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.checkpoint;
  
  import com.google.common.base.Preconditions;
  
  import java.io.IOException;
  import java.io.PrintStream;
  
  /**
   * Format for checkpoints containing a single long.
   */
  public class LongCheckpointFormat implements CheckpointFormat {
    @Override
    public LongCheckpointReader createReader(CheckpointInputStream in) {
      return new LongCheckpointReader(in);
    }
  
    @Override
    public void parseToHumanReadable(CheckpointInputStream in, PrintStream out) throws IOException {
      LongCheckpointReader reader = createReader(in);
      out.println(reader.getLong());
    }
  
    /**
     * Reads a checkpoint containing a single long.
     */
    public static class LongCheckpointReader implements CheckpointReader {
      private final CheckpointInputStream mStream;
  
      /**
       * @param in the checkpoint stream to read from
       */
      public LongCheckpointReader(CheckpointInputStream in) {
        Preconditions.checkState(in.getType() == CheckpointType.LONG,
            "Unexpected checkpoint type: %s", in.getType());
        mStream = in;
      }
  
      /**
       * @return the long in the checkpoint
       */
      public Long getLong() throws IOException {
        return mStream.readLong();
      }
    }
  }
  