org.apache.hadoop.hbase.mob

Class MobFileName

java.lang.Object

org.apache.hadoop.hbase.mob.MobFileName

@InterfaceAudience.Private
public final class MobFileName
extends Object

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.

1. 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.
2. characters 32-39: a string of a date with format yyyymmdd. The date is the latest timestamp of cells in this file
3. the remaining characters: the uuid.

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.

Method Summary

Modifier and Type	Method and Description
static MobFileName	create(byte[] startKey, String date, String uuid) Creates an instance of MobFileName
static MobFileName	create(String fileName) Creates an instance of MobFileName.
static MobFileName	create(String startKey, String date, String uuid) Creates an instance of MobFileName
boolean	equals(Object anObject)
String	getDate() Gets the date string.
static String	getDateFromName(String fileName) get date from MobFileName.
String	getFileName() Gets the file name.
String	getStartKey() Gets the hex string of the md5 for a start key.
static String	getStartKeyFromName(String fileName) get startKey from MobFileName.
int	hashCode()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Method Detail

create

public static MobFileName create(byte[] startKey,
                                 String date,
                                 String uuid)

Creates an instance of MobFileName

Parameters:

startKey - The md5 hex string of the start key.

date - The string of the latest timestamp of cells in this file, the format is yyyymmdd.

uuid - The uuid.

Returns:

An instance of a MobFileName.

create

public static MobFileName create(String startKey,
                                 String date,
                                 String uuid)

Creates an instance of MobFileName

Parameters:

startKey - The md5 hex string of the start key.

date - The string of the latest timestamp of cells in this file, the format is yyyymmdd.

uuid - The uuid.

Returns:

An instance of a MobFileName.

create

public static MobFileName create(String fileName)

Creates an instance of MobFileName.

Parameters:

fileName - The string format of a file name.

Returns:

An instance of a MobFileName.

getStartKeyFromName

public static String getStartKeyFromName(String fileName)

get startKey from MobFileName.

Parameters:

fileName - file name.

Returns:

startKey

getDateFromName

public static String getDateFromName(String fileName)

get date from MobFileName.

Parameters:

fileName - file name.

Returns:

date

getStartKey

public String getStartKey()

Gets the hex string of the md5 for a start key.

Returns:

The hex string of the md5 for a start key.

getDate

public String getDate()

Gets the date string. Its format is yyyymmdd.

Returns:

The date string.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object anObject)

Overrides:

equals in class Object

getFileName

public String getFileName()

Gets the file name.

Returns:

The file name.