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 Doc Links

• mapreduce

Nested Class Summary

static class

MapReduceCommand.OutputType INLINE - Return results inline, no result is written to the DB server REPLACE - Save the job output to a collection, replacing its previous content MERGE - Merge the job output with the existing contents of outputTarget collection REDUCE - Reduce the job output with the existing contents of outputTarget collection

Constructor Summary

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

void	addExtraOption(String name, Object value)
DBObject	getExtraOptions()
String	getFinalize() Gets the Finalize JS Function
String	getInput() Get the name of the collection the MapReduce will read from
int	getLimit() Gets the (optional) limit on input
String	getMap() Get the map function, as a JS String
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	setFinalize(String finalize) Sets the Finalize JS Function
void	setLimit(int limit) Sets the (optional) limit on input
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()
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)
                 throws MongoException

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

Parameters:

inputCollection - the collection to read from

map - map function in javascript code

reduce - reduce function in javascript code

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

type - the type of output

query - the query to use on input

Throws:

MongoException

MongoDB Doc Links

• mapreduce

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 outputTarget

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

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

setOutputDB

public void setOutputDB(String outputDB)

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

Parameters:

outputDB -

toDBObject

public DBObject toDBObject()

addExtraOption

public void addExtraOption(String name,
                           Object value)

getExtraOptions

public DBObject getExtraOptions()

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:

toString

public String toString()

Overrides:

toString in class Object