org.apache.hadoop.hbase
Class HColumnDescriptor

java.lang.Object
  org.apache.hadoop.hbase.HColumnDescriptor

All Implemented Interfaces:

java.lang.Comparable<HColumnDescriptor>, org.apache.hadoop.io.Writable, org.apache.hadoop.io.WritableComparable<HColumnDescriptor>

Direct Known Subclasses:

UnmodifyableHColumnDescriptor

public class HColumnDescriptor
extends java.lang.Object
implements org.apache.hadoop.io.WritableComparable<HColumnDescriptor>

An HColumnDescriptor contains information about a column family such as the number of versions, compression settings, etc. It is used as input when creating a table or adding a column. Once set, the parameters that specify a column cannot be changed without deleting the column and recreating it. If there is data stored in the column, it will be deleted when the column is deleted.

Field Summary

static java.lang.String	BLOCKCACHE
static java.lang.String	BLOCKSIZE Size of storefile/hfile 'blocks'.
static java.lang.String	BLOOMFILTER
static java.lang.String	CACHE_BLOOMS_ON_WRITE
static java.lang.String	CACHE_DATA_ON_WRITE
static java.lang.String	CACHE_INDEX_ON_WRITE
static java.lang.String	COMPRESSION
static java.lang.String	COMPRESSION_COMPACT
static java.lang.String	DATA_BLOCK_ENCODING
static boolean	DEFAULT_BLOCKCACHE Default setting for whether to use a block cache or not.
static int	DEFAULT_BLOCKSIZE Default size of blocks in files stored to the filesytem (hfiles).
static java.lang.String	DEFAULT_BLOOMFILTER Default setting for whether or not to use bloomfilters.
static boolean	DEFAULT_CACHE_BLOOMS_ON_WRITE Default setting for whether to cache bloom filter blocks on write if block caching is enabled.
static boolean	DEFAULT_CACHE_DATA_ON_WRITE Default setting for whether to cache data blocks on write if block caching is enabled.
static boolean	DEFAULT_CACHE_INDEX_ON_WRITE Default setting for whether to cache index blocks on write if block caching is enabled.
static java.lang.String	DEFAULT_COMPRESSION Default compression type.
static java.lang.String	DEFAULT_DATA_BLOCK_ENCODING Default data block encoding algorithm.
static boolean	DEFAULT_ENCODE_ON_DISK Default value of the flag that enables data block encoding on disk, as opposed to encoding in cache only.
static boolean	DEFAULT_EVICT_BLOCKS_ON_CLOSE Default setting for whether to evict cached blocks from the blockcache on close.
static boolean	DEFAULT_IN_MEMORY Default setting for whether to serve from memory or not.
static boolean	DEFAULT_KEEP_DELETED Default setting for preventing deleted from being collected immediately.
static int	DEFAULT_MIN_VERSIONS Default is not to keep a minimum of versions.
static int	DEFAULT_REPLICATION_SCOPE Default scope.
static int	DEFAULT_TTL Default time to live of cell contents.
static int	DEFAULT_VERSIONS Default number of versions of a record to keep.
static java.lang.String	ENCODE_ON_DISK
static java.lang.String	EVICT_BLOCKS_ON_CLOSE
static java.lang.String	FOREVER
static java.lang.String	KEEP_DELETED_CELLS
static java.lang.String	LENGTH
static java.lang.String	MIN_VERSIONS
static java.lang.String	REPLICATION_SCOPE
static java.lang.String	TTL
protected java.util.Map<ImmutableBytesWritable,ImmutableBytesWritable>	values

Constructor Summary

HColumnDescriptor()
Default constructor.

HColumnDescriptor(byte[] familyName)
Construct a column descriptor specifying only the family name The other attributes are defaulted.

HColumnDescriptor(byte[] familyName, int minVersions, int maxVersions, boolean keepDeletedCells, java.lang.String compression, boolean encodeOnDisk, java.lang.String dataBlockEncoding, boolean inMemory, boolean blockCacheEnabled, int blocksize, int timeToLive, java.lang.String bloomFilter, int scope)
Deprecated. use HColumnDescriptor(String) and setters

HColumnDescriptor(byte[] familyName, int maxVersions, java.lang.String compression, boolean inMemory, boolean blockCacheEnabled, int blocksize, int timeToLive, java.lang.String bloomFilter, int scope)
Deprecated. use HColumnDescriptor(String) and setters

HColumnDescriptor(byte[] familyName, int maxVersions, java.lang.String compression, boolean inMemory, boolean blockCacheEnabled, int timeToLive, java.lang.String bloomFilter)
Deprecated. use HColumnDescriptor(String) and setters

HColumnDescriptor(HColumnDescriptor desc)
Constructor.

HColumnDescriptor(java.lang.String familyName)
Construct a column descriptor specifying only the family name The other attributes are defaulted.

Method Summary

int	compareTo(HColumnDescriptor o)
boolean	equals(java.lang.Object obj)
int	getBlocksize()
StoreFile.BloomType	getBloomFilterType()
Compression.Algorithm	getCompactionCompression()
Compression.Algorithm	getCompactionCompressionType()
Compression.Algorithm	getCompression()
Compression.Algorithm	getCompressionType()
DataBlockEncoding	getDataBlockEncoding()
DataBlockEncoding	getDataBlockEncodingOnDisk()
boolean	getKeepDeletedCells()
int	getMaxVersions()
int	getMinVersions()
byte[]	getName()
java.lang.String	getNameAsString()
int	getScope()
int	getTimeToLive()
byte[]	getValue(byte[] key)
java.lang.String	getValue(java.lang.String key)
java.util.Map<ImmutableBytesWritable,ImmutableBytesWritable>	getValues()
int	hashCode()
boolean	isBlockCacheEnabled()
boolean	isInMemory()
static byte[]	isLegalFamilyName(byte[] b)
void	readFields(java.io.DataInput in)
void	remove(byte[] key)
HColumnDescriptor	setBlockCacheEnabled(boolean blockCacheEnabled)
HColumnDescriptor	setBlocksize(int s)
HColumnDescriptor	setBloomFilterType(StoreFile.BloomType bt)
HColumnDescriptor	setCacheBloomsOnWrite(boolean value)
HColumnDescriptor	setCacheDataOnWrite(boolean value)
HColumnDescriptor	setCacheIndexesOnWrite(boolean value)
HColumnDescriptor	setCompactionCompressionType(Compression.Algorithm type) Compression types supported in hbase.
HColumnDescriptor	setCompressionType(Compression.Algorithm type) Compression types supported in hbase.
HColumnDescriptor	setDataBlockEncoding(DataBlockEncoding type) Set data block encoding algorithm used in block cache.
HColumnDescriptor	setEncodeOnDisk(boolean encodeOnDisk) Set the flag indicating that we only want to encode data block in cache but not on disk.
HColumnDescriptor	setEvictBlocksOnClose(boolean value)
HColumnDescriptor	setInMemory(boolean inMemory)
HColumnDescriptor	setKeepDeletedCells(boolean keepDeletedCells)
HColumnDescriptor	setMaxVersions(int maxVersions)
HColumnDescriptor	setMinVersions(int minVersions)
HColumnDescriptor	setScope(int scope)
HColumnDescriptor	setTimeToLive(int timeToLive)
HColumnDescriptor	setValue(byte[] key, byte[] value)
HColumnDescriptor	setValue(java.lang.String key, java.lang.String value)
boolean	shouldCacheBloomsOnWrite()
boolean	shouldCacheDataOnWrite()
boolean	shouldCacheIndexesOnWrite()
boolean	shouldEvictBlocksOnClose()
java.lang.String	toString()
java.lang.String	toStringCustomizedValues()
void	write(java.io.DataOutput out)

Methods inherited from class java.lang.Object

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

Field Detail

COMPRESSION

public static final java.lang.String COMPRESSION

See Also:

Constant Field Values

COMPRESSION_COMPACT

public static final java.lang.String COMPRESSION_COMPACT

See Also:

Constant Field Values

ENCODE_ON_DISK

public static final java.lang.String ENCODE_ON_DISK

See Also:

Constant Field Values

DATA_BLOCK_ENCODING

public static final java.lang.String DATA_BLOCK_ENCODING

See Also:

Constant Field Values

BLOCKCACHE

public static final java.lang.String BLOCKCACHE

See Also:

Constant Field Values

CACHE_DATA_ON_WRITE

public static final java.lang.String CACHE_DATA_ON_WRITE

See Also:

Constant Field Values

CACHE_INDEX_ON_WRITE

public static final java.lang.String CACHE_INDEX_ON_WRITE

See Also:

Constant Field Values

CACHE_BLOOMS_ON_WRITE

public static final java.lang.String CACHE_BLOOMS_ON_WRITE

See Also:

Constant Field Values

EVICT_BLOCKS_ON_CLOSE

public static final java.lang.String EVICT_BLOCKS_ON_CLOSE

See Also:

Constant Field Values

BLOCKSIZE

public static final java.lang.String BLOCKSIZE

Size of storefile/hfile 'blocks'. Default is DEFAULT_BLOCKSIZE. Use smaller block sizes for faster random-access at expense of larger indices (more memory consumption).

See Also:

Constant Field Values

LENGTH

public static final java.lang.String LENGTH

See Also:

Constant Field Values

TTL

public static final java.lang.String TTL

See Also:

Constant Field Values

BLOOMFILTER

public static final java.lang.String BLOOMFILTER

See Also:

Constant Field Values

FOREVER

public static final java.lang.String FOREVER

See Also:

Constant Field Values

REPLICATION_SCOPE

public static final java.lang.String REPLICATION_SCOPE

See Also:

Constant Field Values

MIN_VERSIONS

public static final java.lang.String MIN_VERSIONS

See Also:

Constant Field Values

KEEP_DELETED_CELLS

public static final java.lang.String KEEP_DELETED_CELLS

See Also:

Constant Field Values

DEFAULT_COMPRESSION

public static final java.lang.String DEFAULT_COMPRESSION

Default compression type.

DEFAULT_ENCODE_ON_DISK

public static final boolean DEFAULT_ENCODE_ON_DISK

Default value of the flag that enables data block encoding on disk, as opposed to encoding in cache only. We encode blocks everywhere by default, as long as DATA_BLOCK_ENCODING is not NONE.

See Also:

Constant Field Values

DEFAULT_DATA_BLOCK_ENCODING

public static final java.lang.String DEFAULT_DATA_BLOCK_ENCODING

Default data block encoding algorithm.

DEFAULT_VERSIONS

public static final int DEFAULT_VERSIONS

Default number of versions of a record to keep.

See Also:

Constant Field Values

DEFAULT_MIN_VERSIONS

public static final int DEFAULT_MIN_VERSIONS

Default is not to keep a minimum of versions.

See Also:

Constant Field Values

DEFAULT_IN_MEMORY

public static final boolean DEFAULT_IN_MEMORY

Default setting for whether to serve from memory or not.

See Also:

Constant Field Values

DEFAULT_KEEP_DELETED

public static final boolean DEFAULT_KEEP_DELETED

Default setting for preventing deleted from being collected immediately.

See Also:

Constant Field Values

DEFAULT_BLOCKCACHE

public static final boolean DEFAULT_BLOCKCACHE

Default setting for whether to use a block cache or not.

See Also:

Constant Field Values

DEFAULT_CACHE_DATA_ON_WRITE

public static final boolean DEFAULT_CACHE_DATA_ON_WRITE

Default setting for whether to cache data blocks on write if block caching is enabled.

See Also:

Constant Field Values

DEFAULT_CACHE_INDEX_ON_WRITE

public static final boolean DEFAULT_CACHE_INDEX_ON_WRITE

Default setting for whether to cache index blocks on write if block caching is enabled.

See Also:

Constant Field Values

DEFAULT_BLOCKSIZE

public static final int DEFAULT_BLOCKSIZE

Default size of blocks in files stored to the filesytem (hfiles).

See Also:

Constant Field Values

DEFAULT_BLOOMFILTER

public static final java.lang.String DEFAULT_BLOOMFILTER

Default setting for whether or not to use bloomfilters.

DEFAULT_CACHE_BLOOMS_ON_WRITE

public static final boolean DEFAULT_CACHE_BLOOMS_ON_WRITE

Default setting for whether to cache bloom filter blocks on write if block caching is enabled.

See Also:

Constant Field Values

DEFAULT_TTL

public static final int DEFAULT_TTL

Default time to live of cell contents.

See Also:

Constant Field Values

DEFAULT_REPLICATION_SCOPE

public static final int DEFAULT_REPLICATION_SCOPE

Default scope.

See Also:

Constant Field Values

DEFAULT_EVICT_BLOCKS_ON_CLOSE

public static final boolean DEFAULT_EVICT_BLOCKS_ON_CLOSE

Default setting for whether to evict cached blocks from the blockcache on close.

See Also:

Constant Field Values

values

protected java.util.Map<ImmutableBytesWritable,ImmutableBytesWritable> values

Constructor Detail

HColumnDescriptor

public HColumnDescriptor()

Default constructor. Must be present for Writable.

HColumnDescriptor

public HColumnDescriptor(java.lang.String familyName)

Construct a column descriptor specifying only the family name The other attributes are defaulted.

Parameters:

familyName - Column family name. Must be 'printable' -- digit or letter -- and may not contain a :

HColumnDescriptor

public HColumnDescriptor(byte[] familyName)

Construct a column descriptor specifying only the family name The other attributes are defaulted.

Parameters:

familyName - Column family name. Must be 'printable' -- digit or letter -- and may not contain a :

HColumnDescriptor

public HColumnDescriptor(HColumnDescriptor desc)

Constructor. Makes a deep copy of the supplied descriptor. Can make a modifiable descriptor from an UnmodifyableHColumnDescriptor.

Parameters:

desc - The descriptor.

HColumnDescriptor

@Deprecated
public HColumnDescriptor(byte[] familyName,
                                    int maxVersions,
                                    java.lang.String compression,
                                    boolean inMemory,
                                    boolean blockCacheEnabled,
                                    int timeToLive,
                                    java.lang.String bloomFilter)

Deprecated. use HColumnDescriptor(String) and setters

Constructor

Parameters:

familyName - Column family name. Must be 'printable' -- digit or letter -- and may not contain a :

maxVersions - Maximum number of versions to keep

compression - Compression type

inMemory - If true, column data should be kept in an HRegionServer's cache

blockCacheEnabled - If true, MapFile blocks should be cached

timeToLive - Time-to-live of cell contents, in seconds (use HConstants.FOREVER for unlimited TTL)

bloomFilter - Bloom filter type for this column

Throws:

java.lang.IllegalArgumentException - if passed a family name that is made of other than 'word' characters: i.e. [a-zA-Z_0-9] or contains a :

java.lang.IllegalArgumentException - if the number of versions is <= 0

HColumnDescriptor

@Deprecated
public HColumnDescriptor(byte[] familyName,
                                    int maxVersions,
                                    java.lang.String compression,
                                    boolean inMemory,
                                    boolean blockCacheEnabled,
                                    int blocksize,
                                    int timeToLive,
                                    java.lang.String bloomFilter,
                                    int scope)

Deprecated. use HColumnDescriptor(String) and setters

Constructor

Parameters:

familyName - Column family name. Must be 'printable' -- digit or letter -- and may not contain a :

maxVersions - Maximum number of versions to keep

compression - Compression type

inMemory - If true, column data should be kept in an HRegionServer's cache

blockCacheEnabled - If true, MapFile blocks should be cached

blocksize - Block size to use when writing out storefiles. Use smaller block sizes for faster random-access at expense of larger indices (more memory consumption). Default is usually 64k.

timeToLive - Time-to-live of cell contents, in seconds (use HConstants.FOREVER for unlimited TTL)

bloomFilter - Bloom filter type for this column

scope - The scope tag for this column

Throws:

java.lang.IllegalArgumentException - if passed a family name that is made of other than 'word' characters: i.e. [a-zA-Z_0-9] or contains a :

java.lang.IllegalArgumentException - if the number of versions is <= 0

HColumnDescriptor

@Deprecated
public HColumnDescriptor(byte[] familyName,
                                    int minVersions,
                                    int maxVersions,
                                    boolean keepDeletedCells,
                                    java.lang.String compression,
                                    boolean encodeOnDisk,
                                    java.lang.String dataBlockEncoding,
                                    boolean inMemory,
                                    boolean blockCacheEnabled,
                                    int blocksize,
                                    int timeToLive,
                                    java.lang.String bloomFilter,
                                    int scope)

Deprecated. use HColumnDescriptor(String) and setters

Constructor

Parameters:

familyName - Column family name. Must be 'printable' -- digit or letter -- and may not contain a :

minVersions - Minimum number of versions to keep

maxVersions - Maximum number of versions to keep

keepDeletedCells - Whether to retain deleted cells until they expire up to maxVersions versions.

compression - Compression type

encodeOnDisk - whether to use the specified data block encoding on disk. If false, the encoding will be used in cache only.

dataBlockEncoding - data block encoding

inMemory - If true, column data should be kept in an HRegionServer's cache

blockCacheEnabled - If true, MapFile blocks should be cached

blocksize - Block size to use when writing out storefiles. Use smaller blocksizes for faster random-access at expense of larger indices (more memory consumption). Default is usually 64k.

timeToLive - Time-to-live of cell contents, in seconds (use HConstants.FOREVER for unlimited TTL)

bloomFilter - Bloom filter type for this column

scope - The scope tag for this column

Throws:

java.lang.IllegalArgumentException - if passed a family name that is made of other than 'word' characters: i.e. [a-zA-Z_0-9] or contains a :

java.lang.IllegalArgumentException - if the number of versions is <= 0

Method Detail

isLegalFamilyName

public static byte[] isLegalFamilyName(byte[] b)

Parameters:

b - Family name.

Returns:

b

Throws:

java.lang.IllegalArgumentException - If not null and not a legitimate family name: i.e. 'printable' and ends in a ':' (Null passes are allowed because b can be null when deserializing). Cannot start with a '.' either.

getName

public byte[] getName()

Returns:

Name of this column family

getNameAsString

public java.lang.String getNameAsString()

Returns:

Name of this column family

getValue

public byte[] getValue(byte[] key)

Parameters:

key - The key.

Returns:

The value.

getValue

public java.lang.String getValue(java.lang.String key)

Parameters:

key - The key.

Returns:

The value as a string.

getValues

public java.util.Map<ImmutableBytesWritable,ImmutableBytesWritable> getValues()

Returns:

All values.

setValue

public HColumnDescriptor setValue(byte[] key,
                                  byte[] value)

Parameters:

key - The key.

value - The value.

Returns:

this (for chained invocation)

remove

public void remove(byte[] key)

Parameters:

key - Key whose key and value we're to remove from HCD parameters.

setValue

public HColumnDescriptor setValue(java.lang.String key,
                                  java.lang.String value)

Parameters:

key - The key.

value - The value.

Returns:

this (for chained invocation)

getCompression

public Compression.Algorithm getCompression()

Returns:

compression type being used for the column family

getCompactionCompression

public Compression.Algorithm getCompactionCompression()

Returns:

compression type being used for the column family for major compression

getMaxVersions

public int getMaxVersions()

Returns:

maximum number of versions

setMaxVersions

public HColumnDescriptor setMaxVersions(int maxVersions)

Parameters:

maxVersions - maximum number of versions

Returns:

this (for chained invocation)

getBlocksize

public int getBlocksize()

Returns:

The storefile/hfile blocksize for this column family.

setBlocksize

public HColumnDescriptor setBlocksize(int s)

Parameters:

s - Blocksize to use when writing out storefiles/hfiles on this column family.

Returns:

this (for chained invocation)

getCompressionType

public Compression.Algorithm getCompressionType()

Returns:

Compression type setting.

setCompressionType

public HColumnDescriptor setCompressionType(Compression.Algorithm type)

Compression types supported in hbase. LZO is not bundled as part of the hbase distribution. See LZO Compression for how to enable it.

Parameters:

type - Compression type setting.

Returns:

this (for chained invocation)

getDataBlockEncodingOnDisk

public DataBlockEncoding getDataBlockEncodingOnDisk()

Returns:

data block encoding algorithm used on disk

setEncodeOnDisk

public HColumnDescriptor setEncodeOnDisk(boolean encodeOnDisk)

Set the flag indicating that we only want to encode data block in cache but not on disk.

Returns:

this (for chained invocation)

getDataBlockEncoding

public DataBlockEncoding getDataBlockEncoding()

Returns:

the data block encoding algorithm used in block cache and optionally on disk

setDataBlockEncoding

public HColumnDescriptor setDataBlockEncoding(DataBlockEncoding type)

Set data block encoding algorithm used in block cache.

Parameters:

type - What kind of data block encoding will be used.

Returns:

this (for chained invocation)

getCompactionCompressionType

public Compression.Algorithm getCompactionCompressionType()

Returns:

Compression type setting.

setCompactionCompressionType

public HColumnDescriptor setCompactionCompressionType(Compression.Algorithm type)

Compression types supported in hbase. LZO is not bundled as part of the hbase distribution. See LZO Compression for how to enable it.

Parameters:

type - Compression type setting.

Returns:

this (for chained invocation)

isInMemory

public boolean isInMemory()

Returns:

True if we are to keep all in use HRegionServer cache.

setInMemory

public HColumnDescriptor setInMemory(boolean inMemory)

Parameters:

inMemory - True if we are to keep all values in the HRegionServer cache

Returns:

this (for chained invocation)

getKeepDeletedCells

public boolean getKeepDeletedCells()

setKeepDeletedCells

public HColumnDescriptor setKeepDeletedCells(boolean keepDeletedCells)

Parameters:

keepDeletedCells - True if deleted rows should not be collected immediately.

Returns:

this (for chained invocation)

getTimeToLive

public int getTimeToLive()

Returns:

Time-to-live of cell contents, in seconds.

setTimeToLive

public HColumnDescriptor setTimeToLive(int timeToLive)

Parameters:

timeToLive - Time-to-live of cell contents, in seconds.

Returns:

this (for chained invocation)

getMinVersions

public int getMinVersions()

Returns:

The minimum number of versions to keep.

setMinVersions

public HColumnDescriptor setMinVersions(int minVersions)

Parameters:

minVersions - The minimum number of versions to keep. (used when timeToLive is set)

Returns:

this (for chained invocation)

isBlockCacheEnabled

public boolean isBlockCacheEnabled()

Returns:

True if MapFile blocks should be cached.

setBlockCacheEnabled

public HColumnDescriptor setBlockCacheEnabled(boolean blockCacheEnabled)

Parameters:

blockCacheEnabled - True if MapFile blocks should be cached.

Returns:

this (for chained invocation)

getBloomFilterType

public StoreFile.BloomType getBloomFilterType()

Returns:

bloom filter type used for new StoreFiles in ColumnFamily

setBloomFilterType

public HColumnDescriptor setBloomFilterType(StoreFile.BloomType bt)

Parameters:

bt - bloom filter type

Returns:

this (for chained invocation)

getScope

public int getScope()

Returns:

the scope tag

setScope

public HColumnDescriptor setScope(int scope)

Parameters:

scope - the scope tag

Returns:

this (for chained invocation)

shouldCacheDataOnWrite

public boolean shouldCacheDataOnWrite()

Returns:

true if we should cache data blocks on write

setCacheDataOnWrite

public HColumnDescriptor setCacheDataOnWrite(boolean value)

Parameters:

value - true if we should cache data blocks on write

Returns:

this (for chained invocation)

shouldCacheIndexesOnWrite

public boolean shouldCacheIndexesOnWrite()

Returns:

true if we should cache index blocks on write

setCacheIndexesOnWrite

public HColumnDescriptor setCacheIndexesOnWrite(boolean value)

Parameters:

value - true if we should cache index blocks on write

Returns:

this (for chained invocation)

shouldCacheBloomsOnWrite

public boolean shouldCacheBloomsOnWrite()

Returns:

true if we should cache bloomfilter blocks on write

setCacheBloomsOnWrite

public HColumnDescriptor setCacheBloomsOnWrite(boolean value)

Parameters:

value - true if we should cache bloomfilter blocks on write

Returns:

this (for chained invocation)

shouldEvictBlocksOnClose

public boolean shouldEvictBlocksOnClose()

Returns:

true if we should evict cached blocks from the blockcache on close

setEvictBlocksOnClose

public HColumnDescriptor setEvictBlocksOnClose(boolean value)

Parameters:

value - true if we should evict cached blocks from the blockcache on close

Returns:

this (for chained invocation)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

See Also:

Object.toString()

toStringCustomizedValues

public java.lang.String toStringCustomizedValues()

Returns:

Column family descriptor with only the customized attributes.

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

See Also:

Object.equals(java.lang.Object)

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

See Also:

Object.hashCode()

readFields

public void readFields(java.io.DataInput in)
                throws java.io.IOException

Specified by:

readFields in interface org.apache.hadoop.io.Writable

Throws:

java.io.IOException

write

public void write(java.io.DataOutput out)
           throws java.io.IOException

Specified by:

write in interface org.apache.hadoop.io.Writable

Throws:

java.io.IOException

compareTo

public int compareTo(HColumnDescriptor o)

Specified by:

compareTo in interface java.lang.Comparable<HColumnDescriptor>