Accumulators

object Accumulators

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

Since: 1.0
See also: Aggregation pipeline
Accumulators
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final def !=(arg0: Any): Boolean
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final def ##: Int
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final def ==(arg0: Any): Boolean
Definition Classes
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def accumulator(fieldName: String, initFunction: String, initArgs: Seq[String], accumulateFunction: String, accumulateArgs: Seq[String], mergeFunction: String, finalizeFunction: String, lang: String): BsonField
Creates an $accumulator pipeline stage
Creates an $accumulator pipeline stage
fieldName
the field name
initFunction
a function used to initialize the state
initArgs
init function’s arguments (may be null)
accumulateFunction
a function used to accumulate documents
accumulateArgs
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
1.2
Note
Requires MongoDB 4.4 or greater
See also
$accumulator
def accumulator(fieldName: String, initFunction: String, initArgs: Seq[String], accumulateFunction: String, accumulateArgs: Seq[String], mergeFunction: String, finalizeFunction: String): BsonField
Creates an $accumulator pipeline stage
Creates an $accumulator pipeline stage
fieldName
the field name
initFunction
a function used to initialize the state
initArgs
init function’s arguments (may be null)
accumulateFunction
a function used to accumulate documents
accumulateArgs
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
1.2
Note
Requires MongoDB 4.4 or greater
See also
$accumulator
def accumulator(fieldName: String, initFunction: String, accumulateFunction: String, mergeFunction: String, finalizeFunction: String): BsonField
Creates an $accumulator pipeline stage
Creates an $accumulator pipeline stage
fieldName
the field name
initFunction
a function used to initialize the state
accumulateFunction
a function used to accumulate documents
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
1.2
Note
Requires MongoDB 4.4 or greater
See also
$accumulator
def accumulator(fieldName: String, initFunction: String, accumulateFunction: String, mergeFunction: String): BsonField
Creates an $accumulator pipeline stage
Creates an $accumulator pipeline stage
fieldName
the field name
initFunction
a function used to initialize the state
accumulateFunction
a function used to accumulate documents
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.
returns
the $accumulator pipeline stage
Since
1.2
Note
Requires MongoDB 4.4 or greater
See also
$accumulator
def addToSet[TExpression](fieldName: String, expression: TExpression): BsonField
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.
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.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
See also
$addToSet
final def asInstanceOf[T0]: T0
Definition Classes
Any
def avg[TExpression](fieldName: String, expression: TExpression): BsonField
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.
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.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
See also
$avg
def bottom[OutExpression](fieldName: String, sortBy: Bson, outExpression: OutExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a value of the given outExpression computed for the bottom element within a group sorted according to the provided sort specification.
Returns a combination of a computed field and an accumulator that produces a value of the given outExpression computed for the bottom element within a group sorted according to the provided sort specification.
OutExpression
The type of the output expression.
fieldName
The field computed by the accumulator.
sortBy
The sort specification. The syntax is identical to the one expected by Aggregates.sort.
outExpression
The output expression.
returns
The requested BsonField.
Since
4.7
Note
Requires MongoDB 5.2 or greater
See also
$bottom
def bottomN[OutExpression, NExpression](fieldName: String, sortBy: Bson, outExpression: OutExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON Array of values of the given outExpression computed for the bottom N elements within a group sorted according to the provided sort specification, where N is the positive integral value of the nExpression.
Returns a combination of a computed field and an accumulator that produces a BSON Array of values of the given outExpression computed for the bottom N elements within a group sorted according to the provided sort specification, where N is the positive integral value of the nExpression.
OutExpression
The type of the output expression.
NExpression
The type of the limiting expression.
fieldName
The field computed by the accumulator.
sortBy
The sort specification. The syntax is identical to the one expected by Aggregates.sort.
outExpression
The output expression.
nExpression
The expression limiting the number of produced values.
returns
The requested BsonField.
Since
4.7
Note
Requires MongoDB 5.2 or greater
See also
$bottomN
def clone(): AnyRef
Attributes
protected[lang]
Definition Classes
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@throws(classOf[java.lang.CloneNotSupportedException]) @native() @IntrinsicCandidate()
final def eq(arg0: AnyRef): Boolean
Definition Classes
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def equals(arg0: AnyRef): Boolean
Definition Classes
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def first[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a $group operation representing the value of the given expression when applied to the first member of the group.
Gets a field name for a $group operation representing the value of the given expression when applied to the first member of the group.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
See also
$first
def firstN[InExpression, NExpression](fieldName: String, inExpression: InExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON Array of values of the given inExpression computed for the first N elements within a presorted group, where N is the positive integral value of the nExpression.
Returns a combination of a computed field and an accumulator that produces a BSON Array of values of the given inExpression computed for the first N elements within a presorted group, where N is the positive integral value of the nExpression.
InExpression
The type of the input expression.
NExpression
The type of the limiting expression.
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
Note
Requires MongoDB 5.2 or greater
See also
$firstN
final def getClass(): Class[_ <: AnyRef]
Definition Classes
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Annotations
@native() @IntrinsicCandidate()
def hashCode(): Int
Definition Classes
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Annotations
@native() @IntrinsicCandidate()
final def isInstanceOf[T0]: Boolean
Definition Classes
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def last[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a $group operation representing the value of the given expression when applied to the last member of the group.
Gets a field name for a $group operation representing the value of the given expression when applied to the last member of the group.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
See also
$last
def lastN[InExpression, NExpression](fieldName: String, inExpression: InExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON Array of values of the given inExpression computed for the last N elements within a presorted group where N is the positive integral value of the nExpression.
Returns a combination of a computed field and an accumulator that produces a BSON Array of values of the given inExpression computed for the last N elements within a presorted group where N is the positive integral value of the nExpression.
InExpression
The type of the input expression.
NExpression
The type of the limiting expression.
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
Note
Requires MongoDB 5.2 or greater
See also
$lastN
def max[TExpression](fieldName: String, expression: TExpression): BsonField
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.
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.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
See also
$max
def maxN[InExpression, NExpression](fieldName: String, inExpression: InExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON Array of N largest values of the given inExpression, where N is the positive integral value of the nExpression.
Returns a combination of a computed field and an accumulator that produces a BSON Array of N largest values of the given inExpression, where N is the positive integral value of the nExpression.
InExpression
The type of the input expression.
NExpression
The type of the limiting expression.
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
Note
Requires MongoDB 5.2 or greater
See also
$maxN
def mergeObjects[TExpression](fieldName: String, expression: TExpression): BsonField
Gets a field name for a $group operation representing the result of merging the fields of the documents.
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.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
Since
4.4
See also
$mergeObjects
def min[TExpression](fieldName: String, expression: TExpression): BsonField
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.
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.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
See also
$min
def minN[InExpression, NExpression](fieldName: String, inExpression: InExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON Array of N smallest values of the given inExpression, where N is the positive integral value of the nExpression.
Returns a combination of a computed field and an accumulator that produces a BSON Array of N smallest values of the given inExpression, where N is the positive integral value of the nExpression.
InExpression
The type of the input expression.
NExpression
The type of the limiting expression.
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
Note
Requires MongoDB 5.2 or greater
See also
$minN
final def ne(arg0: AnyRef): Boolean
Definition Classes
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final def notify(): Unit
Definition Classes
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Annotations
@native() @IntrinsicCandidate()
final def notifyAll(): Unit
Definition Classes
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Annotations
@native() @IntrinsicCandidate()
def push[TExpression](fieldName: String, expression: TExpression): BsonField
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.
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.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
See also
$push
def stdDevPop[TExpression](fieldName: String, expression: TExpression): BsonField
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.
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.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
Since
1.1
Note
Requires MongoDB 3.2 or greater
See also
$stdDevPop
def stdDevSamp[TExpression](fieldName: String, expression: TExpression): BsonField
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.
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.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
Since
1.1
Note
Requires MongoDB 3.2 or greater
See also
$stdDevSamp
def sum[TExpression](fieldName: String, expression: TExpression): BsonField
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.
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.
TExpression
the expression type
fieldName
the field name
expression
the expression
returns
the field
See also
$sum
final def synchronized[T0](arg0: => T0): T0
Definition Classes
AnyRef
def toString(): String
Definition Classes
AnyRef → Any
def top[OutExpression](fieldName: String, sortBy: Bson, outExpression: OutExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a value of the given outExpression computed for the top element within a group sorted according to the provided sort specification.
Returns a combination of a computed field and an accumulator that produces a value of the given outExpression computed for the top element within a group sorted according to the provided sort specification.
OutExpression
The type of the output expression.
fieldName
The field computed by the accumulator.
sortBy
The sort specification. The syntax is identical to the one expected by Aggregates.sort.
outExpression
The output expression.
returns
The requested BsonField.
Since
4.7
Note
Requires MongoDB 5.2 or greater
See also
$topN
def topN[OutExpression, NExpression](fieldName: String, sortBy: Bson, outExpression: OutExpression, nExpression: NExpression): BsonField
Returns a combination of a computed field and an accumulator that produces a BSON Array of values of the given outExpression computed for the top N elements within a group sorted according to the provided sort specification, where N is the positive integral value of the nExpression.
Returns a combination of a computed field and an accumulator that produces a BSON Array of values of the given outExpression computed for the top N elements within a group sorted according to the provided sort specification, where N is the positive integral value of the nExpression.
OutExpression
The type of the output expression.
NExpression
The type of the limiting expression.
fieldName
The field computed by the accumulator.
sortBy
The sort specification. The syntax is identical to the one expected by Aggregates.sort.
outExpression
The output expression.
nExpression
The expression limiting the number of produced values.
returns
The requested BsonField.
Since
4.7
Note
Requires MongoDB 5.2 or greater
See also
$topN
final def wait(arg0: Long, arg1: Int): Unit
Definition Classes
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@throws(classOf[java.lang.InterruptedException])
final def wait(arg0: Long): Unit
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@throws(classOf[java.lang.InterruptedException]) @native()
final def wait(): Unit
Definition Classes
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@throws(classOf[java.lang.InterruptedException])

Deprecated Value Members

def finalize(): Unit
Attributes
protected[lang]
Definition Classes
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@throws(classOf[java.lang.Throwable]) @Deprecated
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object Accumulators

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Accumulators

object Accumulators

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Accumulators