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.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.
|
String |
toString()
Returns a string representation of the object.
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, waitandThenandThenpublic 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 IntConsumervalue - the input valuepublic void accept(long value)
long value into the summary information.accept in interface LongConsumervalue - the input valuepublic void combine(LongSummaryStatistics other)
LongSummaryStatistics into this
one.other - another LongSummaryStatisticsNullPointerException - 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()
ObjecttoString 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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