com.mongodb

Class MapReduceCommand

java.lang.Object

com.mongodb.MapReduceCommand

public class MapReduceCommand
extends Object

This class groups the argument for a map/reduce operation and can build the underlying command object

MongoDB documentation

Map-Reduce

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MapReduceCommand.OutputType Represents the different options available for outputting the results of a map-reduce operation.

Constructor Summary

Constructors

Constructor and Description
MapReduceCommand(DBCollection inputCollection, String map, String reduce, String outputCollection, MapReduceCommand.OutputType type, DBObject query) Represents the command for a map reduce operation Runs the command in REPLACE output type to a named collection

Method Summary

Modifier and Type	Method and Description
Boolean	getBypassDocumentValidation() Gets whether to bypass document validation, or null if unspecified.
Collation	getCollation() Returns the collation
String	getFinalize() Gets the Finalize JS Function
String	getInput() Get the name of the collection the MapReduce will read from
Boolean	getJsMode() Gets the (optional) JavaScript mode
int	getLimit() Gets the (optional) limit on input
String	getMap() Get the map function, as a JS String
long	getMaxTime(TimeUnit timeUnit) Gets the max execution time for this command, in the given time unit.
String	getOutputDB() Gets the (optional) database name where the output collection should reside
String	getOutputTarget() Gets the output target (name of collection to save to) This value is nullable only if OutputType is set to INLINE
MapReduceCommand.OutputType	getOutputType() Gets the OutputType for this instance.
DBObject	getQuery() Gets the query to run for this MapReduce job
ReadPreference	getReadPreference() Gets the read preference
String	getReduce() Gets the reduce function, as a JS String
Map<String,Object>	getScope() Gets the (optional) JavaScript scope
DBObject	getSort() Gets the (optional) sort specification object
Boolean	isVerbose() Gets the verbosity of the MapReduce job.
void	setBypassDocumentValidation(Boolean bypassDocumentValidation) Sets whether to bypass document validation.
void	setCollation(Collation collation) Sets the collation options
void	setFinalize(String finalize) Sets the Finalize JS Function
void	setJsMode(Boolean jsMode) Sets the (optional) JavaScript Mode
void	setLimit(int limit) Sets the (optional) limit on input
void	setMaxTime(long maxTime, TimeUnit timeUnit) Sets the max execution time for this command, in the given time unit.
void	setOutputDB(String outputDB) Sets the (optional) database name where the output collection should reside
void	setReadPreference(ReadPreference preference) Sets the read preference for this command.
void	setScope(Map<String,Object> scope) Sets the (optional) JavaScript scope
void	setSort(DBObject sort) Sets the (optional) sort specification object
void	setVerbose(Boolean verbose) Sets the verbosity of the MapReduce job, defaults to 'true'
DBObject	toDBObject() Turns this command into a DBObject representation of this map reduce command.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

MapReduceCommand

public MapReduceCommand(DBCollection inputCollection,
                        String map,
                        String reduce,
                        String outputCollection,
                        MapReduceCommand.OutputType type,
                        DBObject query)

Represents the command for a map reduce operation Runs the command in REPLACE output type to a named collection

Parameters:

inputCollection - collection to use as the source documents to perform the map reduce operation.

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

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

outputCollection - optional - leave null if want to get the result inline

type - the type of output

query - specifies the selection criteria using query operators for determining the documents input to the map function.

MongoDB documentation

Map Reduce Command

Method Detail

setVerbose

public void setVerbose(Boolean verbose)

Sets the verbosity of the MapReduce job, defaults to 'true'

Parameters:

verbose - The verbosity level.

isVerbose

public Boolean isVerbose()

Gets the verbosity of the MapReduce job.

Returns:

the verbosity level.

getInput

public String getInput()

Get the name of the collection the MapReduce will read from

Returns:

name of the collection the MapReduce will read from

getMap

public String getMap()

Get the map function, as a JS String

Returns:

the map function (as a JS String)

getReduce

public String getReduce()

Gets the reduce function, as a JS String

Returns:

the reduce function (as a JS String)

getOutputTarget

public String getOutputTarget()

Gets the output target (name of collection to save to) This value is nullable only if OutputType is set to INLINE

Returns:

The outputCollection

getOutputType

public MapReduceCommand.OutputType getOutputType()

Gets the OutputType for this instance.

Returns:

The outputType.

getFinalize

public String getFinalize()

Gets the Finalize JS Function

Returns:

The finalize function (as a JS String).

setFinalize

public void setFinalize(String finalize)

Sets the Finalize JS Function

Parameters:

finalize - The finalize function (as a JS String)

getQuery

public DBObject getQuery()

Gets the query to run for this MapReduce job

Returns:

The query object

getSort

public DBObject getSort()

Gets the (optional) sort specification object

Returns:

the Sort DBObject

setSort

public void setSort(DBObject sort)

Sets the (optional) sort specification object

Parameters:

sort - The sort specification object

getLimit

public int getLimit()

Gets the (optional) limit on input

Returns:

The limit specification object

setLimit

public void setLimit(int limit)

Sets the (optional) limit on input

Parameters:

limit - The limit specification object

getMaxTime

public long getMaxTime(TimeUnit timeUnit)

Gets the max execution time for this command, in the given time unit.

Parameters:

timeUnit - the time unit to return the value in.

Returns:

the maximum execution time

Since:

2.12.0

Since server release

2.6

setMaxTime

public void setMaxTime(long maxTime,
                       TimeUnit timeUnit)

Sets the max execution time for this command, in the given time unit.

Parameters:

maxTime - the maximum execution time. A non-zero value requires a server version >= 2.6

timeUnit - the time unit that maxTime is specified in

Since:

2.12.0

Since server release

2.6

getScope

public Map<String,Object> getScope()

Gets the (optional) JavaScript scope

Returns:

The JavaScript scope

setScope

public void setScope(Map<String,Object> scope)

Sets the (optional) JavaScript scope

Parameters:

scope - The JavaScript scope

getJsMode

public Boolean getJsMode()

Gets the (optional) JavaScript mode

Returns:

The JavaScript mode

Since:

2.13

setJsMode

public void setJsMode(Boolean jsMode)

Sets the (optional) JavaScript Mode

Parameters:

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

Since:

2.13

getOutputDB

public String getOutputDB()

Gets the (optional) database name where the output collection should reside

Returns:

the name of the database the result is stored in, or null.

setOutputDB

public void setOutputDB(String outputDB)

Sets the (optional) database name where the output collection should reside

Parameters:

outputDB - the name of the database to send the Map Reduce output to

getBypassDocumentValidation

public Boolean getBypassDocumentValidation()

Gets whether to bypass document validation, or null if unspecified. The default is null.

Returns:

whether to bypass document validation, or null if unspecified.

Since:

2.14

Since server release

3.2

setBypassDocumentValidation

public void setBypassDocumentValidation(Boolean bypassDocumentValidation)

Sets whether to bypass document validation.

Parameters:

bypassDocumentValidation - whether to bypass document validation, or null if unspecified

Since:

2.14

Since server release

3.2

toDBObject

public DBObject toDBObject()

Turns this command into a DBObject representation of this map reduce command.

Returns:

a DBObject that contains the MongoDB document representation of this command.

setReadPreference

public void setReadPreference(ReadPreference preference)

Sets the read preference for this command. See the * documentation for ReadPreference for more information.

Parameters:

preference - Read Preference to use

getReadPreference

public ReadPreference getReadPreference()

Gets the read preference

Returns:

the readPreference

getCollation

public Collation getCollation()

Returns the collation

Returns:

the collation

Since:

3.4

Since server release

3.4

setCollation

public void setCollation(Collation collation)

Sets the collation options

Parameters:

collation - the collation options

Since:

3.4

Since server release

3.4

toString

public String toString()

Overrides:

toString in class Object