Package org.apache.datasketches.tuple

Class Util

  • public final class Util
extends Object
    Common utility functions for Tuples

    • Constructor Detail

      • Util

        public Util()

    • Method Detail

      • 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