com.allanbank.mongodb.builder

Class GroupBy

java.lang.Object

com.allanbank.mongodb.builder.GroupBy

public class GroupBy
extends Object

Group provides a container for all of the options to a group command. A GroupBy.Builder is provided to assist in creating a GroupBy.

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 ©:

2012-2013, Allanbank Consulting, Inc., All Rights Reserved

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GroupBy.Builder Builder provides a builder for Group commands.

Field Summary

Fields

Modifier and Type	Field and Description
static Version	MAX_TIMEOUT_VERSION The first version of MongoDB to support the group command with the ability to limit the execution time on the server.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	GroupBy(GroupBy.Builder builder) Creates a new GroupBy.

Method Summary

Methods

Modifier and Type	Method and Description
static GroupBy.Builder	builder() Creates a new builder for a GroupBy.
String	getFinalizeFunction() Returns the finalizer function to run for each group.
Document	getInitialValue() Returns the initial value for each group.
String	getKeyFunction() Returns the function to return the key for a document.
Set<String>	getKeys() Returns the fields to group by.
long	getMaximumTimeMilliseconds() Returns the maximum amount of time to allow the command to run on the Server before it is aborted.
Document	getQuery() Returns the query to select the documents to run the group against.
ReadPreference	getReadPreference() Returns the ReadPreference specifying which servers may be used to execute the GroupBy command.
String	getReduceFunction() Returns the reduce function taking the previous value and the current value and returning the new reduced value.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_TIMEOUT_VERSION

public static final Version MAX_TIMEOUT_VERSION

The first version of MongoDB to support the group command with the ability to limit the execution time on the server.

Constructor Detail

GroupBy

protected GroupBy(GroupBy.Builder builder)
           throws IllegalArgumentException

Creates a new GroupBy.

Parameters:

builder - The builder to copy the state from.

Throws:

IllegalArgumentException - If neither the keys nor key function have been set.

Method Detail

builder

public static GroupBy.Builder builder()

Creates a new builder for a GroupBy.

Returns:

The builder to construct a GroupBy.

getFinalizeFunction

public String getFinalizeFunction()

Returns the finalizer function to run for each group.

Returns:

The finalizer function to run for each group.

getInitialValue

public Document getInitialValue()

Returns the initial value for each group.

Returns:

The initial value for each group.

getKeyFunction

public String getKeyFunction()

Returns the function to return the key for a document. Used instead of the getKeys() to dynamically determine the group for each document.

Returns:

The function to return the key for a document. Used instead of the getKeys() to dynamically determine the group for each document.

getKeys

public Set<String> getKeys()

Returns the fields to group by.

Returns:

The fields to group by.

getMaximumTimeMilliseconds

public long getMaximumTimeMilliseconds()

Returns the maximum amount of time to allow the command to run on the Server before it is aborted.

Returns:

The maximum amount of time to allow the command to run on the Server before it is aborted.

Since:

MongoDB 2.6

getQuery

public Document getQuery()

Returns the query to select the documents to run the group against.

Returns:

The query to select the documents to run the group against.

getReadPreference

public ReadPreference getReadPreference()

Returns the ReadPreference specifying which servers may be used to execute the GroupBy command.

If null then the MongoCollection instance's ReadPreference will be used.

Returns:

The read preference to use.

See Also:

MongoCollection.getReadPreference()

getReduceFunction

public String getReduceFunction()

Returns the reduce function taking the previous value and the current value and returning the new reduced value.

Returns:

The reduce function taking the previous value and the current value and returning the new reduced value.