001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.fs;
019
020import java.util.Arrays;
021
022import org.apache.hadoop.classification.InterfaceAudience;
023import org.apache.hadoop.classification.InterfaceStability;
024import org.apache.hadoop.fs.Options.ChecksumOpt;
025import org.apache.hadoop.io.Writable;
026
027/** An abstract class representing file checksums for files. */
028@InterfaceAudience.Public
029@InterfaceStability.Stable
030public abstract class FileChecksum implements Writable {
031  /** The checksum algorithm name */
032  public abstract String getAlgorithmName();
033
034  /** The length of the checksum in bytes */
035  public abstract int getLength();
036
037  /** The value of the checksum in bytes */
038  public abstract byte[] getBytes();
039
040  public ChecksumOpt getChecksumOpt() {
041    return null;
042  }
043
044  /** Return true if both the algorithms and the values are the same. */
045  @Override
046  public boolean equals(Object other) {
047    if (other == this) {
048      return true;
049    }
050    if (other == null || !(other instanceof FileChecksum)) {
051      return false;
052    }
053
054    final FileChecksum that = (FileChecksum)other;
055    return this.getAlgorithmName().equals(that.getAlgorithmName())
056      && Arrays.equals(this.getBytes(), that.getBytes());
057  }
058
059  @Override
060  public int hashCode() {
061    return getAlgorithmName().hashCode() ^ Arrays.hashCode(getBytes());
062  }
063}