Package org.apache.commons.statistics.descriptive

Class IntSum

  • All Implemented Interfaces:
    DoubleSupplier, IntConsumer, IntSupplier, LongSupplier, IntStatistic, StatisticAccumulator<IntSum>, StatisticResult
    public final class IntSum
extends Object
implements IntStatistic, StatisticAccumulator<IntSum>
    Returns the sum of the available values.
    • The result is zero if no values are added.

    This class uses an exact integer sum. The exact sum is returned using getAsBigInteger(). Methods that return int or long primitives will raise an exception if the result overflows. The long value is safe up to the maximum array length for any input int[] data. The long value can overflow when instances are combined.

    Note that the implementation does not use BigInteger arithmetic; for performance the sum is computed using primitives to create a signed 128-bit integer. Support is provided for at least 263 observations.

    This class is designed to work with (though does not require) streams.

    This implementation is not thread safe. If multiple threads access an instance of this class concurrently, and at least one of the threads invokes the accept or combine method, it must be synchronized externally.

    However, it is safe to use accept and combine as accumulator and combiner functions of Collector on a parallel stream, because the parallel implementation of Stream.collect() provides the necessary partitioning, isolation, and merging of results for safe and efficient parallel execution.

    Since:
    1.1

    • Method Detail

      • create

        public static IntSum create()
        Creates an instance.

        The initial result is zero.

        Returns:
        IntSum instance.

      • of

        public static IntSum of​(int... values)
        Returns an instance populated using the input values.

        When the input is an empty array, the result is zero.

        The getAsLong() result is valid for any input int[] length; the getAsInt() result may overflow.

        Parameters:
        values - Values.
        Returns:
        IntSum instance.

      • accept

        public void accept​(int value)
        Updates the state of the statistic to reflect the addition of value.
        Specified by:
        accept in interface IntConsumer
        Parameters:
        value - Value.

      • getAsDouble

        public double getAsDouble()
        Gets the sum of all input values.

        When no values have been added, the result is zero.

        Note that this conversion can lose information about the precision of the BigInteger value.

        Specified by:
        getAsDouble in interface DoubleSupplier
        Returns:
        sum of all values.
        See Also:
        getAsBigInteger()