io.lettuce.core.search.aggregateutils

Class Reducers

java.lang.Object

io.lettuce.core.search.aggregateutils.Reducers

@Experimental
public final class Reducers
extends Object

Factory class for creating Reducer instances.

Example usage:

 
 // Count items in each group
 Reducers.count().as("item_count")

 // Sum numeric values
 Reducers.sum("@sales").as("total_sales")

 // Calculate average
 Reducers.avg("@price").as("average_price")

 // Quantile with percentile parameter
 Reducers.quantile("@price", 0.5).as("median_price")

 // First value with optional sort by
 Reducers.firstValue("@name").by("@timestamp").as("first_name")

 // Random sample
 Reducers.randomSample("@id", 10).as("sample_ids")
 
 

Since:

7.5

Author:

Aleksandar Todorov

See Also:

Reducer, ReduceFunction

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Reducers.Avg<K>
static class	Reducers.Count<K>
static class	Reducers.CountDistinct<K>
static class	Reducers.CountDistinctish<K>
static class	Reducers.FirstValue<K>
static class	Reducers.Max<K>
static class	Reducers.Min<K>
static class	Reducers.Quantile<K>
static class	Reducers.RandomSample<K>
static class	Reducers.Stddev<K>
static class	Reducers.Sum<K>
static class	Reducers.ToList<K>

Method Summary

Modifier and Type	Method and Description
static <K> Reducers.Avg<K>	avg(K field)
static <K> Reducers.Count<K>	count()
static <K> Reducers.CountDistinct<K>	countDistinct(K field)
static <K> Reducers.CountDistinctish<K>	countDistinctish(K field)
static <K> Reducers.FirstValue<K>	firstValue(K field)
static <K> Reducers.Max<K>	max(K field)
static <K> Reducers.Min<K>	min(K field)
static <K> Reducers.Quantile<K>	quantile(K field, double quantile)
static <K> Reducers.RandomSample<K>	randomSample(K field, int sampleSize)
static <K> Reducers.Stddev<K>	stddev(K field)
static <K> Reducers.Sum<K>	sum(K field)
static <K> Reducers.ToList<K>	toList(K field)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

count

public static <K> Reducers.Count<K> count()

countDistinct

public static <K> Reducers.CountDistinct<K> countDistinct(K field)

countDistinctish

public static <K> Reducers.CountDistinctish<K> countDistinctish(K field)

sum

public static <K> Reducers.Sum<K> sum(K field)

avg

public static <K> Reducers.Avg<K> avg(K field)

min

public static <K> Reducers.Min<K> min(K field)

max

public static <K> Reducers.Max<K> max(K field)

stddev

public static <K> Reducers.Stddev<K> stddev(K field)

quantile

public static <K> Reducers.Quantile<K> quantile(K field,
                                                double quantile)

toList

public static <K> Reducers.ToList<K> toList(K field)

firstValue

public static <K> Reducers.FirstValue<K> firstValue(K field)

randomSample

public static <K> Reducers.RandomSample<K> randomSample(K field,
                                                        int sampleSize)