Package com.mongodb

Class MapReduceOutput

java.lang.Object

com.mongodb.MapReduceOutput

public class MapReduceOutput
extends Object

Represents the result of a map/reduce operation. Users should interact with the results of the map reduce via the results() method, or by interacting directly with the collection the results were input into.

MongoDB documentation

Map-Reduce

Method Summary

Modifier and Type	Method	Description
void	drop()	Drops the collection that holds the results.
String	getCollectionName()	Get the name of the collection that the results of the map reduce were saved into.
DBObject	getCommand()	Get the original command that was sent to the database.
String	getDatabaseName()	Get the name of the database that the results of the map reduce were saved into.
int	getDuration()	Get the amount of time, in milliseconds, that it took to run this map reduce.
int	getEmitCount()	Get the number of messages emitted from the provided map function.
int	getInputCount()	Get the number of documents that were input into the map reduce operation
DBCollection	getOutputCollection()	Gets the collection that holds the results (Will return null if results are Inline).
int	getOutputCount()	Get the number of documents generated as a result of this map reduce
Iterable<DBObject>	results()	Returns an iterable containing the results of the operation.
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

results

public Iterable<DBObject> results()

Returns an iterable containing the results of the operation.

Returns:

the results in iterable form

drop

public void drop()

Drops the collection that holds the results. Does nothing if the map-reduce returned the results inline.

getOutputCollection

public DBCollection getOutputCollection()

Gets the collection that holds the results (Will return null if results are Inline).

Returns:

the collection or null

getCommand

public DBObject getCommand()

Get the original command that was sent to the database.

Returns:

a DBObject containing the values of the original map-reduce command.

toString

public String toString()

Overrides:

toString in class Object

getCollectionName

@Nullable
public final String getCollectionName()

Get the name of the collection that the results of the map reduce were saved into. If the map reduce was an inline operation (i.e . the results were returned directly from calling the map reduce) this will return null.

Returns:

the name of the collection that the map reduce results are stored in

getDatabaseName

public String getDatabaseName()

Get the name of the database that the results of the map reduce were saved into. If the map reduce was an inline operation (i.e . the results were returned directly from calling the map reduce) this will return null.

Returns:

the name of the database that holds the collection that the map reduce results are stored in

getDuration

public int getDuration()

Get the amount of time, in milliseconds, that it took to run this map reduce.

Returns:

an int representing the number of milliseconds it took to run the map reduce operation

getInputCount

public int getInputCount()

Get the number of documents that were input into the map reduce operation

Returns:

the number of documents that read while processing this map reduce

getOutputCount

public int getOutputCount()

Get the number of documents generated as a result of this map reduce

Returns:

the number of documents output by the map reduce

getEmitCount

public int getEmitCount()

Get the number of messages emitted from the provided map function.

Returns:

the number of items emitted from the map function