Package 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	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	Description
String	getOperator()	Return the MongoDB operator that is used for this AggregationOperation.
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

Methods inherited from interface org.springframework.data.mongodb.core.aggregation.AggregationOperation

toPipelineStages

Constructor Details

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 Details

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

Parameters:

context - the AggregationOperationContext to operate within. Must not be null.

Returns:

the Document

getOperator

public String getOperator()

Description copied from interface: AggregationOperation

Return the MongoDB operator that is used for this AggregationOperation. Aggregation operations should implement this method to avoid document rendering.

Specified by:

getOperator in interface AggregationOperation

Returns:

the operator used for this AggregationOperation.