Package com.mongodb.client.model
Class Accumulators
java.lang.Object
com.mongodb.client.model.Accumulators
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 TypeMethodDescriptionstatic BsonField
accumulator
(String fieldName, String initFunction, String accumulateFunction, String mergeFunction) Creates an $accumulator pipeline stagestatic BsonField
accumulator
(String fieldName, String initFunction, String accumulateFunction, String mergeFunction, String finalizeFunction) Creates an $accumulator pipeline stagestatic BsonField
accumulator
(String fieldName, String initFunction, String accumulateFunction, String mergeFunction, String finalizeFunction, String lang) Creates an $accumulator pipeline stagestatic BsonField
accumulator
(String fieldName, String initFunction, List<String> initArgs, String accumulateFunction, List<String> accumulateArgs, String mergeFunction, String finalizeFunction) Creates an $accumulator pipeline stagestatic BsonField
accumulator
(String fieldName, String initFunction, List<String> initArgs, String accumulateFunction, List<String> accumulateArgs, String mergeFunction, String finalizeFunction, String lang) Creates an $accumulator pipeline stagestatic <TExpression>
BsonFieldGets 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>
BsonFieldGets 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 <OutExpression>
BsonFieldReturns a combination of a computed field and an accumulator that produces a value of the givenoutExpression
computed for the bottom element within a group sorted according to the providedsortBy
specification.static <OutExpression,
NExpression>
BsonFieldReturns a combination of a computed field and an accumulator that produces a BSONArray
of values of the givenoutExpression
computed for the bottomN
elements within a group sorted according to the providedsortBy
specification, whereN
is the positive integral value of thenExpression
.static <TExpression>
BsonFieldGets a field name for a $group operation representing the value of the given expression when applied to the first member of the group.static <InExpression,
NExpression>
BsonFieldReturns a combination of a computed field and an accumulator that produces a BSONArray
of values of the giveninExpression
computed for the firstN
elements within a presorted group, whereN
is the positive integral value of thenExpression
.static <TExpression>
BsonFieldGets a field name for a $group operation representing the value of the given expression when applied to the last member of the group.static <InExpression,
NExpression>
BsonFieldReturns a combination of a computed field and an accumulator that produces a BSONArray
of values of the giveninExpression
computed for the lastN
elements within a presorted group, whereN
is the positive integral value of thenExpression
.static <TExpression>
BsonFieldGets 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 <InExpression,
NExpression>
BsonFieldReturns a combination of a computed field and an accumulator that produces a BSONArray
ofN
largest values of the giveninExpression
, whereN
is the positive integral value of thenExpression
.static <TExpression>
BsonFieldmergeObjects
(String fieldName, TExpression expression) Gets a field name for a $group operation representing the result of merging the fields of the documents.static <TExpression>
BsonFieldGets 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 <InExpression,
NExpression>
BsonFieldReturns a combination of a computed field and an accumulator that produces a BSONArray
ofN
smallest values of the giveninExpression
, whereN
is the positive integral value of thenExpression
.static <TExpression>
BsonFieldGets 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>
BsonFieldGets 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>
BsonFieldstdDevSamp
(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>
BsonFieldGets 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.static <OutExpression>
BsonFieldReturns a combination of a computed field and an accumulator that produces a value of the givenoutExpression
computed for the top element within a group sorted according to the providedsortBy
specification.static <OutExpression,
NExpression>
BsonFieldReturns a combination of a computed field and an accumulator that produces a BSONArray
of values of the givenoutExpression
computed for the topN
elements within a group sorted according to the providedsortBy
specification, whereN
is the positive integral value of thenExpression
.
-
Method Details
-
sum
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 nameexpression
- the expression- Returns:
- the field
- MongoDB documentation
- $sum
-
avg
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 nameexpression
- the expression- Returns:
- the field
- MongoDB documentation
- $avg
-
first
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 nameexpression
- the expression- Returns:
- the field
- MongoDB documentation
- $first
-
firstN
public static <InExpression,NExpression> BsonField firstN(String fieldName, InExpression inExpression, NExpression nExpression) Returns a combination of a computed field and an accumulator that produces a BSONArray
of values of the giveninExpression
computed for the firstN
elements within a presorted group, whereN
is the positive integral value of thenExpression
.- Type Parameters:
InExpression
- The type of the input expression.NExpression
- The type of the limiting expression.- Parameters:
fieldName
- The field computed by the accumulator.inExpression
- The input expression.nExpression
- The expression limiting the number of produced values.- Returns:
- The requested
BsonField
. - Since:
- 4.7
-
top
public static <OutExpression> BsonField top(String fieldName, Bson sortBy, OutExpression outExpression) Returns a combination of a computed field and an accumulator that produces a value of the givenoutExpression
computed for the top element within a group sorted according to the providedsortBy
specification.- Type Parameters:
OutExpression
- The type of the output expression.- Parameters:
fieldName
- The field computed by the accumulator.sortBy
- The sort specification. The syntax is identical to the one expected byAggregates.sort(Bson)
.outExpression
- The output expression.- Returns:
- The requested
BsonField
. - Since:
- 4.7
-
topN
public static <OutExpression,NExpression> BsonField topN(String fieldName, Bson sortBy, OutExpression outExpression, NExpression nExpression) Returns a combination of a computed field and an accumulator that produces a BSONArray
of values of the givenoutExpression
computed for the topN
elements within a group sorted according to the providedsortBy
specification, whereN
is the positive integral value of thenExpression
.- Type Parameters:
OutExpression
- The type of the output expression.NExpression
- The type of the limiting expression.- Parameters:
fieldName
- The field computed by the accumulator.sortBy
- The sort specification. The syntax is identical to the one expected byAggregates.sort(Bson)
.outExpression
- The output expression.nExpression
- The expression limiting the number of produced values.- Returns:
- The requested
BsonField
. - Since:
- 4.7
-
last
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 nameexpression
- the expression- Returns:
- the field
- MongoDB documentation
- $last
-
lastN
public static <InExpression,NExpression> BsonField lastN(String fieldName, InExpression inExpression, NExpression nExpression) Returns a combination of a computed field and an accumulator that produces a BSONArray
of values of the giveninExpression
computed for the lastN
elements within a presorted group, whereN
is the positive integral value of thenExpression
.- Type Parameters:
InExpression
- The type of the input expression.NExpression
- The type of the limiting expression.- Parameters:
fieldName
- The field computed by the accumulator.inExpression
- The input expression.nExpression
- The expression limiting the number of produced values.- Returns:
- The requested
BsonField
. - Since:
- 4.7
-
bottom
public static <OutExpression> BsonField bottom(String fieldName, Bson sortBy, OutExpression outExpression) Returns a combination of a computed field and an accumulator that produces a value of the givenoutExpression
computed for the bottom element within a group sorted according to the providedsortBy
specification.- Type Parameters:
OutExpression
- The type of the output expression.- Parameters:
fieldName
- The field computed by the accumulator.sortBy
- The sort specification. The syntax is identical to the one expected byAggregates.sort(Bson)
.outExpression
- The output expression.- Returns:
- The requested
BsonField
. - Since:
- 4.7
-
bottomN
public static <OutExpression,NExpression> BsonField bottomN(String fieldName, Bson sortBy, OutExpression outExpression, NExpression nExpression) Returns a combination of a computed field and an accumulator that produces a BSONArray
of values of the givenoutExpression
computed for the bottomN
elements within a group sorted according to the providedsortBy
specification, whereN
is the positive integral value of thenExpression
.- Type Parameters:
OutExpression
- The type of the output expression.NExpression
- The type of the limiting expression.- Parameters:
fieldName
- The field computed by the accumulator.sortBy
- The sort specification. The syntax is identical to the one expected byAggregates.sort(Bson)
.outExpression
- The output expression.nExpression
- The expression limiting the number of produced values.- Returns:
- The requested
BsonField
. - Since:
- 4.7
-
max
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 nameexpression
- the expression- Returns:
- the field
- MongoDB documentation
- $max
-
maxN
public static <InExpression,NExpression> BsonField maxN(String fieldName, InExpression inExpression, NExpression nExpression) Returns a combination of a computed field and an accumulator that produces a BSONArray
ofN
largest values of the giveninExpression
, whereN
is the positive integral value of thenExpression
.- Type Parameters:
InExpression
- The type of the input expression.NExpression
- The type of the limiting expression.- Parameters:
fieldName
- The field computed by the accumulator.inExpression
- The input expression.nExpression
- The expression limiting the number of produced values.- Returns:
- The requested
BsonField
. - Since:
- 4.7
-
min
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 nameexpression
- the expression- Returns:
- the field
- MongoDB documentation
- $min
-
minN
public static <InExpression,NExpression> BsonField minN(String fieldName, InExpression inExpression, NExpression nExpression) Returns a combination of a computed field and an accumulator that produces a BSONArray
ofN
smallest values of the giveninExpression
, whereN
is the positive integral value of thenExpression
.- Type Parameters:
InExpression
- The type of the input expression.NExpression
- The type of the limiting expression.- Parameters:
fieldName
- The field computed by the accumulator.inExpression
- The input expression.nExpression
- The expression limiting the number of produced values.- Returns:
- The requested
BsonField
. - Since:
- 4.7
-
push
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 nameexpression
- the expression- Returns:
- the field
- MongoDB documentation
- $push
-
addToSet
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 nameexpression
- the expression- Returns:
- the field
- MongoDB documentation
- $addToSet
-
mergeObjects
Gets a field name for a $group operation representing the result of merging the fields of the documents. If documents to merge include the same field name, the field, in the resulting document, has the value from the last document merged for the field.- Type Parameters:
TExpression
- the expression type- Parameters:
fieldName
- the field nameexpression
- the expression- Returns:
- the field
- Since:
- 4.4
- MongoDB documentation
- $mergeObjects
-
stdDevPop
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 nameexpression
- the expression- Returns:
- the field
- Since:
- 3.2
- MongoDB documentation
- $stdDevPop
- Since server release
- 3.2
-
stdDevSamp
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 nameexpression
- the expression- Returns:
- the field
- Since:
- 3.2
- MongoDB documentation
- $stdDevSamp
- Since server release
- 3.2
-
accumulator
public static BsonField accumulator(String fieldName, String initFunction, String accumulateFunction, String mergeFunction) Creates an $accumulator pipeline stage- Parameters:
fieldName
- the field nameinitFunction
- a function used to initialize the stateaccumulateFunction
- a function used to accumulate documentsmergeFunction
- a function used to merge two internal states, e.g. accumulated on different shards or threads. It returns the resulting state of the accumulator.- Returns:
- the $accumulator pipeline stage
- Since:
- 4.1
- MongoDB documentation
- $accumulator
- Since server release
- 4.4
-
accumulator
public static BsonField accumulator(String fieldName, String initFunction, String accumulateFunction, String mergeFunction, @Nullable String finalizeFunction) Creates an $accumulator pipeline stage- Parameters:
fieldName
- the field nameinitFunction
- a function used to initialize the stateaccumulateFunction
- a function used to accumulate documentsmergeFunction
- a function used to merge two internal states, e.g. accumulated on different shards or threads. It returns the resulting state of the accumulator.finalizeFunction
- a function used to finalize the state and return the result (may be null)- Returns:
- the $accumulator pipeline stage
- Since:
- 4.1
- MongoDB documentation
- $accumulator
- Since server release
- 4.4
-
accumulator
public static BsonField accumulator(String fieldName, String initFunction, @Nullable List<String> initArgs, String accumulateFunction, @Nullable List<String> accumulateArgs, String mergeFunction, @Nullable String finalizeFunction) Creates an $accumulator pipeline stage- Parameters:
fieldName
- the field nameinitFunction
- a function used to initialize the stateinitArgs
- init function’s arguments (may be null)accumulateFunction
- a function used to accumulate documentsaccumulateArgs
- additional accumulate function’s arguments (may be null). The first argument to the function is ‘state’.mergeFunction
- a function used to merge two internal states, e.g. accumulated on different shards or threads. It returns the resulting state of the accumulator.finalizeFunction
- a function used to finalize the state and return the result (may be null)- Returns:
- the $accumulator pipeline stage
- Since:
- 4.1
- MongoDB documentation
- $accumulator
- Since server release
- 4.4
-
accumulator
public static BsonField accumulator(String fieldName, String initFunction, String accumulateFunction, String mergeFunction, @Nullable String finalizeFunction, String lang) Creates an $accumulator pipeline stage- Parameters:
fieldName
- the field nameinitFunction
- a function used to initialize the stateaccumulateFunction
- a function used to accumulate documentsmergeFunction
- a function used to merge two internal states, e.g. accumulated on different shards or threads. It returns the resulting state of the accumulator.finalizeFunction
- a function used to finalize the state and return the result (may be null)lang
- a language specifier- Returns:
- the $accumulator pipeline stage
- Since:
- 4.1
- MongoDB documentation
- $accumulator
- Since server release
- 4.4
-
accumulator
public static BsonField accumulator(String fieldName, String initFunction, @Nullable List<String> initArgs, String accumulateFunction, @Nullable List<String> accumulateArgs, String mergeFunction, @Nullable String finalizeFunction, String lang) Creates an $accumulator pipeline stage- Parameters:
fieldName
- the field nameinitFunction
- a function used to initialize the stateinitArgs
- init function’s arguments (may be null)accumulateFunction
- a function used to accumulate documentsaccumulateArgs
- additional accumulate function’s arguments (may be null). The first argument to the function is ‘state’.mergeFunction
- a function used to merge two internal states, e.g. accumulated on different shards or threads. It returns the resulting state of the accumulator.finalizeFunction
- a function used to finalize the state and return the result (may be null)lang
- a language specifier- Returns:
- the $accumulator pipeline stage
- Since:
- 4.1
- MongoDB documentation
- $accumulator
- Since server release
- 4.4
-