org.mongodb.morphia.aggregation

Class AggregationPipelineImpl

java.lang.Object

org.mongodb.morphia.aggregation.AggregationPipelineImpl

All Implemented Interfaces:

AggregationPipeline

public class AggregationPipelineImpl
extends Object
implements AggregationPipeline

Implementation of an AggregationPipeline.

Constructor Summary

Constructors

Constructor and Description
AggregationPipelineImpl(DatastoreImpl datastore, Class source) Creates an AggregationPipeline

Method Summary

Modifier and Type	Method and Description
<U> Iterator<U>	aggregate(Class<U> target) Executes the pipeline and aggregates the output in to the type mapped by the target type using the default options as defined in AggregationOptions.
<U> Iterator<U>	aggregate(Class<U> target, AggregationOptions options) Executes the pipeline and aggregates the output in to the type mapped by the target type.
<U> Iterator<U>	aggregate(Class<U> target, AggregationOptions options, ReadPreference readPreference) Executes the pipeline and aggregates the output in to the type mapped by the target type.
<U> Iterator<U>	aggregate(String collectionName, Class<U> target, AggregationOptions options, ReadPreference readPreference) Executes the pipeline and aggregates the output in to the type mapped by the target type.
AggregationPipeline	geoNear(GeoNear geoNear) Returns an ordered stream of documents based on the proximity to a geospatial point.
List<DBObject>	getStages() Returns the internal list of stages for this pipeline.
AggregationPipeline	group(List<Group> id, Group... groupings)
AggregationPipeline	group(String id, Group... groupings) Groups input documents by a specified identifier expression and applies the accumulator expression(s), if specified, to each group .
AggregationPipeline	limit(int count) Passes the first n documents unmodified to the pipeline where n is the specified limit.
AggregationPipeline	lookup(String from, String localField, String foreignField, String as) Performs a left outer join to an unsharded collection in the same database to filter in documents from the “joined” collection for processing.
AggregationPipeline	match(Query query) Filters the document stream to allow only matching documents to pass unmodified into the next pipeline stage.
<U> Iterator<U>	out(Class<U> target) Places the output of the aggregation in the collection mapped by the target type using the default options as defined in AggregationOptions.
<U> Iterator<U>	out(Class<U> target, AggregationOptions options) Places the output of the aggregation in the collection mapped by the target type.
<U> Iterator<U>	out(String collectionName, Class<U> target) Places the output of the aggregation in the collection mapped by the target type using the default options as defined in AggregationOptions.
<U> Iterator<U>	out(String collectionName, Class<U> target, AggregationOptions options) Places the output of the aggregation in the collection mapped by the target type.
AggregationPipeline	project(Projection... projections) Reshapes each document in the stream, such as by adding new fields or removing existing fields.
AggregationPipeline	skip(int count) Skips the first n documents where n is the specified skip number and passes the remaining documents unmodified to the pipeline.
AggregationPipeline	sort(Sort... sorts) Reorders the document stream by a specified sort key.
String	toString()
AggregationPipeline	unwind(String field) Deconstructs an array field from the input documents to output a document for each element.

Methods inherited from class java.lang.Object

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

Constructor Detail

AggregationPipelineImpl

public AggregationPipelineImpl(DatastoreImpl datastore,
                               Class source)

Creates an AggregationPipeline

Parameters:

datastore - the datastore to use

source - the source type to aggregate

Method Detail

getStages

public List<DBObject> getStages()

Returns the internal list of stages for this pipeline. This is an internal method intended only for testing and validation. Use at your own risk.

Returns:

the list of stages

aggregate

public <U> Iterator<U> aggregate(Class<U> target)

Description copied from interface: AggregationPipeline

Executes the pipeline and aggregates the output in to the type mapped by the target type using the default options as defined in AggregationOptions.

Specified by:

aggregate in interface AggregationPipeline

Type Parameters:

U - type of the results

Parameters:

target - The class to use when iterating over the results

Returns:

an iterator of the computed results

aggregate

public <U> Iterator<U> aggregate(Class<U> target,
                                 AggregationOptions options)

Description copied from interface: AggregationPipeline

Executes the pipeline and aggregates the output in to the type mapped by the target type.

Specified by:

aggregate in interface AggregationPipeline

Type Parameters:

U - type of the results

Parameters:

target - The class to use when iterating over the results

options - The options to apply to this aggregation

Returns:

an iterator of the computed results

aggregate

public <U> Iterator<U> aggregate(Class<U> target,
                                 AggregationOptions options,
                                 ReadPreference readPreference)

Description copied from interface: AggregationPipeline

Executes the pipeline and aggregates the output in to the type mapped by the target type.

Specified by:

aggregate in interface AggregationPipeline

Type Parameters:

U - type of the results

Parameters:

target - The class to use when iterating over the results

options - The options to apply to this aggregation

readPreference - The read preference to apply to this pipeline

Returns:

an iterator of the computed results

aggregate

public <U> Iterator<U> aggregate(String collectionName,
                                 Class<U> target,
                                 AggregationOptions options,
                                 ReadPreference readPreference)

Description copied from interface: AggregationPipeline

Executes the pipeline and aggregates the output in to the type mapped by the target type.

Specified by:

aggregate in interface AggregationPipeline

Type Parameters:

U - type of the results

Parameters:

collectionName - The collection in which to store the results of the aggregation overriding the mapped value in target

target - The class to use when iterating over the results

options - The options to apply to this aggregation

readPreference - The read preference to apply to this pipeline

Returns:

an iterator of the computed results

geoNear

public AggregationPipeline geoNear(GeoNear geoNear)

Description copied from interface: AggregationPipeline

Returns an ordered stream of documents based on the proximity to a geospatial point. Incorporates the functionality of $match, $sort, and $limit for geospatial data. The output documents include an additional distance field and can include a location identifier field.

Specified by:

geoNear in interface AggregationPipeline

Parameters:

geoNear - the geospatial parameters to apply to the pipeline

Returns:

this

group

public AggregationPipeline group(String id,
                                 Group... groupings)

Description copied from interface: AggregationPipeline

Groups input documents by a specified identifier expression and applies the accumulator expression(s), if specified, to each group . Consumes all input documents and outputs one document per each distinct group. The output documents only contain the identifier field and, if specified, accumulated fields.

Specified by:

group in interface AggregationPipeline

Parameters:

id - the ID of the group create

groupings - the group definitions

Returns:

this

group

public AggregationPipeline group(List<Group> id,
                                 Group... groupings)

Specified by:

group in interface AggregationPipeline

Parameters:

id - the ID of the group create

groupings - the group definitions

Returns:

this

See Also:

AggregationPipeline.group(String, Group...)

limit

public AggregationPipeline limit(int count)

Description copied from interface: AggregationPipeline

Passes the first n documents unmodified to the pipeline where n is the specified limit. For each input document, outputs either one document (for the first n documents) or zero documents (after the first n documents).

Specified by:

limit in interface AggregationPipeline

Parameters:

count - the maximum number of documents to return

Returns:

this

lookup

public AggregationPipeline lookup(String from,
                                  String localField,
                                  String foreignField,
                                  String as)

Description copied from interface: AggregationPipeline

Performs a left outer join to an unsharded collection in the same database to filter in documents from the “joined” collection for processing. The $lookup stage does an equality match between a field from the input documents with a field from the documents of the “joined” collection. To each input document, the $lookup stage adds a new array field whose elements are the matching documents from the “joined” collection. The $lookup stage passes these reshaped documents to the next stage.

Specified by:

lookup in interface AggregationPipeline

Parameters:

from - the collection to join

localField - the field from the input documents

foreignField - the field from the documents of the "from" collection

as - the output array field

Returns:

this

match

public AggregationPipeline match(Query query)

Description copied from interface: AggregationPipeline

Filters the document stream to allow only matching documents to pass unmodified into the next pipeline stage. $match uses standard MongoDB queries. For each input document, outputs either one document (a match) or zero documents (no match).

Specified by:

match in interface AggregationPipeline

Parameters:

query - the query to use when matching

Returns:

this

out

public <U> Iterator<U> out(Class<U> target)

Description copied from interface: AggregationPipeline

Places the output of the aggregation in the collection mapped by the target type using the default options as defined in AggregationOptions.

Specified by:

out in interface AggregationPipeline

Type Parameters:

U - type of the results

Parameters:

target - The class to use when iterating over the results

Returns:

an iterator of the computed results

out

public <U> Iterator<U> out(Class<U> target,
                           AggregationOptions options)

Description copied from interface: AggregationPipeline

Places the output of the aggregation in the collection mapped by the target type.

Specified by:

out in interface AggregationPipeline

Type Parameters:

U - type of the results

Parameters:

target - The class to use when iterating over the results

options - The options to apply to this aggregation

Returns:

an iterator of the computed results

out

public <U> Iterator<U> out(String collectionName,
                           Class<U> target)

Description copied from interface: AggregationPipeline

Places the output of the aggregation in the collection mapped by the target type using the default options as defined in AggregationOptions.

Specified by:

out in interface AggregationPipeline

Type Parameters:

U - type of the results

Parameters:

collectionName - The collection in which to store the results of the aggregation overriding the mapped value in target

target - The class to use when iterating over the results

Returns:

an iterator of the computed results

out

public <U> Iterator<U> out(String collectionName,
                           Class<U> target,
                           AggregationOptions options)

Description copied from interface: AggregationPipeline

Places the output of the aggregation in the collection mapped by the target type.

Specified by:

out in interface AggregationPipeline

Type Parameters:

U - type of the results

Parameters:

collectionName - The collection in which to store the results of the aggregation overriding the mapped value in target

target - The class to use when iterating over the results

options - The options to apply to this aggregation

Returns:

an iterator of the computed results

project

public AggregationPipeline project(Projection... projections)

Description copied from interface: AggregationPipeline

Reshapes each document in the stream, such as by adding new fields or removing existing fields. For each input document, outputs one document.

Specified by:

project in interface AggregationPipeline

Parameters:

projections - the projections to apply to this pipeline

Returns:

this

skip

public AggregationPipeline skip(int count)

Description copied from interface: AggregationPipeline

Skips the first n documents where n is the specified skip number and passes the remaining documents unmodified to the pipeline. For each input document, outputs either zero documents (for the first n documents) or one document (if after the first n documents).

Specified by:

skip in interface AggregationPipeline

Parameters:

count - the number of documents to skip

Returns:

this

sort

public AggregationPipeline sort(Sort... sorts)

Description copied from interface: AggregationPipeline

Reorders the document stream by a specified sort key. Only the order changes; the documents remain unmodified. For each input document, outputs one document.

Specified by:

sort in interface AggregationPipeline

Parameters:

sorts - the sorts to apply to this pipeline

Returns:

this

unwind

public AggregationPipeline unwind(String field)

Description copied from interface: AggregationPipeline

Deconstructs an array field from the input documents to output a document for each element. Each output document replaces the array with an element value. For each input document, outputs n documents where n is the number of array elements and can be zero for an empty array.

Specified by:

unwind in interface AggregationPipeline

Parameters:

field - the field to unwind

Returns:

this

toString

public String toString()

Overrides:

toString in class Object