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.journal;
  
  import alluxio.master.journal.checkpoint.CheckpointInputStream;
  import alluxio.master.journal.checkpoint.CheckpointName;
  import alluxio.proto.journal.Journal.JournalEntry;
  import alluxio.resource.CloseableIterator;
  import alluxio.util.StreamUtils;
  
  import com.google.common.collect.Lists;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.util.List;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.ExecutorService;
  
  /**
   * Convenience class which groups together multiple Journaled components as a single Journaled
   * component.
   */
  public class JournaledGroup implements Journaled {
    private final List<Journaled> mJournaled;
    private final CheckpointName mCheckpointName;
  
    /**
     * Creates an instance of a single journaled component, from a list of journaled components.
     *
     * @param journaled the list of journaled components to be grouped
     * @param checkpointName the name of the journal checkpoint for the group
     */
    public JournaledGroup(List<Journaled> journaled, CheckpointName checkpointName) {
      mJournaled = journaled;
      mCheckpointName = checkpointName;
    }
  
    /**
     * @return the list of journaled components in this group
     */
    public List<Journaled> getJournaled() {
      return mJournaled;
    }
  
    @Override
    public boolean processJournalEntry(JournalEntry entry) {
      for (Journaled journaled : mJournaled) {
        if (journaled.processJournalEntry(entry)) {
          return true;
        }
      }
      return false;
    }
  
    @Override
    public void resetState() {
      // resetState in the reverse order that we replay the journal
      Lists.reverse(mJournaled).forEach(Journaled::resetState);
    }
  
    @Override
    public CheckpointName getCheckpointName() {
      return mCheckpointName;
    }
  
    @Override
    public CompletableFuture<Void> writeToCheckpoint(File directory,
                                                     ExecutorService executorService) {
      return CompletableFuture.allOf(mJournaled.stream()
              .map(journaled -> journaled.writeToCheckpoint(directory, executorService))
              .toArray(CompletableFuture[]::new));
    }
  
    @Override
    public void writeToCheckpoint(OutputStream output) throws IOException, InterruptedException {
      JournalUtils.writeToCheckpoint(output, mJournaled);
    }
  
    @Override
    public CompletableFuture<Void> restoreFromCheckpoint(File directory,
                                                         ExecutorService executorService) {
      return CompletableFuture.allOf(mJournaled.stream()
              .map(journaled -> journaled.restoreFromCheckpoint(directory, executorService))
              .toArray(CompletableFuture[]::new));
    }
  
    @Override
    public void restoreFromCheckpoint(CheckpointInputStream input) throws IOException {
      JournalUtils.restoreFromCheckpoint(input, mJournaled);
    }
  
    @Override
    public CloseableIterator<JournalEntry> getJournalEntryIterator() {
      List<CloseableIterator<JournalEntry>> componentIters = StreamUtils
          .map(JournalEntryIterable::getJournalEntryIterator, mJournaled);
      return CloseableIterator.concat(componentIters);
    }
  }
  