Package com.mongodb.operation

Class MapReduceWithInlineResultsOperation<T>

java.lang.Object

com.mongodb.operation.MapReduceWithInlineResultsOperation<T>

Type Parameters:

T - the operations result type.

All Implemented Interfaces:

AsyncReadOperation<MapReduceAsyncBatchCursor<T>>, ReadOperation<MapReduceBatchCursor<T>>

public class MapReduceWithInlineResultsOperation<T>
extends Object
implements AsyncReadOperation<MapReduceAsyncBatchCursor<T>>, ReadOperation<MapReduceBatchCursor<T>>

Operation that runs a Map Reduce against a MongoDB instance. This operation only supports "inline" results, i.e. the results will be returned as a result of running this operation.

To run a map reduce operation into a given collection, use MapReduceToCollectionOperation.

Since:

3.0

MongoDB documentation

mapReduce

Map-Reduce

Constructor Summary

Constructors

Constructor	Description
MapReduceWithInlineResultsOperation(MongoNamespace namespace, BsonJavaScript mapFunction, BsonJavaScript reduceFunction, Decoder<T> decoder)	Construct a MapReduceOperation with all the criteria it needs to execute.

Method Summary

Modifier and Type	Method	Description
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.
MapReduceWithInlineResultsOperation<T>	collation(Collation collation)	Sets the collation options
MapReduceBatchCursor<T>	execute(ReadBinding binding)	Executing this will return a cursor with your results and the statistics in.
void	executeAsync(AsyncReadBinding binding, SingleResultCallback<MapReduceAsyncBatchCursor<T>> callback)	General execute which can return anything of type T
MapReduceWithInlineResultsOperation<T>	filter(BsonDocument filter)	Sets the filter to apply to the query.
MapReduceWithInlineResultsOperation<T>	finalizeFunction(BsonJavaScript finalizeFunction)	Sets the JavaScript function that follows the reduce method and modifies the output.
Collation	getCollation()	Returns the collation options
Decoder<T>	getDecoder()	Gets the decoder used to decode the result documents.
BsonDocument	getFilter()	Gets the query filter.
BsonJavaScript	getFinalizeFunction()	Gets the JavaScript function that follows the reduce method and modifies the output.
int	getLimit()	Gets the limit to apply.
BsonJavaScript	getMapFunction()	Gets the JavaScript function that associates or "maps" a value with a key and emits the key and value pair.
long	getMaxTime(TimeUnit timeUnit)	Gets the maximum execution time on the server for this operation.
MongoNamespace	getNamespace()	Gets the namespace.
BsonJavaScript	getReduceFunction()	Gets the JavaScript function that "reduces" to a single object all the values associated with a particular key.
BsonDocument	getScope()	Gets the global variables that are accessible in the map, reduce and finalize functions.
BsonDocument	getSort()	Gets the sort criteria to apply to the query.
boolean	isJsMode()	Gets the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce functions.
boolean	isVerbose()	Gets whether to include the timing information in the result information.
MapReduceWithInlineResultsOperation<T>	jsMode(boolean jsMode)	Sets the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce functions.
MapReduceWithInlineResultsOperation<T>	limit(int limit)	Sets the limit to apply.
MapReduceWithInlineResultsOperation<T>	maxTime(long maxTime, TimeUnit timeUnit)	Sets the maximum execution time on the server for this operation.
MapReduceWithInlineResultsOperation<T>	scope(BsonDocument scope)	Sets the global variables that are accessible in the map, reduce and finalize functions.
MapReduceWithInlineResultsOperation<T>	sort(BsonDocument sort)	Sets the sort criteria to apply to the query.
MapReduceWithInlineResultsOperation<T>	verbose(boolean verbose)	Sets whether to include the timing information in the result information.

Methods inherited from class java.lang.Object

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

Constructor Detail

MapReduceWithInlineResultsOperation

public MapReduceWithInlineResultsOperation(MongoNamespace namespace,
                                           BsonJavaScript mapFunction,
                                           BsonJavaScript reduceFunction,
                                           Decoder<T> decoder)

Construct a MapReduceOperation with all the criteria it needs to execute.

Parameters:

namespace - the database and collection namespace for the operation.

mapFunction - a JavaScript function that associates or "maps" a value with a key and emits the key and value pair.

reduceFunction - a JavaScript function that "reduces" to a single object all the values associated with a particular key.

decoder - the decoder for the result documents.

MongoDB documentation

mapReduce

Method Detail

getNamespace

public MongoNamespace getNamespace()

Gets the namespace.

Returns:

the namespace

Since:

3.4

getDecoder

public Decoder<T> getDecoder()

Gets the decoder used to decode the result documents.

Returns:

the decoder

Since:

3.4

getMapFunction

public BsonJavaScript getMapFunction()

Gets the JavaScript function that associates or "maps" a value with a key and emits the key and value pair.

Returns:

the JavaScript function that associates or "maps" a value with a key and emits the key and value pair.

getReduceFunction

public BsonJavaScript getReduceFunction()

Gets the JavaScript function that "reduces" to a single object all the values associated with a particular key.

Returns:

the JavaScript function that "reduces" to a single object all the values associated with a particular key.

getFinalizeFunction

public BsonJavaScript getFinalizeFunction()

Gets the JavaScript function that follows the reduce method and modifies the output. Default is null

Returns:

the JavaScript function that follows the reduce method and modifies the output.

MongoDB documentation

Requirements for the finalize Function

finalizeFunction

public MapReduceWithInlineResultsOperation<T> finalizeFunction(BsonJavaScript finalizeFunction)

Sets the JavaScript function that follows the reduce method and modifies the output.

Parameters:

finalizeFunction - the JavaScript function that follows the reduce method and modifies the output.

Returns:

this

MongoDB documentation

Requirements for the finalize Function

getScope

public BsonDocument getScope()

Gets the global variables that are accessible in the map, reduce and finalize functions.

Returns:

the global variables that are accessible in the map, reduce and finalize functions.

MongoDB documentation

Scope

scope

public MapReduceWithInlineResultsOperation<T> scope(BsonDocument scope)

Sets the global variables that are accessible in the map, reduce and finalize functions.

Parameters:

scope - the global variables that are accessible in the map, reduce and finalize functions.

Returns:

this

MongoDB documentation

mapReduce

getFilter

public BsonDocument getFilter()

Gets the query filter.

Returns:

the query filter

MongoDB documentation

Filter

filter

public MapReduceWithInlineResultsOperation<T> filter(BsonDocument filter)

Sets the filter to apply to the query.

Parameters:

filter - the filter to apply to the query.

Returns:

this

MongoDB documentation

Filter

getSort

public BsonDocument getSort()

Gets the sort criteria to apply to the query. The default is null, which means that the documents will be returned in an undefined order.

Returns:

a document describing the sort criteria

MongoDB documentation

Sort

sort

public MapReduceWithInlineResultsOperation<T> sort(BsonDocument sort)

Sets the sort criteria to apply to the query.

Parameters:

sort - the sort criteria, which may be null.

Returns:

this

MongoDB documentation

Sort

getLimit

public int getLimit()

Gets the limit to apply. The default is null.

Returns:

the limit

MongoDB documentation

Limit

limit

public MapReduceWithInlineResultsOperation<T> limit(int limit)

Sets the limit to apply.

Parameters:

limit - the limit, which may be null

Returns:

this

MongoDB documentation

Limit

isJsMode

public boolean isJsMode()

Gets the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce functions. Defaults to false.

Returns:

jsMode

MongoDB documentation

mapReduce

jsMode

public MapReduceWithInlineResultsOperation<T> jsMode(boolean jsMode)

Sets the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce functions. Defaults to false.

Parameters:

jsMode - the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce functions

Returns:

jsMode

MongoDB documentation

mapReduce

isVerbose

public boolean isVerbose()

Gets whether to include the timing information in the result information. Defaults to true.

Returns:

whether to include the timing information in the result information

verbose

public MapReduceWithInlineResultsOperation<T> verbose(boolean verbose)

Sets whether to include the timing information in the result information.

Parameters:

verbose - whether to include the timing information in the result information.

Returns:

this

getCollation

public Collation getCollation()

Returns the collation options

Returns:

the collation options

Since:

3.4

Since server release

3.4

collation

public MapReduceWithInlineResultsOperation<T> collation(Collation collation)

Sets the collation options

A null value represents the server default.

Parameters:

collation - the collation options to use

Returns:

this

Since:

3.4

Since server release

3.4

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 MapReduceWithInlineResultsOperation<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

execute

public MapReduceBatchCursor<T> execute(ReadBinding binding)

Executing this will return a cursor with your results and the statistics in.

Specified by:

execute in interface ReadOperation<T>

Parameters:

binding - the binding

Returns:

a MapReduceCursor that can be iterated over to find all the results of the Map Reduce operation.

executeAsync

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

Description copied from interface: AsyncReadOperation

General execute which can return anything of type T

Specified by:

executeAsync in interface AsyncReadOperation<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