com.mongodb.operation

Class AggregateOperation<T>

java.lang.Object

com.mongodb.operation.AggregateOperation<T>

Type Parameters:

T - the operations result type.

All Implemented Interfaces:

AsyncReadOperation<AsyncBatchCursor<T>>, ReadOperation<BatchCursor<T>>

public class AggregateOperation<T>
extends Object
implements AsyncReadOperation<AsyncBatchCursor<T>>, ReadOperation<BatchCursor<T>>

An operation that executes an aggregation query.

Since:

3.0

MongoDB documentation

Aggregation

Since server release

2.2

Constructor Summary

Constructors

Constructor and Description
AggregateOperation(MongoNamespace namespace, List<BsonDocument> pipeline, Decoder<T> decoder) Construct a new instance.

Method Summary

Methods

Modifier and Type	Method and Description
AggregateOperation<T>	allowDiskUse(Boolean allowDiskUse) Enables writing to temporary files.
ReadOperation<BsonDocument>	asExplainableOperation(ExplainVerbosity explainVerbosity) Gets an operation whose execution explains this operation.
AsyncReadOperation<BsonDocument>	asExplainableOperationAsync(ExplainVerbosity explainVerbosity) Gets an operation whose execution explains this operation.
AggregateOperation<T>	batchSize(Integer batchSize) Sets the number of documents to return per batch.
BatchCursor<T>	execute(ReadBinding binding) General execute which can return anything of type T
void	executeAsync(AsyncReadBinding binding, SingleResultCallback<AsyncBatchCursor<T>> callback) General execute which can return anything of type T
Boolean	getAllowDiskUse() Whether writing to temporary files is enabled.
Integer	getBatchSize() Gets the number of documents to return per batch.
long	getMaxTime(TimeUnit timeUnit) Gets the maximum execution time on the server for this operation.
List<BsonDocument>	getPipeline() Gets the aggregation pipeline.
Boolean	getUseCursor() Gets whether the server should use a cursor to return results.
AggregateOperation<T>	maxTime(long maxTime, TimeUnit timeUnit) Sets the maximum execution time on the server for this operation.
AggregateOperation<T>	useCursor(Boolean useCursor) Sets whether the server should use a cursor to return results.

Methods inherited from class java.lang.Object

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

Constructor Detail

AggregateOperation

public AggregateOperation(MongoNamespace namespace,
                  List<BsonDocument> pipeline,
                  Decoder<T> decoder)

Construct a new instance.

Parameters:

namespace - the database and collection namespace for the operation.

pipeline - the aggregation pipeline.

decoder - the decoder for the result documents.

Method Detail

getPipeline

public List<BsonDocument> getPipeline()

Gets the aggregation pipeline.

Returns:

the pipeline

MongoDB documentation

Aggregation Pipeline

getAllowDiskUse

public Boolean getAllowDiskUse()

Whether writing to temporary files is enabled. A null value indicates that it's unspecified.

Returns:

true if writing to temporary files is enabled

MongoDB documentation

Aggregation

Since server release

2.6

allowDiskUse

public AggregateOperation<T> allowDiskUse(Boolean allowDiskUse)

Enables writing to temporary files. A null value indicates that it's unspecified.

Parameters:

allowDiskUse - true if writing to temporary files is enabled

Returns:

this

MongoDB documentation

Aggregation

Since server release

2.6

getBatchSize

public Integer getBatchSize()

Gets the number of documents to return per batch. Default to 0, which indicates that the server chooses an appropriate batch size.

Returns:

the batch size, which may be null

MongoDB documentation

Batch Size

batchSize

public AggregateOperation<T> batchSize(Integer batchSize)

Sets the number of documents to return per batch.

Parameters:

batchSize - the batch size

Returns:

this

MongoDB documentation

Batch Size

getMaxTime

public long getMaxTime(TimeUnit timeUnit)

Gets the maximum execution time on the server for this operation. The default is 0, which places no limit on the execution time.

Parameters:

timeUnit - the time unit to return the result in

Returns:

the maximum execution time in the given time unit

MongoDB documentation

Max Time

maxTime

public AggregateOperation<T> maxTime(long maxTime,
                            TimeUnit timeUnit)

Sets the maximum execution time on the server for this operation.

Parameters:

maxTime - the max time

timeUnit - the time unit, which may not be null

Returns:

this

MongoDB documentation

Max Time

getUseCursor

public Boolean getUseCursor()

Gets whether the server should use a cursor to return results. The default value is null, in which case a cursor will be used if the server supports it.

Returns:

whether the server should use a cursor to return results

MongoDB documentation

Aggregation

Since server release

2.6

useCursor

public AggregateOperation<T> useCursor(Boolean useCursor)

Sets whether the server should use a cursor to return results.

Parameters:

useCursor - whether the server should use a cursor to return results

Returns:

this

MongoDB documentation

Aggregation

Since server release

2.6

execute

public BatchCursor<T> execute(ReadBinding binding)

Description copied from interface: ReadOperation

General execute which can return anything of type T

Specified by:

execute in interface ReadOperation<BatchCursor<T>>

Parameters:

binding - the binding to execute in the context of

Returns:

T, the result of the execution

executeAsync

public void executeAsync(AsyncReadBinding binding,
                SingleResultCallback<AsyncBatchCursor<T>> callback)

Description copied from interface: AsyncReadOperation

General execute which can return anything of type T

Specified by:

executeAsync in interface AsyncReadOperation<AsyncBatchCursor<T>>

Parameters:

binding - the binding to execute in the context of

callback - the callback to be called when the operation has been executed

asExplainableOperation

public ReadOperation<BsonDocument> asExplainableOperation(ExplainVerbosity explainVerbosity)

Gets an operation whose execution explains this operation.

Parameters:

explainVerbosity - the explain verbosity

Returns:

a read operation that when executed will explain this operation

asExplainableOperationAsync

public AsyncReadOperation<BsonDocument> asExplainableOperationAsync(ExplainVerbosity explainVerbosity)

Gets an operation whose execution explains this operation.

Parameters:

explainVerbosity - the explain verbosity

Returns:

a read operation that when executed will explain this operation