/**
*
* 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.hbase.mob;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.util.MD5Hash;
/**
* The mob file name.
* It consists of a md5 of a start key, a date and an uuid.
* It looks like md5(start) + date + uuid.
* <ol>
* <li>characters 0-31: md5 hex string of a start key. Since the length of the start key is not
* fixed, have to use the md5 instead which has a fix length.</li>
* <li>characters 32-39: a string of a date with format yyyymmdd. The date is the latest timestamp
* of cells in this file</li>
* <li>the remaining characters: the uuid.</li>
* </ol>
* Using md5 hex string of start key as the prefix of file name makes files with the same start
* key unique, they're different from the ones with other start keys
* The cells come from different regions might be in the same mob file by region split,
* this is allowed.
* Has the latest timestamp of cells in the file name in order to clean the expired mob files by
* TTL easily. If this timestamp is older than the TTL, it's regarded as expired.
*/
@InterfaceAudience.Private
public final class MobFileName {
private final String date;
private final String startKey;
private final String uuid;
private final String fileName;
private static final int STARTKEY_END_INDEX = 32;
private static final int DATE_END_INDEX = 40;
private static final int UUID_END_INDEX = 72;
/**
* @param startKey
* The start key.
* @param date
* The string of the latest timestamp of cells in this file, the format is yyyymmdd.
* @param uuid
* The uuid
*/
private MobFileName(byte[] startKey, String date, String uuid) {
this.startKey = MD5Hash.getMD5AsHex(startKey, 0, startKey.length);
this.uuid = uuid;
this.date = date;
this.fileName = this.startKey + this.date + this.uuid;
}
/**
* @param startKey
* The md5 hex string of the start key.
* @param date
* The string of the latest timestamp of cells in this file, the format is yyyymmdd.
* @param uuid
* The uuid
*/
private MobFileName(String startKey, String date, String uuid) {
this.startKey = startKey;
this.uuid = uuid;
this.date = date;
this.fileName = this.startKey + this.date + this.uuid;
}
/**
* Creates an instance of MobFileName
*
* @param startKey
* The md5 hex string of the start key.
* @param date
* The string of the latest timestamp of cells in this file, the format is yyyymmdd.
* @param uuid The uuid.
* @return An instance of a MobFileName.
*/
public static MobFileName create(byte[] startKey, String date, String uuid) {
return new MobFileName(startKey, date, uuid);
}
/**
* Creates an instance of MobFileName
*
* @param startKey
* The md5 hex string of the start key.
* @param date
* The string of the latest timestamp of cells in this file, the format is yyyymmdd.
* @param uuid The uuid.
* @return An instance of a MobFileName.
*/
public static MobFileName create(String startKey, String date, String uuid) {
return new MobFileName(startKey, date, uuid);
}
/**
* Creates an instance of MobFileName.
* @param fileName The string format of a file name.
* @return An instance of a MobFileName.
*/
public static MobFileName create(String fileName) {
// The format of a file name is md5HexString(0-31bytes) + date(32-39bytes) + UUID
// The date format is yyyyMMdd
String startKey = fileName.substring(0, STARTKEY_END_INDEX);
String date = fileName.substring(STARTKEY_END_INDEX, DATE_END_INDEX);
String uuid = fileName.substring(DATE_END_INDEX, UUID_END_INDEX);
return new MobFileName(startKey, date, uuid);
}
/**
* get startKey from MobFileName.
* @param fileName file name.
* @return startKey
*/
public static String getStartKeyFromName(final String fileName) {
return fileName.substring(0, STARTKEY_END_INDEX);
}
/**
* get date from MobFileName.
* @param fileName file name.
* @return date
*/
public static String getDateFromName(final String fileName) {
return fileName.substring(STARTKEY_END_INDEX, DATE_END_INDEX);
}
/**
* Gets the hex string of the md5 for a start key.
* @return The hex string of the md5 for a start key.
*/
public String getStartKey() {
return startKey;
}
/**
* Gets the date string. Its format is yyyymmdd.
* @return The date string.
*/
public String getDate() {
return this.date;
}
@Override
public int hashCode() {
return fileName.hashCode();
}
@Override
public boolean equals(Object anObject) {
if (this == anObject) {
return true;
}
if (anObject instanceof MobFileName) {
MobFileName another = (MobFileName) anObject;
return this.getFileName().equals(another.getFileName());
}
return false;
}
/**
* Gets the file name.
* @return The file name.
*/
public String getFileName() {
return this.fileName;
}
}