redis.clients.jedis.search.aggr

Class CollectReducer

java.lang.Object

redis.clients.jedis.search.aggr.Reducer

redis.clients.jedis.search.aggr.CollectReducer

@Experimental
public final class CollectReducer
extends Reducer

Reducer for REDUCE COLLECT, which gathers per-document projections within a GROUPBY group, optionally sorted and bounded.

The grammar implemented by this reducer is:

 
 REDUCE COLLECT <narg>
     FIELDS ( * | <num_fields> <field_1> [<field_2> ...] )
     [SORTBY <narg> <@field> [ASC|DESC] [<@field> [ASC|DESC] ...]]
     [LIMIT <offset> <count>]
   [AS <alias>]
 
 

Server-side feature flag (required)

COLLECT is currently considered an unstable feature in Redis Search and is gated behind a runtime configuration switch. Callers MUST enable it on the Redis server before issuing aggregations that use this reducer; otherwise the server replies with SEARCH_QUERY_BAD `COLLECT` is unavailable when `ENABLE_UNSTABLE_FEATURES` is off.

 
 jedis.configSet("search-enable-unstable-features", "yes");
 
 

The flag can also be set permanently in redis.conf or via the matching module-load argument.

Example

 {
   @code
   AggregationBuilder agg = new AggregationBuilder().loadAll().groupBy("@color",
     Reducers.collect().fieldsAll().sortBy(SortedField.desc("@sweetness")).limit(0, 2)
         .as("top_fruits"));
 }
 

The reducer is marked Experimental because both the underlying Redis Search feature and this Java surface are subject to change while the server-side rollout is in progress.

See Also:

Reducers.collect()

Method Summary

Modifier and Type	Method and Description
CollectReducer	fields(java.lang.String... fields) Project the named fields for every document in the group.
CollectReducer	fieldsAll() Project every field available in the current input row (FIELDS *).
protected java.util.List<java.lang.Object>	getOwnArgs()
CollectReducer	limit(int count) Bound the output per group to the first count entries (offset 0).
CollectReducer	limit(int offset, int count) Bound the output per group to count entries starting at offset.
CollectReducer	sortBy(SortedField... fields) In-group sort by one or more fields.
CollectReducer	sortByAsc(java.lang.String field) Convenience for sortBy(SortedField.asc(field)).
CollectReducer	sortByDesc(java.lang.String field) Convenience for sortBy(SortedField.desc(field)).

Methods inherited from class redis.clients.jedis.search.aggr.Reducer

addArgs, as, getAlias, getField, getName

Methods inherited from class java.lang.Object

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

Method Detail

fields

public CollectReducer fields(java.lang.String... fields)

Project the named fields for every document in the group. Use @__key, @__score or document field names (e.g. @title).

Mutually exclusive with fieldsAll().

fieldsAll

public CollectReducer fieldsAll()

Project every field available in the current input row (FIELDS *).

Per the COLLECT specification, * does not trigger an implicit load — fields must already be in the pipeline (typically via LOAD * or because they are grouping keys / reducer aliases).

Mutually exclusive with fields(String...).

sortBy

public CollectReducer sortBy(SortedField... fields)

In-group sort by one or more fields. May be called multiple times to append further sort keys (each call adds to the existing list).

sortByAsc

public CollectReducer sortByAsc(java.lang.String field)

Convenience for sortBy(SortedField.asc(field)).

sortByDesc

public CollectReducer sortByDesc(java.lang.String field)

Convenience for sortBy(SortedField.desc(field)).

limit

public CollectReducer limit(int count)

Bound the output per group to the first count entries (offset 0).

limit

public CollectReducer limit(int offset,
                            int count)

Bound the output per group to count entries starting at offset.

getOwnArgs

protected java.util.List<java.lang.Object> getOwnArgs()

Specified by:

getOwnArgs in class Reducer