Package com.mongodb.operation

Class MapReduceToCollectionOperation

java.lang.Object

com.mongodb.operation.MapReduceToCollectionOperation

All Implemented Interfaces:

AsyncWriteOperation<MapReduceStatistics>, WriteOperation<MapReduceStatistics>

public class MapReduceToCollectionOperation
extends java.lang.Object
implements AsyncWriteOperation<MapReduceStatistics>, WriteOperation<MapReduceStatistics>

Operation that runs a Map Reduce against a MongoDB instance. This operation does not support "inline" results, i.e. the results will be output into the collection represented by the MongoNamespace provided.

To run a map reduce operation and receive the results inline (i.e. as a response to running the command) use MapReduceToCollectionOperation.

Since:

3.0

MongoDB documentation

Map Reduce

Constructor Summary

Constructors

Constructor and Description
MapReduceToCollectionOperation(MongoNamespace namespace, BsonJavaScript mapFunction, BsonJavaScript reduceFunction, java.lang.String collectionName) Construct a MapReduceOperation with all the criteria it needs to execute
MapReduceToCollectionOperation(MongoNamespace namespace, BsonJavaScript mapFunction, BsonJavaScript reduceFunction, java.lang.String collectionName, WriteConcern writeConcern) Construct a MapReduceOperation with all the criteria it needs to execute

Method Summary

Modifier and Type	Method and Description
MapReduceToCollectionOperation	action(java.lang.String action) Sets the output action one of: "replace", "merge", "reduce"
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.
MapReduceToCollectionOperation	bypassDocumentValidation(java.lang.Boolean bypassDocumentValidation) Sets the bypass document level validation flag.
MapReduceToCollectionOperation	collation(Collation collation) Sets the collation options
MapReduceToCollectionOperation	databaseName(java.lang.String databaseName) Sets the name of the database to output into.
MapReduceStatistics	execute(WriteBinding binding) Executing this will return a cursor with your results in.
void	executeAsync(AsyncWriteBinding binding, SingleResultCallback<MapReduceStatistics> callback) General execute which can return anything of type T
MapReduceToCollectionOperation	filter(BsonDocument filter) Sets the filter to apply to the query.
MapReduceToCollectionOperation	finalizeFunction(BsonJavaScript finalizeFunction) Sets the JavaScript function that follows the reduce method and modifies the output.
java.lang.String	getAction() Gets the output action, one of: "replace", "merge", "reduce".
java.lang.Boolean	getBypassDocumentValidation() Gets the bypass document level validation flag
Collation	getCollation() Returns the collation options
java.lang.String	getCollectionName() Gets the name of the collection to output the results to.
java.lang.String	getDatabaseName() Gets the name of the database to output into.
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(java.util.concurrent.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.
WriteConcern	getWriteConcern() Gets the write concern.
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	isNonAtomic() True if the post-processing step will prevent MongoDB from locking the database.
boolean	isSharded() True if the output database is sharded
boolean	isVerbose() Gets whether to include the timing information in the result information.
MapReduceToCollectionOperation	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.
MapReduceToCollectionOperation	limit(int limit) Sets the limit to apply.
MapReduceToCollectionOperation	maxTime(long maxTime, java.util.concurrent.TimeUnit timeUnit) Sets the maximum execution time on the server for this operation.
MapReduceToCollectionOperation	nonAtomic(boolean nonAtomic) Sets if the post-processing step will prevent MongoDB from locking the database.
MapReduceToCollectionOperation	scope(BsonDocument scope) Sets the global variables that are accessible in the map, reduce and finalize functions.
MapReduceToCollectionOperation	sharded(boolean sharded) Sets if the output database is sharded
MapReduceToCollectionOperation	sort(BsonDocument sort) Sets the sort criteria to apply to the query.
MapReduceToCollectionOperation	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

MapReduceToCollectionOperation

public MapReduceToCollectionOperation(MongoNamespace namespace,
                                      BsonJavaScript mapFunction,
                                      BsonJavaScript reduceFunction,
                                      java.lang.String collectionName)

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.

collectionName - the name of the collection to output the results to.

MongoDB documentation

Map Reduce

MapReduceToCollectionOperation

public MapReduceToCollectionOperation(MongoNamespace namespace,
                                      BsonJavaScript mapFunction,
                                      BsonJavaScript reduceFunction,
                                      java.lang.String collectionName,
                                      WriteConcern writeConcern)

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.

collectionName - the name of the collection to output the results to.

writeConcern - the write concern

Since:

3.4

MongoDB documentation

Map Reduce

Method Detail

getNamespace

public MongoNamespace getNamespace()

Gets the namespace.

Returns:

the namespace

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.

getCollectionName

public java.lang.String getCollectionName()

Gets the name of the collection to output the results to.

Returns:

the name of the collection to output the results to.

getWriteConcern

public WriteConcern getWriteConcern()

Gets the write concern.

Returns:

the write concern, which may be null

Since:

3.4

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 MapReduceToCollectionOperation 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 MapReduceToCollectionOperation 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 MapReduceToCollectionOperation 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 MapReduceToCollectionOperation 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 MapReduceToCollectionOperation 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 MapReduceToCollectionOperation 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 MapReduceToCollectionOperation 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

getMaxTime

public long getMaxTime(java.util.concurrent.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 MapReduceToCollectionOperation maxTime(long maxTime,
                                              java.util.concurrent.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

getAction

public java.lang.String getAction()

Gets the output action, one of: "replace", "merge", "reduce". Defaults to "replace".

Returns:

the output action

MongoDB documentation

output with an action

action

public MapReduceToCollectionOperation action(java.lang.String action)

Sets the output action one of: "replace", "merge", "reduce"

Parameters:

action - the output action

Returns:

this

MongoDB documentation

output with an action

getDatabaseName

public java.lang.String getDatabaseName()

Gets the name of the database to output into.

Returns:

the name of the database to output into.

databaseName

public MapReduceToCollectionOperation databaseName(java.lang.String databaseName)

Sets the name of the database to output into.

Parameters:

databaseName - the name of the database to output into.

Returns:

this

MongoDB documentation

output with an action

isSharded

public boolean isSharded()

True if the output database is sharded

Returns:

true if the output database is sharded

MongoDB documentation

output with an action

sharded

public MapReduceToCollectionOperation sharded(boolean sharded)

Sets if the output database is sharded

Parameters:

sharded - if the output database is sharded

Returns:

this

MongoDB documentation

output with an action

isNonAtomic

public boolean isNonAtomic()

True if the post-processing step will prevent MongoDB from locking the database.

Returns:

if true the post-processing step will prevent MongoDB from locking the database.

MongoDB documentation

output with an action

nonAtomic

public MapReduceToCollectionOperation nonAtomic(boolean nonAtomic)

Sets if the post-processing step will prevent MongoDB from locking the database. Valid only with "merge" or "reduce" actions.

Parameters:

nonAtomic - if the post-processing step will prevent MongoDB from locking the database.

Returns:

this

MongoDB documentation

output with an action

getBypassDocumentValidation

public java.lang.Boolean getBypassDocumentValidation()

Gets the bypass document level validation flag

Returns:

the bypass document level validation flag

Since:

3.2

Since server release

3.2

bypassDocumentValidation

public MapReduceToCollectionOperation bypassDocumentValidation(java.lang.Boolean bypassDocumentValidation)

Sets the bypass document level validation flag.

Note: This only applies when an $out stage is specified

.

Parameters:

bypassDocumentValidation - If true, allows the write to opt-out of document level validation.

Returns:

this

Since:

3.2

Since server release

3.2

getCollation

public Collation getCollation()

Returns the collation options

Returns:

the collation options

Since:

3.4

Since server release

3.4

collation

public MapReduceToCollectionOperation 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

execute

public MapReduceStatistics execute(WriteBinding binding)

Executing this will return a cursor with your results in.

Specified by:

execute in interface WriteOperation<MapReduceStatistics>

Parameters:

binding - the binding

Returns:

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

executeAsync

public void executeAsync(AsyncWriteBinding binding,
                         SingleResultCallback<MapReduceStatistics> callback)

Description copied from interface: AsyncWriteOperation

General execute which can return anything of type T

Specified by:

executeAsync in interface AsyncWriteOperation<MapReduceStatistics>

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