journaling information.
 */
public interface JournalContext extends Closeable, Supplier<JournalContext> {
  /**
   * @param entry the {@link JournalEntry} to append to the journal
   */
  void append(JournalEntry entry);

  /**
   * Flushes all the entries appended by the journal context so far.
   * This method can be called multiple times within the life cycle of the
   * journal context
   * The journals will be committed synchronously (example {@link MasterJournalContext},
   * or only added into the async journal writer (example {@link MetadataSyncMergeJournalContext},
   * based on different implementations.
   */
  void flush() throws UnavailableException;

  @Override
  default JournalContext get() {
    return this;
  }

  @Override
  void close() throws UnavailableException;
}
