public class LongSummaryStatistics extends java.lang.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.
Implementation Note:
This implementation is not thread safe. However, it is safe to use
Collectors.toLongStatistics()
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.
This implementation does not check for overflow of the sum.
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.
|
java.lang.String |
toString() |
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
java.lang.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 java.lang.String toString()
toString
in class java.lang.Object