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.

Nested Class Summary

static class

HColumnDescriptor.CompressionType Deprecated. Compression now means which compression library rather than 'what' to compress.

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	COMPRESSION
static java.lang.String	COMPRESSION_COMPACT
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 java.lang.String	DEFAULT_COMPRESSION Default compression type.
static boolean	DEFAULT_IN_MEMORY Default setting for whether to serve from memory or not.
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	FOREVER
static java.lang.String	LENGTH
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 maxVersions, java.lang.String compression, boolean inMemory, boolean blockCacheEnabled, int blocksize, int timeToLive, java.lang.String bloomFilter, int scope)
Constructor

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

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()
int	getMaxVersions()
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)
void	setBlockCacheEnabled(boolean blockCacheEnabled)
void	setBlocksize(int s)
void	setBloomFilterType(StoreFile.BloomType bt)
void	setCompactionCompressionType(Compression.Algorithm type) Compression types supported in hbase.
void	setCompressionType(Compression.Algorithm type) Compression types supported in hbase.
void	setInMemory(boolean inMemory)
void	setMaxVersions(int maxVersions)
void	setScope(int scope)
void	setTimeToLive(int timeToLive)
void	setValue(byte[] key, byte[] value)
void	setValue(java.lang.String key, java.lang.String value)
java.lang.String	toString()
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

BLOCKCACHE

public static final java.lang.String BLOCKCACHE

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

DEFAULT_COMPRESSION

public static final java.lang.String DEFAULT_COMPRESSION

Default compression type.

DEFAULT_VERSIONS

public static final int DEFAULT_VERSIONS

Default number of versions of a record to keep.

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_BLOCKCACHE

public static final boolean DEFAULT_BLOCKCACHE

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

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_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

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

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

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

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

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 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 void setValue(byte[] key,
                     byte[] value)

Parameters:

key - The key.

value - The value.

remove

public void remove(byte[] key)

Parameters:

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

setValue

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

Parameters:

key - The key.

value - The value.

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 void setMaxVersions(int maxVersions)

Parameters:

maxVersions - maximum number of versions

getBlocksize

public int getBlocksize()

Returns:

The storefile/hfile blocksize for this column family.

setBlocksize

public void setBlocksize(int s)

Parameters:

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

getCompressionType

public Compression.Algorithm getCompressionType()

Returns:

Compression type setting.

setCompressionType

public void 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.

getCompactionCompressionType

public Compression.Algorithm getCompactionCompressionType()

Returns:

Compression type setting.

setCompactionCompressionType

public void 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.

isInMemory

public boolean isInMemory()

Returns:

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

setInMemory

public void setInMemory(boolean inMemory)

Parameters:

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

getTimeToLive

public int getTimeToLive()

Returns:

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

setTimeToLive

public void setTimeToLive(int timeToLive)

Parameters:

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

isBlockCacheEnabled

public boolean isBlockCacheEnabled()

Returns:

True if MapFile blocks should be cached.

setBlockCacheEnabled

public void setBlockCacheEnabled(boolean blockCacheEnabled)

Parameters:

blockCacheEnabled - True if MapFile blocks should be cached.

getBloomFilterType

public StoreFile.BloomType getBloomFilterType()

Returns:

bloom filter type used for new StoreFiles in ColumnFamily

setBloomFilterType

public void setBloomFilterType(StoreFile.BloomType bt)

Parameters:

bt - bloom filter type

getScope

public int getScope()

Returns:

the scope tag

setScope

public void setScope(int scope)

Parameters:

scope - the scope tag

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

See Also:

Object.toString()

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>