org.apache.activemq.apollo.util

Interface Hasher<N,K>

Type Parameters:

N -

K -

All Known Implementing Classes:

Hasher.BinaryHasher, Hasher.Native, Hasher.ToStringHasher

public interface Hasher<N,K>

Implementing this interface allows an object to customize how hash values are computed for Node objects and Key objects.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Hasher.BinaryHasher<N,K> A Hasher implemenation which first convert the Node and Key to byte arrays before calculating the hash using a HashAlgorithim.
static interface	Hasher.HashAlgorithim Used to calculate the hash of a binary buffer.
static class	Hasher.MessageDigestFactory A HashAlgorithim instance which use a MessageDigest algorithim to compute the hash value.
static class	Hasher.Native This Hasher implementation works with any type of object by using the Object.hashCode() method of the Node and Keys objects to compute the hash.
static class	Hasher.ToStringCodec Used to convert an object to a byte[] by basically doing: Object.toString().getBytes("UTF-8")
static class	Hasher.ToStringHasher This Hasher implementation works with any type of object by using Object.toString() and uses a checksum to compute the hash of the key and value.

Field Summary

Fields

Modifier and Type	Field and Description
static Hasher.HashAlgorithim	CRC32 A HashAlgorithim instance which uses CRC32 checksum algorithim to compute the hash value.
static Hasher.HashAlgorithim	FNV1A A HashAlgorithim instance which uses the Fowler/Noll/Vo FNV-1a hash algorithim to compute the hash value.
static long	INTEGER_MASK
static Hasher.HashAlgorithim	JENKINS A HashAlgorithim instance which uses the Jenkins hash algorithim to compute the hash value.
static Hasher.HashAlgorithim	MD5
static Hasher.HashAlgorithim	MURMUR A HashAlgorithim instance which uses the Murmur hash algorithim to compute the hash value.

Method Summary

Methods

Modifier and Type	Method and Description
int	hashKey(K value)
int	hashNode(N node, int i)

Field Detail

MD5

static final Hasher.HashAlgorithim MD5

INTEGER_MASK

static final long INTEGER_MASK

See Also:

Constant Field Values

FNV1A

static final Hasher.HashAlgorithim FNV1A

A HashAlgorithim instance which uses the Fowler/Noll/Vo FNV-1a hash algorithim to compute the hash value.

see: http://en.wikipedia.org/wiki/Fowler-Noll-Vo_hash_function

MURMUR

static final Hasher.HashAlgorithim MURMUR

A HashAlgorithim instance which uses the Murmur hash algorithim to compute the hash value.

lifted from: https://svn.apache.org/repos/asf/hadoop/hbase/trunk/src/java/org/apache/hadoop/hbase/util/MurmurHash.java

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).

JENKINS

static final Hasher.HashAlgorithim JENKINS

A HashAlgorithim instance which uses the Jenkins hash algorithim to compute the hash value.

lifted from: https://svn.apache.org/repos/asf/hadoop/hbase/trunk/src/java/org/apache/hadoop/hbase/util/MurmurHash.java

lookup3.c, by Bob Jenkins, May 2006, Public Domain.

 You can use this free for any purpose.  It's in the public domain.
 It has no warranty.
 

See Also:

lookup3.c, Hash Functions (and how this function compares to others such as CRC, MD?, etc, Has update on the Dr. Dobbs Article

CRC32

static final Hasher.HashAlgorithim CRC32

A HashAlgorithim instance which uses CRC32 checksum algorithim to compute the hash value.

Method Detail

hashNode

int hashNode(N node,
           int i)

hashKey

int hashKey(K value)