HashFunction (Apache Hadoop Common 3.5.0 API)
Description: declaration: package: org.apache.hadoop.util.bloom, class: HashFunction

Package org.apache.hadoop.util.bloom

# Class HashFunction

java.lang.Object
org.apache.hadoop.util.bloom.HashFunction

@Public @Stable public final class HashFunction extends Object
Implements a hash object that returns a certain number of hashed values.

See Also:
  - `The general behavior of a key being stored in a filter`
  - `The general behavior of a filter`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `HashFunction(int maxValue, int nbHash, int hashType)`
  Constructor.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `clear()`
  Clears this hash function.
  `int[]`
  `hash(Key k)`
  Hashes a specified key into several integers.

  ### Methods inherited from class java.lang.Object

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

- ## Constructor Details

  - ### HashFunction

    public HashFunction(int maxValue, int nbHash, int hashType)
    Constructor.

    Builds a hash function that must obey to a given maximum number of returned values and a highest value.

    Parameters:
      `maxValue` - The maximum highest returned value.
      `nbHash` - The number of resulting hashed values.
      `hashType` - type of the hashing function (see `Hash`).

- ## Method Details

  - ### clear

    public void clear()
    Clears this hash function. A NOOP

  - ### hash

    public int[] hash(Key k)
    Hashes a specified key into several integers.
    Parameters:
      `k` - The specified key.
    Returns:
      The array of hashed values.