Package org.apache.commons.statistics.descriptive

Class LongSum

  • All Implemented Interfaces:
    DoubleSupplier, IntSupplier, LongConsumer, LongSupplier, LongStatistic, StatisticAccumulator<LongSum>, StatisticResult
    public final class LongSum
extends Object
implements LongStatistic, StatisticAccumulator<LongSum>
    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.

    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 LongSum create()
        Creates an instance.

        The initial result is zero.

        Returns:
        LongSum instance.

      • of

        public static LongSum of​(long... values)
        Returns an instance populated using the input values.

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

        Parameters:
        values - Values.
        Returns:
        LongSum instance.

      • accept

        public void accept​(long value)
        Updates the state of the statistic to reflect the addition of value.
        Specified by:
        accept in interface LongConsumer
        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()