Package org.springframework.data.mongodb.core.aggregation

Class UnionWithOperation

java.lang.Object

org.springframework.data.mongodb.core.aggregation.UnionWithOperation

All Implemented Interfaces:

AggregationOperation

public class UnionWithOperation
extends Object
implements AggregationOperation

The $unionWith aggregation stage (available since MongoDB 4.4) performs a union of two collections by combining pipeline results, potentially containing duplicates, into a single result set that is handed over to the next stage.
In order to remove duplicates it is possible to append a GroupOperation right after UnionWithOperation.
If the UnionWithOperation uses a pipeline to process documents, field names within the pipeline will be treated as is. In order to map domain type property names to actual field names (considering potential Field annotations) make sure the enclosing aggregation is a TypedAggregation and provide the target type for the $unionWith stage via mapFieldsTo(Class).

Since:

3.1

Author:

Christoph Strobl

See Also:

• Aggregation Pipeline Stage: $unionWith

Constructor Summary

Constructors

Constructor	Description
UnionWithOperation(String collection, AggregationPipeline pipeline, Class<?> domainType)

Method Summary

Modifier and Type	Method	Description
String	getOperator()	Return the MongoDB operator that is used for this AggregationOperation.
UnionWithOperation	mapFieldsTo(Class<?> domainType)	Set domain type used for field name mapping of property references used by the AggregationPipeline.
UnionWithOperation	pipeline(List<AggregationOperation> aggregationStages)	Set the aggregation pipeline stages to apply to the specified collection.
UnionWithOperation	pipeline(AggregationOperation... aggregationStages)	Set the aggregation pipeline stages to apply to the specified collection.
UnionWithOperation	pipeline(AggregationPipeline pipeline)	Set the AggregationPipeline to apply to the specified collection.
org.bson.Document	toDocument(AggregationOperationContext context)	Turns the AggregationOperation into a Document by using the given AggregationOperationContext.
static UnionWithOperation	unionWith(String collection)	Set the name of the collection from which pipeline results should be included in the result set. The collection name is used to set the coll parameter of $unionWith.

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

UnionWithOperation

public UnionWithOperation(String collection,
 @Nullable
 AggregationPipeline pipeline,
 @Nullable
 Class<?> domainType)

Method Details

unionWith

public static UnionWithOperation unionWith(String collection)

Set the name of the collection from which pipeline results should be included in the result set.
The collection name is used to set the coll parameter of $unionWith.

Parameters:

collection - the MongoDB collection name. Must not be null.

Returns:

new instance of UnionWithOperation.

Throws:

IllegalArgumentException - if the required argument is null.

pipeline

public UnionWithOperation pipeline(AggregationPipeline pipeline)

Set the AggregationPipeline to apply to the specified collection. The pipeline corresponds to the optional pipeline field of the $unionWith aggregation stage and is used to compute the documents going into the result set.

Parameters:

pipeline - the AggregationPipeline that computes the documents. Must not be null.

Returns:

new instance of UnionWithOperation.

Throws:

IllegalArgumentException - if the required argument is null.

pipeline

public UnionWithOperation pipeline(List<AggregationOperation> aggregationStages)

Set the aggregation pipeline stages to apply to the specified collection. The pipeline corresponds to the optional pipeline field of the $unionWith aggregation stage and is used to compute the documents going into the result set.

Parameters:

aggregationStages - the aggregation pipeline stages that compute the documents. Must not be null.

Returns:

new instance of UnionWithOperation.

Throws:

IllegalArgumentException - if the required argument is null.

pipeline

public UnionWithOperation pipeline(AggregationOperation... aggregationStages)

Set the aggregation pipeline stages to apply to the specified collection. The pipeline corresponds to the optional pipeline field of the $unionWith aggregation stage and is used to compute the documents going into the result set.

Parameters:

aggregationStages - the aggregation pipeline stages that compute the documents. Must not be null.

Returns:

new instance of UnionWithOperation.

Throws:

IllegalArgumentException - if the required argument is null.

mapFieldsTo

public UnionWithOperation mapFieldsTo(Class<?> domainType)

Set domain type used for field name mapping of property references used by the AggregationPipeline. Remember to also use a TypedAggregation in the outer pipeline.
If not set, field names used within pipeline operations are taken as is.

Parameters:

domainType - the domain type to map field names used in pipeline operations to. Must not be null.

Returns:

new instance of UnionWithOperation.

Throws:

IllegalArgumentException - if the required argument is null.

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.