public class LongSummaryStatistics extends Object implements LongConsumer, IntConsumer
This class is designed to work with (though does not require) streams. For example, you can compute summary statistics on a stream of longs with:
LongSummaryStatistics stats = longStream.collect(LongSummaryStatistics::new,
LongSummaryStatistics::accept,
LongSummaryStatistics::combine);
LongSummaryStatistics
can be used as a
Stream.collect(Collector) reduction}
target for a stream. For example:
LongSummaryStatistics stats = people.stream()
.collect(Collectors.summarizingLong(Person::getAge));
This computes, in a single pass, the count of people, as well as the minimum,
maximum, sum, and average of their ages.Constructor and Description |
---|
LongSummaryStatistics()
Construct an empty instance with zero count, zero sum,
Long.MAX_VALUE min, Long.MIN_VALUE max and zero
average. |
Modifier and Type | Method and Description |
---|---|
void |
accept(int value)
Records a new
int value into the summary information. |
void |
accept(long value)
Records a new
long value into the summary information. |
void |
combine(LongSummaryStatistics other)
Combines the state of another
LongSummaryStatistics 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.
|
long |
getMax()
Returns the maximum value recorded, or
Long.MIN_VALUE if no
values have been recorded |
long |
getMin()
Returns the minimum value recorded, or
Long.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 string representation of the object.
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
andThen
andThen
public LongSummaryStatistics()
Long.MAX_VALUE
min, Long.MIN_VALUE
max and zero
average.public void accept(int value)
int
value into the summary information.accept
in interface IntConsumer
value
- the input valuepublic void accept(long value)
long
value into the summary information.accept
in interface LongConsumer
value
- the input valuepublic void combine(LongSummaryStatistics other)
LongSummaryStatistics
into this
one.other
- another LongSummaryStatistics
NullPointerException
- if other
is nullpublic final long getCount()
public final long getSum()
public final long getMin()
Long.MAX_VALUE
if no
values have been recorded.Long.MAX_VALUE
if nonepublic final long getMax()
Long.MIN_VALUE
if no
values have been recordedLong.MIN_VALUE
if nonepublic final double getAverage()
public String toString()
Object
toString
method returns a string that
"textually represents" this object. The result should
be a concise but informative representation that is easy for a
person to read.
It is recommended that all subclasses override this method.
The toString
method for class Object
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `@
', and
the unsigned hexadecimal representation of the hash code of the
object. In other words, this method returns a string equal to the
value of:
getClass().getName() + '@' + Integer.toHexString(hashCode())
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