io.lettuce.core.search.arguments

Class AggregateArgs.GroupBy<K,V>

java.lang.Object

io.lettuce.core.search.arguments.AggregateArgs.GroupBy<K,V>

All Implemented Interfaces:

AggregateArgs.PipelineOperation<K,V>

Enclosing class:

AggregateArgs<K,V>

public static class AggregateArgs.GroupBy<K,V>
extends Object
implements AggregateArgs.PipelineOperation<K,V>

Represents a GROUPBY clause in an aggregation pipeline.

Groups the results in the pipeline based on one or more properties. Each group should have at least one reducer function that handles the group entries, either counting them or performing multiple aggregate operations.

Example Usage:

 {
     @code
     // Group by category and count items
     GroupBy groupBy = GroupBy.of("category").reduce(Reducer.count().as("item_count"));

     // Group by multiple fields with multiple reducers
     GroupBy complexGroup = GroupBy.of("category", "brand").reduce(Reducer.count().as("count"))
             .reduce(Reducer.avg("@price").as("avg_price")).reduce(Reducer.sum("@quantity").as("total_quantity"));
 }
 

Supported Reducers:

• COUNT - Count the number of records in each group
• SUM - Sum numeric values within each group
• AVG - Calculate average of numeric values
• MIN/MAX - Find minimum/maximum values
• COUNT_DISTINCT - Count distinct values

Performance Note: Properties used in GROUPBY should be stored as SORTABLE in the index for optimal performance.

Constructor Summary

Constructors

Constructor and Description
GroupBy(List<K> properties)

Method Summary

Modifier and Type	Method and Description
void	build(CommandArgs<K,V> args) Build the operation arguments into the command args.
static <K,V> AggregateArgs.GroupBy<K,V>	of(K... properties) Static factory method to create a GroupBy instance.
AggregateArgs.GroupBy<K,V>	reduce(AggregateArgs.Reducer<K,V> reducer)

Methods inherited from class java.lang.Object

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

Constructor Detail

GroupBy

public GroupBy(List<K> properties)

Method Detail

reduce

public AggregateArgs.GroupBy<K,V> reduce(AggregateArgs.Reducer<K,V> reducer)

of

@SafeVarargs
public static <K,V> AggregateArgs.GroupBy<K,V> of(K... properties)

Static factory method to create a GroupBy instance.

Type Parameters:

K - Key type

V - Value type

Parameters:

properties - the properties to group by

Returns:

new GroupBy instance

build

public void build(CommandArgs<K,V> args)

Description copied from interface: AggregateArgs.PipelineOperation

Build the operation arguments into the command args.

Specified by:

build in interface AggregateArgs.PipelineOperation<K,V>

Parameters:

args - the command args to build into