com.mongodb.client.model

Enum MapReduceAction

java.lang.Object

java.lang.Enum<MapReduceAction>

com.mongodb.client.model.MapReduceAction

All Implemented Interfaces:

Serializable, Comparable<MapReduceAction>

public enum MapReduceAction
extends Enum<MapReduceAction>

The map reduce to collection actions.

These actions are only available when passing out a collection that already exists. This option is not available on secondary members of replica sets. The Enum values dictate what to do with the output collection if it already exists when the map reduce is run.

Since:

3.0

MongoDB documentation

mapReduce Command

mapReduce Overview

Enum Constant Summary

Enum Constants

Enum Constant and Description
MERGE Merge the new result with the existing result if the output collection already exists.
REDUCE Merge the new result with the existing result if the output collection already exists.
REPLACE Replace the contents of the collectionName if the collection with the collectionName exists.

Method Summary

Modifier and Type	Method and Description
String	getValue()
static MapReduceAction	valueOf(String name) Returns the enum constant of this type with the specified name.
static MapReduceAction[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

REPLACE

public static final MapReduceAction REPLACE

Replace the contents of the collectionName if the collection with the collectionName exists.

MERGE

public static final MapReduceAction MERGE

Merge the new result with the existing result if the output collection already exists. If an existing document has the same key as the new result, overwrite that existing document.

REDUCE

public static final MapReduceAction REDUCE

Merge the new result with the existing result if the output collection already exists. If an existing document has the same key as the new result, apply the reduce function to both the new and the existing documents and overwrite the existing document with the result.

Method Detail

values

public static MapReduceAction[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (MapReduceAction c : MapReduceAction.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static MapReduceAction valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

getValue

public String getValue()

Returns:

the String representation of this Action that the MongoDB server understands