java.lang.Object
org.apache.commons.statistics.descriptive.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
  • Field Details

    • sum

      private final Int128 sum
      Sum of the values.
  • Constructor Details

    • IntSum

      private IntSum()
      Create an instance.
    • IntSum

      private IntSum(Int128 sum)
      Create an instance.
      Parameters:
      sum - Sum of the values.
  • Method Details

    • 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.
    • getSum

      Int128 getSum()
      Gets the sum.

      This is package private for use in IntStatistics.

      Returns:
      the sum
    • 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.
    • getAsInt

      public int getAsInt()
      Gets the sum of all input values.

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

      Warning: This will raise an ArithmeticException if the result is not within the range [-2^31, 2^31).

      Specified by:
      getAsInt in interface IntSupplier
      Specified by:
      getAsInt in interface StatisticResult
      Returns:
      sum of all values.
      Throws:
      ArithmeticException - if the result overflows an int
      See Also:
    • getAsLong

      public long getAsLong()
      Gets the sum of all input values.

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

      Warning: This will raise an ArithmeticException if the result is not within the range [-2^63, 2^63).

      Specified by:
      getAsLong in interface LongSupplier
      Specified by:
      getAsLong in interface StatisticResult
      Returns:
      sum of all values.
      Throws:
      ArithmeticException - if the result overflows a long
      See Also:
    • 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

      public BigInteger getAsBigInteger()
      Gets the sum of all input values.

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

      Specified by:
      getAsBigInteger in interface StatisticResult
      Returns:
      sum of all values.
    • combine

      public IntSum combine(IntSum other)
      Description copied from interface: StatisticAccumulator
      Combines the state of the other statistic into this one.
      Specified by:
      combine in interface StatisticAccumulator<IntSum>
      Parameters:
      other - Another statistic to be combined.
      Returns:
      this instance after combining other.