tl.lin.data.map

Class HMapIIW

java.lang.Object

tl.lin.data.map.HMapII

tl.lin.data.map.HMapIIW

All Implemented Interfaces:

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

public class HMapIIW
extends HMapII
implements org.apache.hadoop.io.Writable

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

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.MapII

DEFAULT_VALUE

Constructor Summary

Constructors

Constructor and Description
HMapIIW() Creates a HMapIIW object.

Method Summary

Methods

Modifier and Type	Method and Description
static HMapIIW	create(byte[] bytes) Creates a HMapIIW object from a byte array.
static HMapIIW	create(DataInput in) Creates a HMapIIW 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
int[]	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	lazyplus(HMapIIW m) In lazy decoding mode, 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.HMapII

clear, clone, containsKey, containsValue, dot, entrySet, get, getEntriesSortedByValue, getEntriesSortedByValue, increment, increment, isEmpty, keySet, 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.MapII

equals, hashCode

Constructor Detail

HMapIIW

public HMapIIW()

Creates a HMapIIW 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()
            throws IOException

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 HMapIIW create(DataInput in)
                      throws IOException

Creates a HMapIIW object from a DataInput.

Parameters:

in - source for reading the serialized representation

Returns:

a newly-created HMapIIW object

Throws:

IOException

create

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

Creates a HMapIIW object from a byte array.

Parameters:

bytes - raw serialized representation

Returns:

a newly-created HMapIIW 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 int[] 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

lazyplus

public void lazyplus(HMapIIW m)

In lazy decoding mode, adds values from keys of another map to this map. This map must have already been decoded, but the other map must not have been already decoded.

Parameters:

m - the other map

size

public int size()

Description copied from interface: MapII

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

Specified by:

size in interface MapII

Overrides:

size in class HMapII

Returns:

the number of key-value mappings in this map