1 /**
2 *
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 */
19 package org.apache.hadoop.hbase.mob;
20
21 import org.apache.hadoop.hbase.classification.InterfaceAudience;
22 import org.apache.hadoop.hbase.util.MD5Hash;
23
24 /**
25 * The mob file name.
26 * It consists of a md5 of a start key, a date and an uuid.
27 * It looks like md5(start) + date + uuid.
28 * <ol>
29 * <li>characters 0-31: md5 hex string of a start key. Since the length of the start key is not
30 * fixed, have to use the md5 instead which has a fix length.</li>
31 * <li>characters 32-39: a string of a date with format yyyymmdd. The date is the latest timestamp
32 * of cells in this file</li>
33 * <li>the remaining characters: the uuid.</li>
34 * </ol>
35 * Using md5 hex string of start key as the prefix of file name makes files with the same start
36 * key unique, they're different from the ones with other start keys
37 * The cells come from different regions might be in the same mob file by region split,
38 * this is allowed.
39 * Has the latest timestamp of cells in the file name in order to clean the expired mob files by
40 * TTL easily. If this timestamp is older than the TTL, it's regarded as expired.
41 */
42 @InterfaceAudience.Private
43 public final class MobFileName {
44
45 private final String date;
46 private final String startKey;
47 private final String uuid;
48 private final String fileName;
49
50 /**
51 * @param startKey
52 * The start key.
53 * @param date
54 * The string of the latest timestamp of cells in this file, the format is yyyymmdd.
55 * @param uuid
56 * The uuid
57 */
58 private MobFileName(byte[] startKey, String date, String uuid) {
59 this.startKey = MD5Hash.getMD5AsHex(startKey, 0, startKey.length);
60 this.uuid = uuid;
61 this.date = date;
62 this.fileName = this.startKey + date + uuid;
63 }
64
65 /**
66 * @param startKey
67 * The md5 hex string of the start key.
68 * @param date
69 * The string of the latest timestamp of cells in this file, the format is yyyymmdd.
70 * @param uuid
71 * The uuid
72 */
73 private MobFileName(String startKey, String date, String uuid) {
74 this.startKey = startKey;
75 this.uuid = uuid;
76 this.date = date;
77 this.fileName = this.startKey + date + uuid;
78 }
79
80 /**
81 * Creates an instance of MobFileName
82 *
83 * @param startKey
84 * The start key.
85 * @param date
86 * The string of the latest timestamp of cells in this file, the format is yyyymmdd.
87 * @param uuid The uuid.
88 * @return An instance of a MobFileName.
89 */
90 public static MobFileName create(byte[] startKey, String date, String uuid) {
91 return new MobFileName(startKey, date, uuid);
92 }
93
94 /**
95 * Creates an instance of MobFileName
96 *
97 * @param startKey
98 * The md5 hex string of the start key.
99 * @param date
100 * The string of the latest timestamp of cells in this file, the format is yyyymmdd.
101 * @param uuid The uuid.
102 * @return An instance of a MobFileName.
103 */
104 public static MobFileName create(String startKey, String date, String uuid) {
105 return new MobFileName(startKey, date, uuid);
106 }
107
108 /**
109 * Creates an instance of MobFileName.
110 * @param fileName The string format of a file name.
111 * @return An instance of a MobFileName.
112 */
113 public static MobFileName create(String fileName) {
114 // The format of a file name is md5HexString(0-31bytes) + date(32-39bytes) + UUID
115 // The date format is yyyyMMdd
116 String startKey = fileName.substring(0, 32);
117 String date = fileName.substring(32, 40);
118 String uuid = fileName.substring(40);
119 return new MobFileName(startKey, date, uuid);
120 }
121
122 /**
123 * Gets the hex string of the md5 for a start key.
124 * @return The hex string of the md5 for a start key.
125 */
126 public String getStartKey() {
127 return startKey;
128 }
129
130 /**
131 * Gets the date string. Its format is yyyymmdd.
132 * @return The date string.
133 */
134 public String getDate() {
135 return this.date;
136 }
137
138 @Override
139 public int hashCode() {
140 StringBuilder builder = new StringBuilder();
141 builder.append(startKey);
142 builder.append(date);
143 builder.append(uuid);
144 return builder.toString().hashCode();
145 }
146
147 @Override
148 public boolean equals(Object anObject) {
149 if (this == anObject) {
150 return true;
151 }
152 if (anObject instanceof MobFileName) {
153 MobFileName another = (MobFileName) anObject;
154 if (this.startKey.equals(another.startKey) && this.date.equals(another.date)
155 && this.uuid.equals(another.uuid)) {
156 return true;
157 }
158 }
159 return false;
160 }
161
162 /**
163 * Gets the file name.
164 * @return The file name.
165 */
166 public String getFileName() {
167 return this.fileName;
168 }
169 }