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.commons.lang.builder.EqualsBuilder; 021 import org.apache.commons.lang.builder.HashCodeBuilder; 022 import org.apache.hadoop.classification.InterfaceAudience; 023 import org.apache.hadoop.classification.InterfaceStability; 024 025 /** 026 * HDFS-specific volume identifier which implements {@link VolumeId}. Can be 027 * used to differentiate between the data directories on a single datanode. This 028 * identifier is only unique on a per-datanode basis. 029 */ 030 @InterfaceStability.Unstable 031 @InterfaceAudience.Public 032 public class HdfsVolumeId implements VolumeId { 033 034 private final byte id; 035 private final boolean isValid; 036 037 public HdfsVolumeId(byte id, boolean isValid) { 038 this.id = id; 039 this.isValid = isValid; 040 } 041 042 @Override 043 public boolean isValid() { 044 return isValid; 045 } 046 047 @Override 048 public int compareTo(VolumeId arg0) { 049 return hashCode() - arg0.hashCode(); 050 } 051 052 @Override 053 public int hashCode() { 054 return new HashCodeBuilder().append(id).toHashCode(); 055 } 056 057 @Override 058 public boolean equals(Object obj) { 059 if (obj == null || obj.getClass() != getClass()) { 060 return false; 061 } 062 if (obj == this) { 063 return true; 064 } 065 066 HdfsVolumeId that = (HdfsVolumeId) obj; 067 return new EqualsBuilder().append(this.id, that.id).isEquals(); 068 } 069 070 @Override 071 public String toString() { 072 return Byte.toString(id); 073 } 074 }