com.mongodb.client.model

Class Accumulators

java.lang.Object

com.mongodb.client.model.Accumulators

public final class Accumulators
extends Object

Builders for accumulators used in the group pipeline stage of an aggregation pipeline.

Since:

3.1

MongoDB documentation

Aggregation pipeline

Accumulators

Expressions

Since server release

2.2

Method Summary

Modifier and Type	Method and Description
static <TExpression> BsonField	addToSet(String fieldName, TExpression expression) Gets a field name for a $group operation representing all unique values that results from applying the given expression to each document in a group of documents that share the same group by key.
static <TExpression> BsonField	avg(String fieldName, TExpression expression) Gets a field name for a $group operation representing the average of the values of the given expression when applied to all members of the group.
static <TExpression> BsonField	first(String fieldName, TExpression expression) Gets a field name for a $group operation representing the value of the given expression when applied to the first member of the group.
static <TExpression> BsonField	last(String fieldName, TExpression expression) Gets a field name for a $group operation representing the value of the given expression when applied to the last member of the group.
static <TExpression> BsonField	max(String fieldName, TExpression expression) Gets a field name for a $group operation representing the maximum of the values of the given expression when applied to all members of the group.
static <TExpression> BsonField	min(String fieldName, TExpression expression) Gets a field name for a $group operation representing the minimum of the values of the given expression when applied to all members of the group.
static <TExpression> BsonField	push(String fieldName, TExpression expression) Gets a field name for a $group operation representing an array of all values that results from applying an expression to each document in a group of documents that share the same group by key.
static <TExpression> BsonField	stdDevPop(String fieldName, TExpression expression) Gets a field name for a $group operation representing the sample standard deviation of the values of the given expression when applied to all members of the group.
static <TExpression> BsonField	stdDevSamp(String fieldName, TExpression expression) Gets a field name for a $group operation representing the sample standard deviation of the values of the given expression when applied to all members of the group.
static <TExpression> BsonField	sum(String fieldName, TExpression expression) Gets a field name for a $group operation representing the sum of the values of the given expression when applied to all members of the group.

Methods inherited from class java.lang.Object

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

Method Detail

sum

public static <TExpression> BsonField sum(String fieldName,
                                          TExpression expression)

Gets a field name for a $group operation representing the sum of the values of the given expression when applied to all members of the group.

Type Parameters:

TExpression - the expression type

Parameters:

fieldName - the field name

expression - the expression

Returns:

the field

MongoDB documentation

$sum

avg

public static <TExpression> BsonField avg(String fieldName,
                                          TExpression expression)

Gets a field name for a $group operation representing the average of the values of the given expression when applied to all members of the group.

Type Parameters:

TExpression - the expression type

Parameters:

fieldName - the field name

expression - the expression

Returns:

the field

MongoDB documentation

$avg

first

public static <TExpression> BsonField first(String fieldName,
                                            TExpression expression)

Gets a field name for a $group operation representing the value of the given expression when applied to the first member of the group.

Type Parameters:

TExpression - the expression type

Parameters:

fieldName - the field name

expression - the expression

Returns:

the field

MongoDB documentation

$first

last

public static <TExpression> BsonField last(String fieldName,
                                           TExpression expression)

Gets a field name for a $group operation representing the value of the given expression when applied to the last member of the group.

Type Parameters:

TExpression - the expression type

Parameters:

fieldName - the field name

expression - the expression

Returns:

the field

MongoDB documentation

$last

max

public static <TExpression> BsonField max(String fieldName,
                                          TExpression expression)

Gets a field name for a $group operation representing the maximum of the values of the given expression when applied to all members of the group.

Type Parameters:

TExpression - the expression type

Parameters:

fieldName - the field name

expression - the expression

Returns:

the field

MongoDB documentation

$max

min

public static <TExpression> BsonField min(String fieldName,
                                          TExpression expression)

Gets a field name for a $group operation representing the minimum of the values of the given expression when applied to all members of the group.

Type Parameters:

TExpression - the expression type

Parameters:

fieldName - the field name

expression - the expression

Returns:

the field

MongoDB documentation

$min

push

public static <TExpression> BsonField push(String fieldName,
                                           TExpression expression)

Gets a field name for a $group operation representing an array of all values that results from applying an expression to each document in a group of documents that share the same group by key.

Type Parameters:

TExpression - the expression type

Parameters:

fieldName - the field name

expression - the expression

Returns:

the field

MongoDB documentation

$push

addToSet

public static <TExpression> BsonField addToSet(String fieldName,
                                               TExpression expression)

Gets a field name for a $group operation representing all unique values that results from applying the given expression to each document in a group of documents that share the same group by key.

Type Parameters:

TExpression - the expression type

Parameters:

fieldName - the field name

expression - the expression

Returns:

the field

MongoDB documentation

$addToSet

stdDevPop

public static <TExpression> BsonField stdDevPop(String fieldName,
                                                TExpression expression)

Gets a field name for a $group operation representing the sample standard deviation of the values of the given expression when applied to all members of the group.

Use if the values encompass the entire population of data you want to represent and do not wish to generalize about a larger population.

Type Parameters:

TExpression - the expression type

Parameters:

fieldName - the field name

expression - the expression

Returns:

the field

Since:

3.2

MongoDB documentation

$stdDevPop

Since server release

3.2

stdDevSamp

public static <TExpression> BsonField stdDevSamp(String fieldName,
                                                 TExpression expression)

Gets a field name for a $group operation representing the sample standard deviation of the values of the given expression when applied to all members of the group.

Use if the values encompass a sample of a population of data from which to generalize about the population.

Type Parameters:

TExpression - the expression type

Parameters:

fieldName - the field name

expression - the expression

Returns:

the field

Since:

3.2

MongoDB documentation

$stdDevSamp

Since server release

3.2