Class IntSum

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 Summary

Fields

Modifier and Type	Field	Description
private final Int128	sum	Sum of the values.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	IntSum()	Create an instance.
private	IntSum(Int128 sum)	Create an instance.

Method Summary

Modifier and Type	Method	Description
void	accept(int value)	Updates the state of the statistic to reflect the addition of value.
IntSum	combine(IntSum other)	Combines the state of the other statistic into this one.
static IntSum	create()	Creates an instance.
(package private) static IntSum	createFromRange(int[] values, int from, int to)	Create an instance using the specified range of values.
BigInteger	getAsBigInteger()	Gets the sum of all input values.
double	getAsDouble()	Gets the sum of all input values.
int	getAsInt()	Gets the sum of all input values.
long	getAsLong()	Gets the sum of all input values.
(package private) Int128	getSum()	Gets the sum.
static IntSum	of(int... values)	Returns an instance populated using the input values.
static IntSum	ofRange(int[] values, int from, int to)	Returns an instance populated using the specified range of values.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface IntConsumer

andThen

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.

ofRange

public static IntSum ofRange(int[] values,
 int from,
 int to)

Returns an instance populated using the specified range of values.

When the range is empty, the result is zero.

The getAsLong() result is valid for any range length; the getAsInt() result may overflow.

Parameters:

values - Values.

from - Inclusive start of the range.

to - Exclusive end of the range.

Returns:

IntSum instance.

Throws:

IndexOutOfBoundsException - if the sub-range is out of bounds

Since:

1.2

createFromRange

static IntSum createFromRange(int[] values,
 int from,
 int to)

Create an instance using the specified range of values.

Warning: No range checks are performed.

Parameters:

values - Values.

from - Inclusive start of the range.

to - Exclusive end of the range.

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:

• getAsBigInteger()

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:

• getAsBigInteger()

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()

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.