Package org.apache.hadoop.util.hash

Class MurmurHash

java.lang.Object

org.apache.hadoop.util.hash.Hash

org.apache.hadoop.util.hash.MurmurHash

@Private
@Unstable
public class MurmurHash
extends Hash

This is a very fast, non-cryptographic hash suitable for general hash-based lookup. See http://murmurhash.googlepages.com/ for more details.

The C version of MurmurHash 2.0 found at that site was ported to Java by Andrzej Bialecki (ab at getopt org).

Field Summary

Fields inherited from class org.apache.hadoop.util.hash.Hash

INVALID_HASH, JENKINS_HASH, MURMUR_HASH

Constructor Summary

Constructors

Constructor	Description
MurmurHash()

Method Summary

Modifier and Type	Method	Description
static Hash	getInstance()
int	hash(byte[] data, int length, int seed)	Calculate a hash using bytes from 0 to length, and the provided seed value
int	hash(byte[] data, int offset, int length, int seed)

Methods inherited from class org.apache.hadoop.util.hash.Hash

getHashType, getInstance, getInstance, hash, hash, parseHashType

Methods inherited from class java.lang.Object

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

Constructor Details

MurmurHash

public MurmurHash()

Method Details

getInstance

public static Hash getInstance()

hash

public int hash(byte[] data,
 int length,
 int seed)

Description copied from class: Hash

Calculate a hash using bytes from 0 to length, and the provided seed value

Specified by:

hash in class Hash

Parameters:

data - input bytes

length - length of the valid bytes to consider

seed - seed value

Returns:

hash value

hash

public int hash(byte[] data,
 int offset,
 int length,
 int seed)