org.apache.hadoop.hbase

Class RegionLocations

java.lang.Object

org.apache.hadoop.hbase.RegionLocations

@InterfaceAudience.Private
public class RegionLocations
extends Object

Container for holding a list of HRegionLocation's that correspond to the same range. The list is indexed by the replicaId. This is an immutable list, however mutation operations are provided which returns a new List via copy-on-write (assuming small number of locations)

Field Summary

Fields

Modifier and Type	Field and Description
private HRegionLocation[]	locations
private int	numNonNullElements

Constructor Summary

Constructors

Constructor and Description
RegionLocations(Collection<HRegionLocation> locations)
RegionLocations(HRegionLocation... locations) Constructs the region location list.

Method Summary

Modifier and Type	Method and Description
HRegionLocation	getDefaultRegionLocation()
HRegionLocation	getRegionLocation() Returns the first not-null region location in the list
HRegionLocation	getRegionLocation(int replicaId)
HRegionLocation	getRegionLocationByRegionName(byte[] regionName) Returns the region location from the list for matching regionName, which can be regionName or encodedRegionName
HRegionLocation[]	getRegionLocations()
boolean	isEmpty() Returns whether there are non-null elements in the list
private boolean	isGreaterThan(long a, long b, boolean checkForEquals)
RegionLocations	mergeLocations(RegionLocations other) Merges this RegionLocations list with the given list assuming same range, and keeping the most up to date version of the HRegionLocation entries from either list according to seqNum.
int	numNonNullElements() Returns the size of not-null locations
RegionLocations	remove(HRegionLocation location) Removes the given location from the list
RegionLocations	remove(int replicaId) Removes location of the given replicaId from the list
RegionLocations	removeByServer(ServerName serverName) Returns a new RegionLocations with the locations removed (set to null) which have the destination server as given.
RegionLocations	removeElementsWithNullLocation() Set the element to null if its getServerName method returns null.
private HRegionLocation	selectRegionLocation(HRegionLocation oldLocation, HRegionLocation location, boolean checkForEquals, boolean force)
int	size() Returns the size of the list even if some of the elements might be null.
String	toString()
RegionLocations	updateLocation(HRegionLocation location, boolean checkForEquals, boolean force) Updates the location with new only if the new location has a higher seqNum than the old one or force is true.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

numNonNullElements

private final int numNonNullElements

locations

private final HRegionLocation[] locations

Constructor Detail

RegionLocations

public RegionLocations(HRegionLocation... locations)

Constructs the region location list. The locations array should contain all the locations for known replicas for the region, and should be sorted in replicaId ascending order, although it can contain nulls indicating replicaIds that the locations of which are not known.

Parameters:

locations - an array of HRegionLocations for the same region range

RegionLocations

public RegionLocations(Collection<HRegionLocation> locations)

Method Detail

size

public int size()

Returns the size of the list even if some of the elements might be null.

Returns:

the size of the list (corresponding to the max replicaId)

numNonNullElements

public int numNonNullElements()

Returns the size of not-null locations

Returns:

the size of not-null locations

isEmpty

public boolean isEmpty()

Returns whether there are non-null elements in the list

Returns:

whether there are non-null elements in the list

removeByServer

public RegionLocations removeByServer(ServerName serverName)

Returns a new RegionLocations with the locations removed (set to null) which have the destination server as given.

Parameters:

serverName - the serverName to remove locations of

Returns:

an RegionLocations object with removed locations or the same object if nothing is removed

remove

public RegionLocations remove(HRegionLocation location)

Removes the given location from the list

Parameters:

location - the location to remove

Returns:

an RegionLocations object with removed locations or the same object if nothing is removed

remove

public RegionLocations remove(int replicaId)

Removes location of the given replicaId from the list

Parameters:

replicaId - the replicaId of the location to remove

Returns:

an RegionLocations object with removed locations or the same object if nothing is removed

removeElementsWithNullLocation

public RegionLocations removeElementsWithNullLocation()

Set the element to null if its getServerName method returns null. Returns null if all the elements are removed.

mergeLocations

public RegionLocations mergeLocations(RegionLocations other)

Merges this RegionLocations list with the given list assuming same range, and keeping the most up to date version of the HRegionLocation entries from either list according to seqNum. If seqNums are equal, the location from the argument (other) is taken.

Parameters:

other - the locations to merge with

Returns:

an RegionLocations object with merged locations or the same object if nothing is merged

selectRegionLocation

private HRegionLocation selectRegionLocation(HRegionLocation oldLocation,
                                             HRegionLocation location,
                                             boolean checkForEquals,
                                             boolean force)

updateLocation

public RegionLocations updateLocation(HRegionLocation location,
                                      boolean checkForEquals,
                                      boolean force)

Updates the location with new only if the new location has a higher seqNum than the old one or force is true.

Parameters:

location - the location to add or update

checkForEquals - whether to update the location if seqNums for the HRegionLocations for the old and new location are the same

force - whether to force update

Returns:

an RegionLocations object with updated locations or the same object if nothing is updated

isGreaterThan

private boolean isGreaterThan(long a,
                              long b,
                              boolean checkForEquals)

getRegionLocation

public HRegionLocation getRegionLocation(int replicaId)

getRegionLocationByRegionName

public HRegionLocation getRegionLocationByRegionName(byte[] regionName)

Returns the region location from the list for matching regionName, which can be regionName or encodedRegionName

Parameters:

regionName - regionName or encodedRegionName

Returns:

HRegionLocation found or null

getRegionLocations

public HRegionLocation[] getRegionLocations()

getDefaultRegionLocation

public HRegionLocation getDefaultRegionLocation()

getRegionLocation

public HRegionLocation getRegionLocation()

Returns the first not-null region location in the list

toString

public String toString()

Overrides:

toString in class Object