MapReduce (mongodb-async-driver 1.2.2 API)

java.lang.Object
- com.allanbank.mongodb.builder.MapReduce

```
public class MapReduce
extends Object
```
Represents the state of a single MongoCollection.mapReduce(com.allanbank.mongodb.builder.MapReduce) command. Objects of this class are created using the nested MapReduce.Builder.

API Notice:

This class is part of the driver's API. Public and protected members will be deprecated for at least 1 non-bugfix release (version numbers are <major>.<minor>.<bugfix>) before being removed or modified.

Copyright ©:

2011-2013, Allanbank Consulting, Inc., All Rights Reserved

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`MapReduce.Builder` Helper for creating immutable `MapReduce` commands.
`static class`	`MapReduce.OutputType` Enumeration of the possible output types.

Constructor Summary

Constructors
Modifier Constructor and Description

protected MapReduce(MapReduce.Builder builder)
Create a new MapReduce.

Constructors
Modifier	Constructor and Description
`protected`	`MapReduce(MapReduce.Builder builder)` Create a new MapReduce.

Method Summary

Methods
Modifier and Type	Method and Description
`static MapReduce.Builder`	`builder()` Creates a new builder for a `MapReduce`.
`String`	`getFinalizeFunction()` Returns the finalize function to apply to the final results of the reduce function.
`int`	`getLimit()` Returns the limit for the number of objects to be used as input to the map/reduce.
`String`	`getMapFunction()` Returns the map functions to apply to each selected document.
`String`	`getOutputDatabase()` Returns the name of the output database if the output type is One of `MapReduce.OutputType.REPLACE`, `MapReduce.OutputType.MERGE`, or `MapReduce.OutputType.REDUCE`.
`String`	`getOutputName()` Returns the name of the output collection if the output type is One of `MapReduce.OutputType.REPLACE`, `MapReduce.OutputType.MERGE`, or `MapReduce.OutputType.REDUCE`.
`MapReduce.OutputType`	`getOutputType()` Returns the handling for the output of the map/reduce.
`Document`	`getQuery()` Returns the query to select the documents to run the map/reduce against.
`ReadPreference`	`getReadPreference()` Returns the `ReadPreference` specifying which servers may be used to execute the `MapReduce` command.
`String`	`getReduceFunction()` Returns the reduce function to apply to the emitted output of the map function.
`Document`	`getScope()` Returns the scoped values to expose to the map/reduce/finalize functions.
`Document`	`getSort()` Returns the sort to apply to the input objects.
`boolean`	`isJsMode()` Returns true to limit the translation of the documents to an from BSON/JavaScript.
`boolean`	`isKeepTemp()` Returns true to drop the temporary collections created during the map/reduce.
`boolean`	`isVerbose()` Returns true to emit progress messages in the server logs.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - MapReduce
```
protected MapReduce(MapReduce.Builder builder)
```
    Create a new MapReduce.
    
    Parameters:
    builder - The builder to copy state from.
- Method Detail
  - builder
```
public static MapReduce.Builder builder()
```
    Creates a new builder for a MapReduce.
    
    Returns:
    The builder to construct a MapReduce.
  - getFinalizeFunction
```
public String getFinalizeFunction()
```
    Returns the finalize function to apply to the final results of the reduce function.
    
    Returns:
    The finalize function to apply to the final results of the reduce function.
  - getLimit
```
public int getLimit()
```
    Returns the limit for the number of objects to be used as input to the map/reduce.
    
    Returns:
    The limit for the number of objects to be used as input to the map/reduce.
  - getMapFunction
```
public String getMapFunction()
```
    Returns the map functions to apply to each selected document.
    
    Returns:
    The map functions to apply to each selected document.
  - getOutputDatabase
```
public String getOutputDatabase()
```
    Returns the name of the output database if the output type is One of MapReduce.OutputType.REPLACE, MapReduce.OutputType.MERGE, or MapReduce.OutputType.REDUCE.
    
    Returns:
    The name of the output database if the output type is One of MapReduce.OutputType.REPLACE, MapReduce.OutputType.MERGE, or MapReduce.OutputType.REDUCE.
  - getOutputName
```
public String getOutputName()
```
    Returns the name of the output collection if the output type is One of MapReduce.OutputType.REPLACE, MapReduce.OutputType.MERGE, or MapReduce.OutputType.REDUCE.
    
    Returns:
    The name of the output collection if the output type is One of MapReduce.OutputType.REPLACE, MapReduce.OutputType.MERGE, or MapReduce.OutputType.REDUCE.
  - getOutputType
```
public MapReduce.OutputType getOutputType()
```
    Returns the handling for the output of the map/reduce.
    
    Returns:
    The handling for the output of the map/reduce.
  - getQuery
```
public Document getQuery()
```
    Returns the query to select the documents to run the map/reduce against.
    
    Returns:
    The query to select the documents to run the map/reduce against.
  - getReadPreference
```
public ReadPreference getReadPreference()
```
    Returns the ReadPreference specifying which servers may be used to execute the MapReduce command.
    If null then the MongoCollection instance's ReadPreference will be used.
    
    NOTE: Passing of read preferences to a mongos does not work in a sharded configuration. The query will always be run on the primary members of all shards.
    
    Returns:
    The read preference to use.
    See Also:
    MongoCollection.getReadPreference()
  - getReduceFunction
```
public String getReduceFunction()
```
    Returns the reduce function to apply to the emitted output of the map function.
    
    Returns:
    The reduce function to apply to the emitted output of the map function.
  - getScope
```
public Document getScope()
```
    Returns the scoped values to expose to the map/reduce/finalize functions.
    
    Returns:
    The scoped values to expose to the map/reduce/finalize functions.
  - getSort
```
public Document getSort()
```
    Returns the sort to apply to the input objects. Useful for optimization, like sorting by the emit key for fewer reduces.
    
    Returns:
    The sort to apply to the input objects. Useful for optimization, like sorting by the emit key for fewer reduces.
  - isJsMode
```
public boolean isJsMode()
```
    Returns true to limit the translation of the documents to an from BSON/JavaScript.
    
    Returns:
    True to limit the translation of the documents to an from BSON/JavaScript.
  - isKeepTemp
```
public boolean isKeepTemp()
```
    Returns true to drop the temporary collections created during the map/reduce.
    
    Returns:
    True to drop the temporary collections created during the map/reduce.
  - isVerbose
```
public boolean isVerbose()
```
    Returns true to emit progress messages in the server logs.
    
    Returns:
    True to emit progress messages in the server logs.

Class MapReduce

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

MapReduce

Method Detail

builder

getFinalizeFunction

getLimit

getMapFunction

getOutputDatabase

getOutputName

getOutputType

getQuery

getReadPreference

getReduceFunction

getScope

getSort

isJsMode

isKeepTemp

isVerbose