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     */
018    package org.apache.hadoop.fs;
019    
020    import java.util.Arrays;
021    
022    import org.apache.hadoop.classification.InterfaceAudience;
023    import org.apache.hadoop.classification.InterfaceStability;
024    import org.apache.hadoop.io.Writable;
025    
026    /** An abstract class representing file checksums for files. */
027    @InterfaceAudience.Public
028    @InterfaceStability.Stable
029    public abstract class FileChecksum implements Writable {
030      /** The checksum algorithm name */ 
031      public abstract String getAlgorithmName();
032    
033      /** The length of the checksum in bytes */ 
034      public abstract int getLength();
035    
036      /** The value of the checksum in bytes */ 
037      public abstract byte[] getBytes();
038    
039      /** Return true if both the algorithms and the values are the same. */
040      @Override
041      public boolean equals(Object other) {
042        if (other == this) {
043          return true;
044        }
045        if (other == null || !(other instanceof FileChecksum)) {
046          return false;
047        }
048    
049        final FileChecksum that = (FileChecksum)other;
050        return this.getAlgorithmName().equals(that.getAlgorithmName())
051          && Arrays.equals(this.getBytes(), that.getBytes());
052      }
053      
054      @Override
055      public int hashCode() {
056        return getAlgorithmName().hashCode() ^ Arrays.hashCode(getBytes());
057      }
058    }