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 org.apache.hadoop.classification.InterfaceAudience;
021    import org.apache.hadoop.classification.InterfaceStability;
022    
023    /**
024     * Opaque interface that identifies a disk location. Subclasses
025     * should implement {@link Comparable} and override both equals and hashCode.
026     */
027    @InterfaceStability.Unstable
028    @InterfaceAudience.Public
029    public interface VolumeId extends Comparable<VolumeId> {
030    
031      @Override
032      abstract public int compareTo(VolumeId arg0);
033    
034      @Override
035      abstract public int hashCode();
036    
037      @Override
038      abstract public boolean equals(Object obj);
039    
040    }