tl.lin.data.map

Class HMapIDW

java.lang.Object

tl.lin.data.map.HMapID

tl.lin.data.map.HMapIDW

All Implemented Interfaces:

Serializable, Cloneable, org.apache.hadoop.io.Writable, MapID

public class HMapIDW
extends HMapID
implements org.apache.hadoop.io.Writable

Writable representing a map where keys are ints and values are doubles.

One notable feature of this class is the ability to support lazy decoding, controlled by the setLazyDecodeFlag(boolean) method. In lazy decoding mode, when an object of this type is deserialized, key-value pairs are not inserted into the map, but rather held in arrays. The reduces memory used in cases where random access to values is not required. In lazy decoding mode, the raw keys and values may be fetched by the getKeys() and getValues() methods, respectively. The map can be subsequently populated with the decode() method.

See Also:

Serialized Form

Field Summary

Fields inherited from interface tl.lin.data.map.MapID

DEFAULT_VALUE

Constructor Summary

Constructors

Constructor and Description
HMapIDW() Creates a HMapIDW object.

Method Summary

Methods

Modifier and Type	Method and Description
static HMapIDW	create(byte[] bytes) Creates a HMapIDW object from a byte array.
static HMapIDW	create(DataInput in) Creates a HMapIDW object from a DataInput.
void	decode() In lazy decoding mode, populates the map with deserialized data.
int[]	getKeys() In lazy decoding mode, returns an array of all the keys if the map hasn't been decoded yet.
static boolean	getLazyDecodeFlag() Returns the value of the lazy decoding flag
double[]	getValues() In lazy decoding mode, returns an array of all the values if the map hasn't been decoded yet.
boolean	isDecoded() Returns whether or not this map has been decoded.
void	plus(HMapIDW m) Adds values from keys of another map to this map.
void	readFields(DataInput in) Deserializes the map.
byte[]	serialize() Returns the serialized representation of this object as a byte array.
static void	setLazyDecodeFlag(boolean b) Sets the lazy decoding flag.
int	size() Returns the number of key-value mappings in this map.
void	write(DataOutput out) Serializes the map.

Methods inherited from class tl.lin.data.map.HMapID

clear, clone, containsKey, containsValue, dot, entrySet, get, getEntriesSortedByValue, getEntriesSortedByValue, increment, increment, isEmpty, keySet, length, normalize, plus, put, putAll, remove, toString, values

Methods inherited from class java.lang.Object

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

Methods inherited from interface tl.lin.data.map.MapID

equals, hashCode

Constructor Detail

HMapIDW

public HMapIDW()

Creates a HMapIDW object.

Method Detail

readFields

public void readFields(DataInput in)
                throws IOException

Deserializes the map.

Specified by:

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

Parameters:

in - source for raw byte representation

Throws:

IOException

decode

public void decode()

In lazy decoding mode, populates the map with deserialized data. Otherwise, does nothing.

Throws:

IOException

isDecoded

public boolean isDecoded()

Returns whether or not this map has been decoded. If not in lazy decoding mode, this method always return true.

write

public void write(DataOutput out)
           throws IOException

Serializes the map.

Specified by:

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

Parameters:

out - where to write the raw byte representation

Throws:

IOException

serialize

public byte[] serialize()
                 throws IOException

Returns the serialized representation of this object as a byte array.

Returns:

byte array representing the serialized representation of this object

Throws:

IOException

create

public static HMapIDW create(DataInput in)
                      throws IOException

Creates a HMapIDW object from a DataInput.

Parameters:

in - source for reading the serialized representation

Returns:

a newly-created HMapIDW object

Throws:

IOException

create

public static HMapIDW create(byte[] bytes)
                      throws IOException

Creates a HMapIDW object from a byte array.

Parameters:

bytes - raw serialized representation

Returns:

a newly-created HMapIDW object

Throws:

IOException

setLazyDecodeFlag

public static void setLazyDecodeFlag(boolean b)

Sets the lazy decoding flag.

getLazyDecodeFlag

public static boolean getLazyDecodeFlag()

Returns the value of the lazy decoding flag

getKeys

public int[] getKeys()

In lazy decoding mode, returns an array of all the keys if the map hasn't been decoded yet. Otherwise, returns null.

Returns:

an array of all the keys

getValues

public double[] getValues()

In lazy decoding mode, returns an array of all the values if the map hasn't been decoded yet. Otherwise, returns null.

Returns:

an array of all the values

plus

public void plus(HMapIDW m)

Adds values from keys of another map to this map. This map will be decoded if it hasn't already been decode. The other map need not be decoded.

Parameters:

m - the other map

size

public int size()

Description copied from interface: MapID

Returns the number of key-value mappings in this map.

Specified by:

size in interface MapID

Overrides:

size in class HMapID

Returns:

the number of key-value mappings in this map