| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.fs; |
| |
| import org.apache.commons.codec.binary.Base64; |
| import org.apache.commons.lang.builder.EqualsBuilder; |
| import org.apache.commons.lang.builder.HashCodeBuilder; |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| /** |
| * HDFS-specific volume identifier which implements {@link VolumeId}. Can be |
| * used to differentiate between the data directories on a single datanode. This |
| * identifier is only unique on a per-datanode basis. |
| * |
| * Note that invalid IDs are represented by {@link VolumeId#INVALID_VOLUME_ID}. |
| */ |
| @InterfaceStability.Unstable |
| @InterfaceAudience.Public |
| public class HdfsVolumeId implements VolumeId { |
| |
| private final byte[] id; |
| |
| public HdfsVolumeId(byte[] id) { |
| if (id == null) { |
| throw new NullPointerException("A valid Id can only be constructed " + |
| "with a non-null byte array."); |
| } |
| this.id = id; |
| } |
| |
| @Override |
| public final boolean isValid() { |
| return true; |
| } |
| |
| @Override |
| public int compareTo(VolumeId arg0) { |
| if (arg0 == null) { |
| return 1; |
| } |
| if (!arg0.isValid()) { |
| // any valid ID is greater |
| // than any invalid ID: |
| return 1; |
| } |
| return hashCode() - arg0.hashCode(); |
| } |
| |
| @Override |
| public int hashCode() { |
| return new HashCodeBuilder().append(id).toHashCode(); |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (obj == null || obj.getClass() != getClass()) { |
| return false; |
| } |
| if (obj == this) { |
| return true; |
| } |
| HdfsVolumeId that = (HdfsVolumeId) obj; |
| // NB: if (!obj.isValid()) { return false; } check is not necessary |
| // because we have class identity checking above, and for this class |
| // isValid() is always true. |
| return new EqualsBuilder().append(this.id, that.id).isEquals(); |
| } |
| |
| @Override |
| public String toString() { |
| return Base64.encodeBase64String(id); |
| } |
| } |