IntSummaryStatistics
public
class
IntSummaryStatistics
extends Object
implements
IntConsumer
java.lang.Object | |
↳ | java.util.IntSummaryStatistics |
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));
Summary
Public constructors | |
---|---|
IntSummaryStatistics()
Constructs an empty instance with zero count, zero sum,
|
|
IntSummaryStatistics(long count, int min, int max, long sum)
Constructs a non-empty instance with the specified |
Public methods | |
---|---|
void
|
accept(int value)
Records a new value into the summary information |
void
|
combine(IntSummaryStatistics other)
Combines the state of another |
final
double
|
getAverage()
Returns the arithmetic mean of values recorded, or zero if no values have been recorded. |
final
long
|
getCount()
Returns the count of values recorded. |
final
int
|
getMax()
Returns the maximum value recorded, or |
final
int
|
getMin()
Returns the minimum value recorded, or |
final
long
|
getSum()
Returns the sum of values recorded, or zero if no values have been recorded. |
String
|
toString()
Returns a non-empty string representation of this object suitable for debugging. |
Inherited methods | |
---|---|
Public constructors
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)
Constructs a non-empty instance with the specified count
,
min
, max
, and sum
.
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 |
long : the count of values |
min |
int : the minimum value |
max |
int : the maximum value |
sum |
long : the sum of all values |
Throws | |
---|---|
IllegalArgumentException |
if the arguments are inconsistent |
Public methods
accept
public void accept (int value)
Records a new value into the summary information
Parameters | |
---|---|
value |
int : the input value |
combine
public void combine (IntSummaryStatistics other)
Combines the state of another IntSummaryStatistics
into this one.
Parameters | |
---|---|
other |
IntSummaryStatistics : another IntSummaryStatistics |
Throws | |
---|---|
NullPointerException |
if other is null |
getAverage
public final double getAverage ()
Returns the arithmetic mean of values recorded, or zero if no values have been recorded.
Returns | |
---|---|
double |
the arithmetic mean of values, or zero if none |
getCount
public final long getCount ()
Returns the count of values recorded.
Returns | |
---|---|
long |
the count of values |
getMax
public final int getMax ()
Returns the maximum value recorded, or Integer.MIN_VALUE
if no
values have been recorded.
Returns | |
---|---|
int |
the maximum value, or Integer.MIN_VALUE if none |
getMin
public final int getMin ()
Returns the minimum value recorded, or Integer.MAX_VALUE
if no
values have been recorded.
Returns | |
---|---|
int |
the minimum value, or Integer.MAX_VALUE if none |
getSum
public final long getSum ()
Returns the sum of values recorded, or zero if no values have been recorded.
Returns | |
---|---|
long |
the sum of values, or zero if none |
toString
public String toString ()
Returns a non-empty string representation of this object suitable for debugging. The exact presentation format is unspecified and may vary between implementations and versions.
Returns | |
---|---|
String |
a string representation of the object. |