Class LongSummaryStatistics
 java.lang.Object

 java.util.LongSummaryStatistics
 All Implemented Interfaces:

IntConsumer
,LongConsumer
public class LongSummaryStatistics extends Object implements LongConsumer, 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 longs with:
LongSummaryStatistics stats = longStream.collect(LongSummaryStatistics::new, LongSummaryStatistics::accept, LongSummaryStatistics::combine);
LongSummaryStatistics
can be used as a 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.summarizingLong()
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
Constructor  Description 

LongSummaryStatistics()  Constructs an empty instance with zero count, zero sum, 
LongSummaryStatistics(long count,
long min,
long max,
long sum)  Constructs a nonempty instance with the specified 
Method Summary
Modifier and Type  Method  Description 

void  accept(int value)  Records a new 
void  accept(long value)  Records a new 
void  combine(LongSummaryStatistics other)  Combines the state of another 
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  getMin()  Returns the minimum value recorded, or 
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. 
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods declared in interface java.util.function.IntConsumer
andThen
Methods declared in interface java.util.function.LongConsumer
andThen
Constructor Detail
LongSummaryStatistics
public LongSummaryStatistics()
Constructs an empty instance with zero count, zero sum, Long.MAX_VALUE
min, Long.MIN_VALUE
max and zero average.
LongSummaryStatistics
public LongSummaryStatistics(long count, long min, long max, long sum) throws IllegalArgumentException
Constructs a nonempty 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
LongSummaryStatistics
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 values 
min
 the minimum value 
max
 the maximum value 
sum
 the sum of all values  Throws:

IllegalArgumentException
 if the arguments are inconsistent  Since:
 10
Method Detail
accept
public void accept(int value)
Records a new int
value into the summary information.
 Specified by:

accept
in interfaceIntConsumer
 Parameters:

value
 the input value
accept
public void accept(long value)
Records a new long
value into the summary information.
 Specified by:

accept
in interfaceLongConsumer
 Parameters:

value
 the input value
combine
public void combine(LongSummaryStatistics other)
Combines the state of another LongSummaryStatistics
into this one.
 Parameters:

other
 anotherLongSummaryStatistics
 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 long getMin()
Returns the minimum value recorded, or Long.MAX_VALUE
if no values have been recorded.
 Returns:
 the minimum value, or
Long.MAX_VALUE
if none
getMax
public final long getMax()
Returns the maximum value recorded, or Long.MIN_VALUE
if no values have been recorded
 Returns:
 the maximum value, or
Long.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
public String 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.