Aggregation (Spring Data MongoDB 2.1.0.RELEASE API)

java.lang.Object
- org.springframework.data.mongodb.core.aggregation.Aggregation

Direct Known Subclasses:

TypedAggregation
```
public class Aggregation
extends Object
```
An Aggregation is a representation of a list of aggregation steps to be performed by the MongoDB Aggregation Framework.

Since:

1.3

Author:

Tobias Trelle, Thomas Darimont, Oliver Gierke, Mark Paluch, Alessio Fachechi, Christoph Strobl, Nikolay Bogdanov, Gustavo de Geus, Jérôme Guyon

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`CURRENT` References the start of the field path being processed in the aggregation pipeline stage.
`static AggregationOperationContext`	`DEFAULT_CONTEXT`
`static AggregationOptions`	`DEFAULT_OPTIONS`
`protected List<AggregationOperation>`	`operations`
`static String`	`REMOVE` A variable to conditionally exclude a field.
`static String`	`ROOT` References the root document, i.e. the top-level document, currently being processed in the aggregation pipeline stage.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`Aggregation(AggregationOperation... aggregationOperations)` Creates a new `Aggregation` from the given `AggregationOperation`s.
`protected`	`Aggregation(List<AggregationOperation> aggregationOperations)` Creates a new `Aggregation` from the given `AggregationOperation`s.
`protected`	`Aggregation(List<AggregationOperation> aggregationOperations, AggregationOptions options)` Creates a new `Aggregation` from the given `AggregationOperation`s.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`protected static List<AggregationOperation>`	`asAggregationList(AggregationOperation... aggregationOperations)`
`static Fields`	`bind(String name, String target)` Creates a new `Fields` instance from the given field name and target reference.
`static BucketOperation`	`bucket(AggregationExpression groupByExpression)` Creates a new `BucketOperation` given `group-by expression`.
`static BucketOperation`	`bucket(String groupByField)` Creates a new `BucketOperation` given groupByField.
`static BucketAutoOperation`	`bucketAuto(AggregationExpression groupByExpression, int buckets)` Creates a new `BucketAutoOperation` given `group-by expression`.
`static BucketAutoOperation`	`bucketAuto(String groupByField, int buckets)` Creates a new `BucketAutoOperation` given groupByField.
`static CountOperation.CountOperationBuilder`	`count()` Creates a new `CountOperation.CountOperationBuilder`.
`static FacetOperation`	`facet()` Creates a new `FacetOperation`.
`static FacetOperation.FacetOperationBuilder`	`facet(AggregationOperation... aggregationOperations)` Creates a new `FacetOperation.FacetOperationBuilder` given `Aggregation`.
`static Fields`	`fields(String... fields)` Creates a new `Fields` instance for the given field names.
`static GeoNearOperation`	`geoNear(NearQuery query, String distanceField)` Creates a new `GeoNearOperation` instance from the given `NearQuery` and the`distanceField`.
`AggregationOptions`	`getOptions()` Get the `AggregationOptions`.
`static GraphLookupOperation.StartWithBuilder`	`graphLookup(String fromCollection)` Creates a new `GraphLookupOperation.GraphLookupOperationFromBuilder` to construct a `GraphLookupOperation` given fromCollection.
`static GroupOperation`	`group(Fields fields)` Creates a new `GroupOperation` for the given `Fields`.
`static GroupOperation`	`group(String... fields)` Creates a new `GroupOperation` for the given fields.
`static LimitOperation`	`limit(long maxElements)` Creates a new `LimitOperation` limiting the result to the given number of elements.
`static LookupOperation`	`lookup(Field from, Field localField, Field foreignField, Field as)` Creates a new `LookupOperation` for the given `Fields`.
`static LookupOperation`	`lookup(String from, String localField, String foreignField, String as)` Creates a new `LookupOperation`.
`static MatchOperation`	`match(Criteria criteria)` Creates a new `MatchOperation` using the given `Criteria`.
`static MatchOperation`	`match(CriteriaDefinition criteria)` Creates a new `MatchOperation` using the given `CriteriaDefinition`.
`static Aggregation`	`newAggregation(AggregationOperation... operations)` Creates a new `Aggregation` from the given `AggregationOperation`s.
`static <T> TypedAggregation<T>`	`newAggregation(Class<T> type, AggregationOperation... operations)` Creates a new `TypedAggregation` for the given type and `AggregationOperation`s.
`static <T> TypedAggregation<T>`	`newAggregation(Class<T> type, List<? extends AggregationOperation> operations)` Creates a new `TypedAggregation` for the given type and `AggregationOperation`s.
`static Aggregation`	`newAggregation(List<? extends AggregationOperation> operations)` Creates a new `Aggregation` from the given `AggregationOperation`s.
`static AggregationOptions.Builder`	`newAggregationOptions()` Returns a new `AggregationOptions.Builder`.
`static OutOperation`	`out(String outCollectionName)` Creates a new `OutOperation` using the given collection name.
`static String`	`previousOperation()` A pointer to the previous `AggregationOperation`.
`static ProjectionOperation`	`project(Fields fields)` Creates a new `ProjectionOperation` including the given `Fields`.
`static ProjectionOperation`	`project(String... fields)` Creates a new `ProjectionOperation` including the given fields.
`static ReplaceRootOperation.ReplaceRootOperationBuilder`	`replaceRoot()` Factory method to create a new `ReplaceRootOperation.ReplaceRootDocumentOperationBuilder` to configure a `ReplaceRootOperation`.
`static ReplaceRootOperation`	`replaceRoot(AggregationExpression aggregationExpression)` Factory method to create a new `ReplaceRootOperation` for the field with the given `AggregationExpression`.
`static ReplaceRootOperation`	`replaceRoot(String fieldName)` Factory method to create a new `ReplaceRootOperation` for the field with the given name.
`static SampleOperation`	`sample(long sampleSize)` Creates a new `SampleOperation` to select the specified number of documents from its input randomly.
`static SkipOperation`	`skip(int elementsToSkip)` Deprecated. prepare to get this one removed in favor of `skip(long)`.
`static SkipOperation`	`skip(long elementsToSkip)` Creates a new `SkipOperation` skipping the given number of elements.
`static SortOperation`	`sort(Sort.Direction direction, String... fields)` Factory method to create a new `SortOperation` for the given sort `Sort.Direction` and `fields`.
`static SortOperation`	`sort(Sort sort)` Factory method to create a new `SortOperation` for the given `Sort`.
`static SortByCountOperation`	`sortByCount(AggregationExpression groupAndSortExpression)` Creates a new `SortByCountOperation` given `group and sort expression`.
`static SortByCountOperation`	`sortByCount(String field)` Creates a new `SortByCountOperation` given groupByField.
`org.bson.Document`	`toDocument(String inputCollectionName, AggregationOperationContext rootContext)` Converts this `Aggregation` specification to a `Document`.
`List<org.bson.Document>`	`toPipeline(AggregationOperationContext rootContext)` Renders this `Aggregation` specification to an aggregation pipeline returning a `List` of `Document`.
`String`	`toString()`
`static UnwindOperation`	`unwind(String field)` Factory method to create a new `UnwindOperation` for the field with the given name.
`static UnwindOperation`	`unwind(String field, boolean preserveNullAndEmptyArrays)` Factory method to create a new `UnwindOperation` for the field with the given name and `preserveNullAndEmptyArrays`.
`static UnwindOperation`	`unwind(String field, String arrayIndex)` Factory method to create a new `UnwindOperation` for the field with the given name including the name of a new field to hold the array index of the element as `arrayIndex`.
`static UnwindOperation`	`unwind(String field, String arrayIndex, boolean preserveNullAndEmptyArrays)` Factory method to create a new `UnwindOperation` for the field with the given nameincluding the name of a new field to hold the array index of the element as `arrayIndex` using `preserveNullAndEmptyArrays`.
`Aggregation`	`withOptions(AggregationOptions options)` Returns a copy of this `Aggregation` with the given `AggregationOptions` set.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - ROOT
```
public static final String ROOT
```
    References the root document, i.e. the top-level document, currently being processed in the aggregation pipeline stage.
  - CURRENT
```
public static final String CURRENT
```
    References the start of the field path being processed in the aggregation pipeline stage. Unless documented otherwise, all stages start with CURRENT the same as ROOT.
  - REMOVE
```
public static final String REMOVE
```
    A variable to conditionally exclude a field. In a $projection, a field set to the variable REMOVE is excluded from the output.
```
 

 db.books.aggregate( [
 {
     $project: {
         title: 1,
         "author.first": 1,
         "author.last" : 1,
         "author.middle": {
             $cond: {
                 if: { $eq: [ "", "$author.middle" ] },
                 then: "$$REMOVE",
                 else: "$author.middle"
             }
         }
     }
 } ] )
 
 
```
  - DEFAULT_CONTEXT
```
public static final AggregationOperationContext DEFAULT_CONTEXT
```
  - DEFAULT_OPTIONS
```
public static final AggregationOptions DEFAULT_OPTIONS
```
  - operations
```
protected final List<AggregationOperation> operations
```
- Constructor Detail
  - Aggregation
```
protected Aggregation(AggregationOperation... aggregationOperations)
```
    Creates a new Aggregation from the given AggregationOperations.
    
    Parameters:
    
    aggregationOperations - must not be null or empty.
  - Aggregation
```
protected Aggregation(List<AggregationOperation> aggregationOperations)
```
    Creates a new Aggregation from the given AggregationOperations.
    
    Parameters:
    
    aggregationOperations - must not be null or empty.
  - Aggregation
```
protected Aggregation(List<AggregationOperation> aggregationOperations,
                      AggregationOptions options)
```
    Creates a new Aggregation from the given AggregationOperations.
    
    Parameters:
    
    aggregationOperations - must not be null or empty.
    
    options - must not be null or empty.
- Method Detail
  - newAggregation
```
public static Aggregation newAggregation(List<? extends AggregationOperation> operations)
```
    Creates a new Aggregation from the given AggregationOperations.
    
    Parameters:
    
    operations - must not be null or empty.
  - newAggregation
```
public static Aggregation newAggregation(AggregationOperation... operations)
```
    Creates a new Aggregation from the given AggregationOperations.
    
    Parameters:
    
    operations - must not be null or empty.
  - withOptions
```
public Aggregation withOptions(AggregationOptions options)
```
    Returns a copy of this Aggregation with the given AggregationOptions set. Note that options are supported in MongoDB version 2.6+.
    
    Parameters:
    
    options - must not be null.
    
    Returns:
    
    Since:
    
    1.6
  - newAggregation
```
public static <T> TypedAggregation<T> newAggregation(Class<T> type,
                                                     List<? extends AggregationOperation> operations)
```
    Creates a new TypedAggregation for the given type and AggregationOperations.
    
    Parameters:
    
    type - must not be null.
    
    operations - must not be null or empty.
  - newAggregation
```
public static <T> TypedAggregation<T> newAggregation(Class<T> type,
                                                     AggregationOperation... operations)
```
    Creates a new TypedAggregation for the given type and AggregationOperations.
    
    Parameters:
    
    type - must not be null.
    
    operations - must not be null or empty.
  - asAggregationList
```
protected static List<AggregationOperation> asAggregationList(AggregationOperation... aggregationOperations)
```
    Parameters:
    
    aggregationOperations - must not be null or empty.
    
    Returns:
  - getOptions
```
public AggregationOptions getOptions()
```
    Get the AggregationOptions.
    
    Returns:
    
    never null.
    
    Since:
    
    2.1
  - previousOperation
```
public static String previousOperation()
```
    A pointer to the previous AggregationOperation.
    
    Returns:
  - project
```
public static ProjectionOperation project(String... fields)
```
    Creates a new ProjectionOperation including the given fields.
    
    Parameters:
    
    fields - must not be null.
    
    Returns:
  - project
```
public static ProjectionOperation project(Fields fields)
```
    Creates a new ProjectionOperation including the given Fields.
    
    Parameters:
    
    fields - must not be null.
    
    Returns:
  - unwind
```
public static UnwindOperation unwind(String field)
```
    Factory method to create a new UnwindOperation for the field with the given name.
    
    Parameters:
    
    field - must not be null or empty.
    
    Returns:
  - replaceRoot
```
public static ReplaceRootOperation replaceRoot(String fieldName)
```
    Factory method to create a new ReplaceRootOperation for the field with the given name.
    
    Parameters:
    
    fieldName - must not be null or empty.
    
    Returns:
    
    Since:
    
    1.10
  - replaceRoot
```
public static ReplaceRootOperation replaceRoot(AggregationExpression aggregationExpression)
```
    Factory method to create a new ReplaceRootOperation for the field with the given AggregationExpression.
    
    Parameters:
    
    aggregationExpression - must not be null.
    
    Returns:
    
    Since:
    
    1.10
  - replaceRoot
```
public static ReplaceRootOperation.ReplaceRootOperationBuilder replaceRoot()
```
    Factory method to create a new ReplaceRootOperation.ReplaceRootDocumentOperationBuilder to configure a ReplaceRootOperation.
    
    Returns:
    
    the ReplaceRootDocumentOperationBuilder.
    
    Since:
    
    1.10
  - unwind
```
public static UnwindOperation unwind(String field,
                                     boolean preserveNullAndEmptyArrays)
```
    Factory method to create a new UnwindOperation for the field with the given name and preserveNullAndEmptyArrays. Note that extended unwind is supported in MongoDB version 3.2+.
    
    Parameters:
    
    field - must not be null or empty.
    
    preserveNullAndEmptyArrays - true to output the document if path is null, missing or array is empty.
    
    Returns:
    
    new UnwindOperation
    
    Since:
    
    1.10
  - unwind
```
public static UnwindOperation unwind(String field,
                                     String arrayIndex)
```
    Factory method to create a new UnwindOperation for the field with the given name including the name of a new field to hold the array index of the element as arrayIndex. Note that extended unwind is supported in MongoDB version 3.2+.
    
    Parameters:
    
    field - must not be null or empty.
    
    arrayIndex - must not be null or empty.
    
    Returns:
    
    new UnwindOperation
    
    Since:
    
    1.10
  - unwind
```
public static UnwindOperation unwind(String field,
                                     String arrayIndex,
                                     boolean preserveNullAndEmptyArrays)
```
    Factory method to create a new UnwindOperation for the field with the given nameincluding the name of a new field to hold the array index of the element as arrayIndex using preserveNullAndEmptyArrays. Note that extended unwind is supported in MongoDB version 3.2+.
    
    Parameters:
    
    field - must not be null or empty.
    
    arrayIndex - must not be null or empty.
    
    preserveNullAndEmptyArrays - true to output the document if path is null, missing or array is empty.
    
    Returns:
    
    new UnwindOperation
    
    Since:
    
    1.10
  - group
```
public static GroupOperation group(String... fields)
```
    Creates a new GroupOperation for the given fields.
    
    Parameters:
    
    fields - must not be null.
    
    Returns:
  - group
```
public static GroupOperation group(Fields fields)
```
    Creates a new GroupOperation for the given Fields.
    
    Parameters:
    
    fields - must not be null.
    
    Returns:
  - graphLookup
```
public static GraphLookupOperation.StartWithBuilder graphLookup(String fromCollection)
```
    Creates a new GraphLookupOperation.GraphLookupOperationFromBuilder to construct a GraphLookupOperation given fromCollection.
    
    Parameters:
    
    fromCollection - must not be null or empty.
    
    Returns:
    
    Since:
    
    1.10
  - sort
```
public static SortOperation sort(Sort sort)
```
    Factory method to create a new SortOperation for the given Sort.
    
    Parameters:
    
    sort - must not be null.
    
    Returns:
  - sort
```
public static SortOperation sort(Sort.Direction direction,
                                 String... fields)
```
    Factory method to create a new SortOperation for the given sort Sort.Direction and fields.
    
    Parameters:
    
    direction - must not be null.
    
    fields - must not be null.
    
    Returns:
  - sortByCount
```
public static SortByCountOperation sortByCount(String field)
```
    Creates a new SortByCountOperation given groupByField.
    
    Parameters:
    
    field - must not be null or empty.
    
    Returns:
    
    Since:
    
    2.1
  - sortByCount
```
public static SortByCountOperation sortByCount(AggregationExpression groupAndSortExpression)
```
    Creates a new SortByCountOperation given group and sort expression.
    
    Parameters:
    
    groupAndSortExpression - must not be null.
    
    Returns:
    
    Since:
    
    2.1
  - skip
```
public static SkipOperation skip(int elementsToSkip)
```
    Deprecated. prepare to get this one removed in favor of skip(long).
    
    Creates a new SkipOperation skipping the given number of elements.
    
    Parameters:
    
    elementsToSkip - must not be less than zero.
    
    Returns:
  - skip
```
public static SkipOperation skip(long elementsToSkip)
```
    Creates a new SkipOperation skipping the given number of elements.
    
    Parameters:
    
    elementsToSkip - must not be less than zero.
    
    Returns:
  - limit
```
public static LimitOperation limit(long maxElements)
```
    Creates a new LimitOperation limiting the result to the given number of elements.
    
    Parameters:
    
    maxElements - must not be less than zero.
    
    Returns:
  - sample
```
public static SampleOperation sample(long sampleSize)
```
    Creates a new SampleOperation to select the specified number of documents from its input randomly.
    
    Parameters:
    
    sampleSize - must not be less than zero.
    
    Returns:
    
    Since:
    
    2.0
  - match
```
public static MatchOperation match(Criteria criteria)
```
    Creates a new MatchOperation using the given Criteria.
    
    Parameters:
    
    criteria - must not be null.
    
    Returns:
  - match
```
public static MatchOperation match(CriteriaDefinition criteria)
```
    Creates a new MatchOperation using the given CriteriaDefinition.
    
    Parameters:
    
    criteria - must not be null.
    
    Returns:
    
    Since:
    
    1.10
  - out
```
public static OutOperation out(String outCollectionName)
```
    Creates a new OutOperation using the given collection name. This operation must be the last operation in the pipeline.
    
    Parameters:
    
    outCollectionName - collection name to export aggregation results. The OutOperation creates a new collection in the current database if one does not already exist. The collection is not visible until the aggregation completes. If the aggregation fails, MongoDB does not create the collection. Must not be null.
    
    Returns:
  - bucket
```
public static BucketOperation bucket(String groupByField)
```
    Creates a new BucketOperation given groupByField.
    
    Parameters:
    
    groupByField - must not be null or empty.
    
    Returns:
    
    Since:
    
    1.10
  - bucket
```
public static BucketOperation bucket(AggregationExpression groupByExpression)
```
    Creates a new BucketOperation given group-by expression.
    
    Parameters:
    
    groupByExpression - must not be null.
    
    Returns:
    
    Since:
    
    1.10
  - bucketAuto
```
public static BucketAutoOperation bucketAuto(String groupByField,
                                             int buckets)
```
    Creates a new BucketAutoOperation given groupByField.
    
    Parameters:
    
    groupByField - must not be null or empty.
    
    buckets - number of buckets, must be a positive integer.
    
    Returns:
    
    Since:
    
    1.10
  - bucketAuto
```
public static BucketAutoOperation bucketAuto(AggregationExpression groupByExpression,
                                             int buckets)
```
    Creates a new BucketAutoOperation given group-by expression.
    
    Parameters:
    
    groupByExpression - must not be null.
    
    buckets - number of buckets, must be a positive integer.
    
    Returns:
    
    Since:
    
    1.10
  - facet
```
public static FacetOperation facet()
```
    Creates a new FacetOperation.
    
    Returns:
    
    Since:
    
    1.10
  - facet
```
public static FacetOperation.FacetOperationBuilder facet(AggregationOperation... aggregationOperations)
```
    Creates a new FacetOperation.FacetOperationBuilder given Aggregation.
    
    Parameters:
    
    aggregationOperations - the sub-pipeline, must not be null.
    
    Returns:
    
    Since:
    
    1.10
  - lookup
```
public static LookupOperation lookup(String from,
                                     String localField,
                                     String foreignField,
                                     String as)
```
    Creates a new LookupOperation.
    
    Parameters:
    
    from - must not be null.
    
    localField - must not be null.
    
    foreignField - must not be null.
    
    as - must not be null.
    
    Returns:
    
    never null.
    
    Since:
    
    1.9
  - lookup
```
public static LookupOperation lookup(Field from,
                                     Field localField,
                                     Field foreignField,
                                     Field as)
```
    Creates a new LookupOperation for the given Fields.
    
    Parameters:
    
    from - must not be null.
    
    localField - must not be null.
    
    foreignField - must not be null.
    
    as - must not be null.
    
    Returns:
    
    never null.
    
    Since:
    
    1.9
  - count
```
public static CountOperation.CountOperationBuilder count()
```
    Creates a new CountOperation.CountOperationBuilder.
    
    Returns:
    
    never null.
    
    Since:
    
    1.10
  - fields
```
public static Fields fields(String... fields)
```
    Creates a new Fields instance for the given field names.
    
    Parameters:
    
    fields - must not be null.
    
    Returns:
    
    See Also:
    
    Fields.fields(String...)
  - bind
```
public static Fields bind(String name,
                          String target)
```
    Creates a new Fields instance from the given field name and target reference.
    
    Parameters:
    
    name - must not be null or empty.
    
    target - must not be null or empty.
    
    Returns:
  - geoNear
```
public static GeoNearOperation geoNear(NearQuery query,
                                       String distanceField)
```
    Creates a new GeoNearOperation instance from the given NearQuery and thedistanceField. The distanceField defines output field that contains the calculated distance.
    
    Parameters:
    
    query - must not be null.
    
    distanceField - must not be null or empty.
    
    Returns:
    
    Since:
    
    1.7
  - newAggregationOptions
```
public static AggregationOptions.Builder newAggregationOptions()
```
    Returns a new AggregationOptions.Builder.
    
    Returns:
    
    Since:
    
    1.6
  - toPipeline
```
public List<org.bson.Document> toPipeline(AggregationOperationContext rootContext)
```
    Renders this Aggregation specification to an aggregation pipeline returning a List of Document.
    
    Returns:
    
    the aggregation pipeline representing this aggregation.
    
    Since:
    
    2.1
  - toDocument
```
public org.bson.Document toDocument(String inputCollectionName,
                                    AggregationOperationContext rootContext)
```
    Converts this Aggregation specification to a Document.
    MongoDB requires as of 3.6 cursor-based aggregation. Use toPipeline(AggregationOperationContext) to render an aggregation pipeline.
    
    Parameters:
    
    inputCollectionName - the name of the input collection.
    
    Returns:
    
    the Document representing this aggregation.
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class Aggregation

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ROOT

CURRENT

REMOVE

DEFAULT_CONTEXT

DEFAULT_OPTIONS

operations

Constructor Detail

Aggregation

Aggregation

Aggregation

Method Detail

newAggregation

newAggregation

withOptions

newAggregation

newAggregation

asAggregationList

getOptions

previousOperation

project

project

unwind

replaceRoot

replaceRoot

replaceRoot

unwind

unwind

unwind

group

group

graphLookup

sort

sort

sortByCount

sortByCount

skip

skip

limit

sample

match

match

out

bucket

bucket

bucketAuto

bucketAuto

facet

facet

lookup

lookup

count

fields

bind

geoNear

newAggregationOptions

toPipeline

toDocument

toString