org.springframework.data.mongodb.core.aggregation

Class SortByCountOperation

java.lang.Object

org.springframework.data.mongodb.core.aggregation.SortByCountOperation

All Implemented Interfaces:

AggregationOperation

public class SortByCountOperation
extends Object
implements AggregationOperation

Encapsulates the aggregation framework $sortByCount-operation.

$sortByCount stage is typically used with Aggregation and $facet. Groups incoming documents based on the value of a specified expression and computes the count of documents in each distinct group. SortByCountOperation is equivalent to { $group: { _id: <expression>, count: { $sum: 1 } } }, { $sort: { count: -1 } }.

We recommend to use the static factory method Aggregation.sortByCount(String) instead of creating instances of this class directly.

Since:

2.1

Author:

Jérôme Guyon, Mark Paluch

See Also:

https://docs.mongodb.com/manual/reference/operator/aggregation/sortByCount/

Constructor Summary

Constructors

Constructor and Description
SortByCountOperation(AggregationExpression groupByExpression) Creates a new SortByCountOperation given a group-by expression.
SortByCountOperation(Field groupByField) Creates a new SortByCountOperation given a group-by field.

Method Summary

Modifier and Type	Method and Description
org.bson.Document	toDocument(AggregationOperationContext context) Turns the AggregationOperation into a Document by using the given AggregationOperationContext.

Methods inherited from class java.lang.Object

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

Constructor Detail

SortByCountOperation

public SortByCountOperation(Field groupByField)

Creates a new SortByCountOperation given a group-by field.

Parameters:

groupByField - must not be null.

SortByCountOperation

public SortByCountOperation(AggregationExpression groupByExpression)

Creates a new SortByCountOperation given a group-by expression.

Parameters:

groupByExpression - must not be null.

Method Detail

toDocument

public org.bson.Document toDocument(AggregationOperationContext context)

Description copied from interface: AggregationOperation

Turns the AggregationOperation into a Document by using the given AggregationOperationContext.

Specified by:

toDocument in interface AggregationOperation

Returns:

the Document