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 org.apache.commons.lang.builder.EqualsBuilder; 021import org.apache.commons.lang.builder.HashCodeBuilder; 022import org.apache.hadoop.classification.InterfaceAudience; 023import org.apache.hadoop.classification.InterfaceStability; 024import org.apache.hadoop.util.StringUtils; 025 026import com.google.common.base.Preconditions; 027 028/** 029 * HDFS-specific volume identifier which implements {@link VolumeId}. Can be 030 * used to differentiate between the data directories on a single datanode. This 031 * identifier is only unique on a per-datanode basis. 032 */ 033@InterfaceStability.Unstable 034@InterfaceAudience.Public 035public class HdfsVolumeId implements VolumeId { 036 037 private final byte[] id; 038 039 public HdfsVolumeId(byte[] id) { 040 Preconditions.checkNotNull(id, "id cannot be null"); 041 this.id = id; 042 } 043 044 @Override 045 public int compareTo(VolumeId arg0) { 046 if (arg0 == null) { 047 return 1; 048 } 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 HdfsVolumeId that = (HdfsVolumeId) obj; 066 return new EqualsBuilder().append(this.id, that.id).isEquals(); 067 } 068 069 @Override 070 public String toString() { 071 return StringUtils.byteToHexString(id); 072 } 073}