java.lang.Object
java.util.IntSummaryStatistics
 All Implemented Interfaces:
IntConsumer
public class IntSummaryStatistics extends Object implements IntConsumer
A state object for collecting statistics such as count, min, max, sum, and
average.
This class is designed to work with (though does not require) streams. For example, you can compute summary statistics on a stream of ints with:
IntSummaryStatistics stats = intStream.collect(IntSummaryStatistics::new,
IntSummaryStatistics::accept,
IntSummaryStatistics::combine);
IntSummaryStatistics
can be used as a
reduction
target for a stream. For example:
IntSummaryStatistics stats = people.stream()
.collect(Collectors.summarizingInt(Person::getDependents));
This computes, in a single pass, the count of people, as well as the minimum,
maximum, sum, and average of their number of dependents. Implementation Note:
 This implementation is not thread safe. However, it is safe to use
Collectors.summarizingInt()
on a parallel stream, because the parallel implementation ofStream.collect()
provides the necessary partitioning, isolation, and merging of results for safe and efficient parallel execution.This implementation does not check for overflow of the sum.
 Since:
 1.8

Constructor Summary
Constructors Constructor Description IntSummaryStatistics()
Constructs an empty instance with zero count, zero sum,Integer.MAX_VALUE
min,Integer.MIN_VALUE
max and zero average.IntSummaryStatistics(long count, int min, int max, long sum)
Constructs a nonempty instance with the specifiedcount
,min
,max
, andsum
. 
Method Summary
Modifier and Type Method Description void
accept(int value)
Records a new value into the summary informationvoid
combine(IntSummaryStatistics other)
Combines the state of anotherIntSummaryStatistics
into this one.double
getAverage()
Returns the arithmetic mean of values recorded, or zero if no values have been recorded.long
getCount()
Returns the count of values recorded.int
getMax()
Returns the maximum value recorded, orInteger.MIN_VALUE
if no values have been recorded.int
getMin()
Returns the minimum value recorded, orInteger.MAX_VALUE
if no values have been recorded.long
getSum()
Returns the sum of values recorded, or zero if no values have been recorded.String
toString()
Returns a nonempty string representation of this object suitable for debugging.

Constructor Details

IntSummaryStatistics
public IntSummaryStatistics()Constructs an empty instance with zero count, zero sum,Integer.MAX_VALUE
min,Integer.MIN_VALUE
max and zero average. 
IntSummaryStatistics
public IntSummaryStatistics(long count, int min, int max, long sum) throws IllegalArgumentExceptionConstructs a nonempty instance with the specifiedcount
,min
,max
, andsum
.If
count
is zero then the remaining arguments are ignored and an empty instance is constructed.If the arguments are inconsistent then an
IllegalArgumentException
is thrown. The necessary consistent argument conditions are:count >= 0
min <= max
 API Note:
 The enforcement of argument correctness means that the retrieved set of
recorded values obtained from a
IntSummaryStatistics
source instance may not be a legal set of arguments for this constructor due to arithmetic overflow of the source's recorded count of values. The consistent argument conditions are not sufficient to prevent the creation of an internally inconsistent instance. An example of such a state would be an instance with:count
= 2,min
= 1,max
= 2, andsum
= 0.  Parameters:
count
 the count of valuesmin
 the minimum valuemax
 the maximum valuesum
 the sum of all values Throws:
IllegalArgumentException
 if the arguments are inconsistent Since:
 10


Method Details

accept
public void accept(int value)Records a new value into the summary information Specified by:
accept
in interfaceIntConsumer
 Parameters:
value
 the input value

combine
Combines the state of anotherIntSummaryStatistics
into this one. Parameters:
other
 anotherIntSummaryStatistics
 Throws:
NullPointerException
 ifother
is null

getCount
public final long getCount()Returns the count of values recorded. Returns:
 the count of values

getSum
public final long getSum()Returns the sum of values recorded, or zero if no values have been recorded. Returns:
 the sum of values, or zero if none

getMin
public final int getMin()Returns the minimum value recorded, orInteger.MAX_VALUE
if no values have been recorded. Returns:
 the minimum value, or
Integer.MAX_VALUE
if none

getMax
public final int getMax()Returns the maximum value recorded, orInteger.MIN_VALUE
if no values have been recorded. Returns:
 the maximum value, or
Integer.MIN_VALUE
if none

getAverage
public final double getAverage()Returns the arithmetic mean of values recorded, or zero if no values have been recorded. Returns:
 the arithmetic mean of values, or zero if none

toString
Returns a nonempty string representation of this object suitable for debugging. The exact presentation format is unspecified and may vary between implementations and versions.
