KtMongo: MongoDB request DSL/opensavvy.ktmongo.dsl.aggregation/AggregationPipeline

AggregationPipeline

interface AggregationPipeline<Document : Any> : Pipeline<Document> , HasCount<Document> , HasGroup<Document> , HasLimit<Document> , HasLookup<Document> , HasLookupPipelineCompatibility<Document> , HasMatch<Document> , HasProject<Document> , HasSample<Document> , HasSet<Document> , HasSkip<Document> , HasSort<Document> , HasUnionWith<Document> , HasUnionWithCompatibility<Document> , HasUnset<Document> (source)

An aggregation pipeline.

Aggregation pipelines read data from one or more collections and transform it in a manner of ways. Finally, the data can be sent to the server, or written to another collection.

Example

invoices.aggregate()
    .match { Invoice::isDraft eq false }
    .set {
        Invoice::anomaly set (of(Invoice::modificationDate) lt of(Invoice::creationDate))
    }
    .sort { ascending(Invoice::creationDate) }
    .toList()

External resources

Official documentation

Properties

abstract val context: BsonContext

The context used to generate this pipeline.

Functions

open fun <Output : Any> countTo(field: KProperty1<Output, Number>): Pipeline<Output>

open fun <Output : Any> countTo(field: Field<Output, Number>): Pipeline<Output>

Counts how many elements exist in the pipeline and outputs a single document containing a single field containing the count.

abstract fun embedInLookup(writer: BsonFieldWriter)

Writes this pipeline's contribution into a $lookup stage.

embedInUnionWith

abstract fun embedInUnionWith(writer: BsonFieldWriter)

Writes this pipeline into a $unionWith stage.

open fun <Out : Any> group(block: GroupStageOperators<Document, Out>.() -> Unit): Pipeline<Out>

Combines many documents into few documents.

open fun limit(amount: Int): Pipeline<Document>

open fun limit(amount: Long): Pipeline<Document>

Limits the number of elements passed to the next stage to amount.

open fun <ForeignDocument : Any> lookup(block: LookupStageOperators<Document, ForeignDocument>.() -> Unit): Pipeline<Document>

Performs an equality match join between this collection and another collection.

open fun match(filter: FilterQuery<Document>.() -> Unit): Pipeline<Document>

Filters documents based on a specified filter.

open fun matchExpr(filter: AggregationOperators.() -> Value<Document, Boolean>): Pipeline<Document>

Filters documents based on a specific filter, written using aggregation syntax.

open fun project(block: ProjectStageOperators<Document>.() -> Unit): Pipeline<Document>

Specifies a list of fields which should be kept in the document.

@DangerousMongoApi

abstract fun <New : Any> reinterpret(): Pipeline<New>

Changes the type of the returned document, with no type-safety.

open fun sample(size: Int): Pipeline<Document>

Randomly selects size documents.

open fun set(block: SetStageOperators<Document>.() -> Unit): Pipeline<Document>

Adds new fields to documents, or overwrites existing fields.

open fun skip(amount: Int): Pipeline<Document>

open fun skip(amount: Long): Pipeline<Document>

Skips over the specified amount of documents that pass into the stage, and passes the remaining documents to the next stage.

open fun sort(block: SortOptionDsl<Document>.() -> Unit): Pipeline<Document>

Specifies in which order elements should be sorted.

abstract override fun toString(): String

JSON representation of this pipeline.

open fun unionWith(other: HasUnionWithCompatibility<Document>): Pipeline<Document>

Combines two aggregations into a single result set.

open fun unset(block: UnsetStageOperators<Document>.() -> Unit): Pipeline<Document>

Removes fields from documents.

@DangerousMongoApi

abstract fun withStage(stage: BsonNode): Pipeline<Document>

Creates a new pipeline that expands on the current one by adding stage.

abstract fun writeTo(writer: BsonValueWriter)

Writes the entire pipeline into writer.