Package org.apache.datasketches.tuple

Class Util

java.lang.Object
org.apache.datasketches.tuple.Util
public final class Util extends Object
Common utility functions for Tuples

  • Constructor Details

    • Util

      public Util()

  • Method Details

    • doubleToLongArray

      public static final long[] doubleToLongArray(double value)
      Converts a double to a long[].
      Parameters:
      value - the given double value
      Returns:
      the long array

    • stringToByteArray

      public static final byte[] stringToByteArray(String value)
      Converts a String to a UTF_8 byte array. If the given value is either null or empty this method returns null.
      Parameters:
      value - the given String value
      Returns:
      the UTF_8 byte array

    • computeSeedHash

      public static short computeSeedHash(long seed)
      Computes and checks the 16-bit seed hash from the given long seed. The seed hash may not be zero in order to maintain compatibility with older serialized versions that did not have this concept.
      Parameters:
      seed - See Update Hash Seed
      Returns:
      the seed hash.

    • checkSeedHashes

      public static final void checkSeedHashes(short seedHashA, short seedHashB)
      Checks the two given seed hashes. If they are not equal, this method throws an Exception.
      Parameters:
      seedHashA - given seed hash A
      seedHashB - given seed hash B

    • getStartingCapacity

      public static int getStartingCapacity(int nomEntries, int lgResizeFactor)
      Gets the starting capacity of a new sketch given the Nominal Entries and the log Resize Factor.
      Parameters:
      nomEntries - the given Nominal Entries
      lgResizeFactor - the given log Resize Factor
      Returns:
      the starting capacity

    • stringConcat

      public static String stringConcat(String[] strArr)
      Concatenate array of Strings to a single String.
      Parameters:
      strArr - the given String array
      Returns:
      the concatenated String

    • stringHash

      public static long stringHash(String s)
      Parameters:
      s - the string to hash
      Returns:
      the hash of the string

    • stringArrHash

      public static long stringArrHash(String[] strArray)
      Parameters:
      strArray - array of Strings
      Returns:
      long hash of concatenated strings.

    • copySummaryArray

      public static <S extends Summary> S[] copySummaryArray(S[] summaryArr)
      Will copy compact summary arrays as well as hashed summary tables (with nulls).
      Type Parameters:
      S - type of summary
      Parameters:
      summaryArr - the given summary array or table
      Returns:
      the copy

    • newSummaryArray

      public static <S extends Summary> S[] newSummaryArray(S[] summaryArr, int length)
      Creates a new Summary Array with the specified length
      Type Parameters:
      S - the summary class type
      Parameters:
      summaryArr - example array, only used to obtain the component type. It has no data.
      length - the desired length of the returned array.
      Returns:
      a new Summary Array with the specified length