com.jn.langx.util.hash

类 Hashs

java.lang.Object

com.jn.langx.util.hash.Hashs

public class Hashs
extends Object

从以下版本开始:

4.4.0

构造器概要

构造器

构造器和说明
Hashs()

方法概要

限定符和类型	方法和说明
static <H extends Hasher> H	getHasher(String hasherName, Object initParams) Get a singleton instance of hash function of a given type.
static long	hash(Hasher hasher, byte[] bytes) Calculate a hash using all bytes from the input argument, and a seed of 0.
static long	hash(Hasher hasher, byte[] bytes, int length, long seed) 一次性计算 hash Calculate a hash using bytes from 0 to length, and the provided seed value
static long	hash(Hasher hasher, byte[] bytes, long seed) 一次性计算 hash Calculate a hash using all bytes from the input argument, and a provided seed value.
static long	hash(String hasher, Object initParams, byte[] bytes, int length, long seed)
static int	hashToIndex(int hash, int length) A function that calculates the index (e.g. to be used in an array/list) for a given hash.

从类继承的方法 java.lang.Object

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

构造器详细资料

Hashs

public Hashs()

方法详细资料

hash

public static long hash(Hasher hasher,
                        byte[] bytes)

Calculate a hash using all bytes from the input argument, and a seed of 0.

参数:

bytes - input bytes

返回:

hash value

hash

public static long hash(Hasher hasher,
                        byte[] bytes,
                        long seed)

一次性计算 hash

Calculate a hash using all bytes from the input argument, and a provided seed value.

参数:

bytes - input bytes

seed - seed value

返回:

hash value

hash

public static long hash(Hasher hasher,
                        byte[] bytes,
                        int length,
                        long seed)

一次性计算 hash

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

参数:

bytes - input bytes

length - length of the valid bytes to consider

seed - seed value

返回:

hash value

hash

public static long hash(String hasher,
                        Object initParams,
                        byte[] bytes,
                        int length,
                        long seed)

getHasher

public static <H extends Hasher> H getHasher(String hasherName,
                                             Object initParams)

Get a singleton instance of hash function of a given type.

参数:

hasherName - predefined hash type

返回:

hash function instance, or null if type is invalid

hashToIndex

public static int hashToIndex(int hash,
                              int length)

A function that calculates the index (e.g. to be used in an array/list) for a given hash. The returned value will always be equal or larger than 0 and will always be smaller than 'length'. The reason this function exists is to deal correctly with negative and especially the Integer.MIN_VALUE; since that can't be used safely with a Math.abs function.

参数:

length - the length of the array/list

返回:

the mod of the hash

抛出:

IllegalArgumentException - if length is smaller than 1.

从以下版本开始:

4.4.1