branch-0.23.1/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineEditsViewer/BinaryTokenizer.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hdfs.tools.offlineEditsViewer;

import java.io.FileInputStream;
import java.io.DataInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;

/**
 * Tokenizer that reads tokens from a binary file
 *
 */
@InterfaceAudience.Private
@InterfaceStability.Unstable
public class BinaryTokenizer implements Tokenizer {

  private DataInputStream in;

  /**
   * BinaryTokenizer constructor
   *
   * @param filename input filename
   */
  public BinaryTokenizer(String filename) throws FileNotFoundException {
    in = new DataInputStream(new FileInputStream(filename));
  }

  /**
   * BinaryTokenizer constructor
   *
   * @param in input stream
   */
  public BinaryTokenizer(DataInputStream in) throws IOException {
    this.in = in;
  }

  /**
   * @see org.apache.hadoop.hdfs.tools.offlineEditsViewer.Tokenizer#read
   *
   * @param t a Token to read
   * @return token that was just read
   */
  @Override
  public Token read(Token t) throws IOException {
    t.fromBinary(in);
    return t;
  }
}