net.spy.memcached
Enum HashAlgorithm

java.lang.Object
  java.lang.Enum<HashAlgorithm>
      net.spy.memcached.HashAlgorithm

All Implemented Interfaces:

Serializable, Comparable<HashAlgorithm>

public enum HashAlgorithm
extends Enum<HashAlgorithm>

Known hashing algorithms for locating a server for a key. Note that all hash algorithms return 64-bits of hash, but only the lower 32-bits are significant. This allows a positive 32-bit number to be returned for all cases.

Enum Constant Summary

CRC32_HASH
CRC32_HASH as used by the perl API.

FNV1_32_HASH
32-bit FNV1.

FNV1_64_HASH
FNV hashes are designed to be fast while maintaining a low collision rate.

FNV1A_32_HASH
32-bit FNV1a.

FNV1A_64_HASH
Variation of FNV.

KETAMA_HASH
MD5-based hash algorithm used by ketama.

NATIVE_HASH
Native hash (String.hashCode()).

Method Summary

static byte[]	computeMd5(String k) Get the md5 of the given key.
long	hash(String k) Compute the hash for the given key.
static HashAlgorithm	valueOf(String name) Returns the enum constant of this type with the specified name.
static HashAlgorithm[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

NATIVE_HASH

public static final HashAlgorithm NATIVE_HASH

Native hash (String.hashCode()).

CRC32_HASH

public static final HashAlgorithm CRC32_HASH

CRC32_HASH as used by the perl API. This will be more consistent both across multiple API users as well as java versions, but is mostly likely significantly slower.

FNV1_64_HASH

public static final HashAlgorithm FNV1_64_HASH

FNV hashes are designed to be fast while maintaining a low collision rate. The FNV speed allows one to quickly hash lots of data while maintaining a reasonable collision rate.

See Also:

fnv comparisons, fnv at wikipedia

FNV1A_64_HASH

public static final HashAlgorithm FNV1A_64_HASH

Variation of FNV.

FNV1_32_HASH

public static final HashAlgorithm FNV1_32_HASH

32-bit FNV1.

FNV1A_32_HASH

public static final HashAlgorithm FNV1A_32_HASH

32-bit FNV1a.

KETAMA_HASH

public static final HashAlgorithm KETAMA_HASH

MD5-based hash algorithm used by ketama.

Method Detail

values

public static HashAlgorithm[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (HashAlgorithm c : HashAlgorithm.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static HashAlgorithm valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

hash

public long hash(String k)

Compute the hash for the given key.

Returns:

a positive integer hash

computeMd5

public static byte[] computeMd5(String k)

Get the md5 of the given key.