Mongo pipelines are arrays of aggregation stages

With the MongoCollection::aggregate method, pipeline stages appear in a array. Documents pass through the stages in sequence.

db.collection.aggregate( [ { <stage> }, ... ] )

The MongoPipeline fluent interface can be used to bluid a pipeline:

var pipeline = (new MongoPipeline).
    match((new MongoMatch).eq("game", "nit")).
    group((new MongoGroup("$game._id")).sum("nitcoins", "$game.nitcoins")).
    sort((new MongoMatch).eq("nitcoins", -1)).
    limit(10)

The pipeline can then be used in an aggregation query:

collection.aggregate(pipeline)

For more information read about MongoDB pipeline operators from the MongoDB official documentation: https://docs.mongodb.com/manual/reference/operator/aggregation/

Introduced properties

fun add_stage(stage: String, json: Serializable): MongoPipeline

mongodb :: MongoPipeline :: add_stage

Add a stage to the pipeline
fun group(group: MongoGroup): MongoPipeline

mongodb :: MongoPipeline :: group

Apply group
fun limit(number: nullable Int): MongoPipeline

mongodb :: MongoPipeline :: limit

Apply limit
fun match(query: MongoMatch): MongoPipeline

mongodb :: MongoPipeline :: match

Apply match
fun project(projection: JsonObject): MongoPipeline

mongodb :: MongoPipeline :: project

Apply projection
fun skip(number: nullable Int): MongoPipeline

mongodb :: MongoPipeline :: skip

Apply skip
fun sort(projection: JsonObject): MongoPipeline

mongodb :: MongoPipeline :: sort

Apply sort
fun unwind(path: String): MongoPipeline

mongodb :: MongoPipeline :: unwind

Apply unwind

Redefined properties

redef type SELF: MongoPipeline

mongodb $ MongoPipeline :: SELF

Type of this instance, automatically specialized in every class

All properties

fun !=(other: nullable Object): Bool

core :: Object :: !=

Have self and other different values?
fun *(repeat: Int): Array[E]

core :: Array :: *

Repetition of arrays.
fun +(other: Array[E]): Array[E]

core :: Array :: +

Concatenation of arrays.
fun ==(other: nullable Object): Bool

core :: Object :: ==

Have self and other the same value?
type CLASS: Class[SELF]

core :: Object :: CLASS

The type of the class of self.
type CONCURRENT: ConcurrentCollection[E]

core :: Collection :: CONCURRENT

Type of the concurrent variant of this collection
type SELF: Object

core :: Object :: SELF

Type of this instance, automatically specialized in every class
abstract fun [](index: Int): E

core :: SequenceRead :: []

Return the index-th element of the sequence.
abstract fun []=(index: Int, item: E)

core :: Sequence :: []=

Set the item at index.
protected fun accept_json_serializer(v: JsonSerializer)

serialization :: Serializable :: accept_json_serializer

Refinable service to customize the serialization of this class to JSON
protected fun accept_msgpack_attribute_counter(v: AttributeCounter)

serialization :: Serializable :: accept_msgpack_attribute_counter

Hook to customize the behavior of the AttributeCounter
protected fun accept_msgpack_serializer(v: MsgPackSerializer)

serialization :: Serializable :: accept_msgpack_serializer

Hook to customize the serialization of this class to MessagePack
abstract fun add(item: E)

core :: SimpleCollection :: add

Add item to this collection.
fun add_all(coll: Collection[E])

core :: SimpleCollection :: add_all

Add each item of coll.
fun add_stage(stage: String, json: Serializable): MongoPipeline

mongodb :: MongoPipeline :: add_stage

Add a stage to the pipeline
protected fun add_to_bundle(bundle: NativeBundle, key: JavaString)

serialization :: Serializable :: add_to_bundle

Called by []= to dynamically choose the appropriate method according
fun append(coll: Collection[E])

core :: Sequence :: append

Add each item of coll after the last.
fun as_fifo: Queue[E]

core :: Sequence :: as_fifo

Return a FIFO proxy queue where result.take is shift.
fun as_lifo: Queue[E]

core :: Sequence :: as_lifo

Return a LIFO proxy queue (stack) where result.take is pop.
fun as_random: Queue[E]

core :: SimpleCollection :: as_random

Return a random proxy queue where result.take is random.
protected fun class_factory(name: String): CLASS

core :: Object :: class_factory

Implementation used by get_class to create the specific class.
fun class_name: String

core :: Object :: class_name

The class name of the object.
abstract fun clear

core :: RemovableCollection :: clear

Remove all items
abstract fun clone: SELF

core :: Cloneable :: clone

Duplicate self
fun combinations(r: Int): Collection[SequenceRead[E]]

core :: Collection :: combinations

All r-length combinations on self (in same order) without repeated elements.
fun combinations_with_replacement(r: Int): Collection[SequenceRead[E]]

core :: Collection :: combinations_with_replacement

All r-length combination on self (in same order) with repeated elements.
fun copy_to(start: Int, len: Int, dest: AbstractArray[E], new_start: Int)

core :: AbstractArrayRead :: copy_to

Copy a portion of self to an other array.
fun core_serialize_to(serializer: Serializer)

serialization :: Serializable :: core_serialize_to

Actual serialization of self to serializer
fun count(item: nullable Object): Int

core :: Collection :: count

How many occurrences of item are in the collection?
abstract fun enlarge(cap: Int)

core :: AbstractArray :: enlarge

Force the capacity to be at least cap.
init filled_with(value: E, count: Int)

core :: Array :: filled_with

Create an array of count elements
fun first: E

core :: Collection :: first

Return the first item of the collection
fun first=(item: E)

core :: Sequence :: first=

Set the first item.
init from(items: Collection[E])

core :: Array :: from

Create an array from a collection.
init from_deserializer(deserializer: Deserializer)

serialization :: Serializable :: from_deserializer

Create an instance of this class from the deserializer
fun get_class: CLASS

core :: Object :: get_class

The meta-object representing the dynamic type of self.
fun get_or_default(index: Int, default: E): E

core :: SequenceRead :: get_or_default

Try to get an element, return default if the index is invalid.
fun get_or_null(index: Int): nullable E

core :: SequenceRead :: get_or_null

Try to get an element, return null if the index is invalid.
fun group(group: MongoGroup): MongoPipeline

mongodb :: MongoPipeline :: group

Apply group
fun has(item: nullable Object): Bool

core :: Collection :: has

Is item in the collection ?
fun has_all(other: Collection[nullable Object]): Bool

core :: Collection :: has_all

Does the collection contain at least each element of other?
fun has_any(other: Collection[nullable Object]): Bool

core :: Collection :: has_any

Does the collection contain at least one element of other?
fun has_exactly(other: Collection[nullable Object]): Bool

core :: Collection :: has_exactly

Does the collection contain exactly all the elements of other?
fun has_only(item: nullable Object): Bool

core :: Collection :: has_only

Is the collection contain only item?
fun hash: Int

core :: Object :: hash

The hash code of the object.
fun index_of(item: nullable Object): Int

core :: SequenceRead :: index_of

The index of the first occurrence of item.
fun index_of_from(item: nullable Object, pos: Int): Int

core :: SequenceRead :: index_of_from

The index of the first occurrence of item, starting from pos.
init init

core :: Object :: init

abstract fun insert(item: E, index: Int)

core :: Sequence :: insert

Insert an element at a given position, following elements are shifted.
fun insert_all(coll: Collection[E], index: Int)

core :: Sequence :: insert_all

Insert all elements at a given position, following elements are shifted.
fun inspect: String

core :: Object :: inspect

Developer readable representation of self.
protected fun inspect_head: String

core :: Object :: inspect_head

Return "CLASSNAME:#OBJECTID".
fun is_empty: Bool

core :: Collection :: is_empty

Is there no item in the collection?
intern fun is_same_instance(other: nullable Object): Bool

core :: Object :: is_same_instance

Return true if self and other are the same instance (i.e. same identity).
fun is_same_serialized(other: nullable Object): Bool

core :: Object :: is_same_serialized

Is self the same as other in a serialization context?
intern fun is_same_type(other: Object): Bool

core :: Object :: is_same_type

Return true if self and other have the same dynamic type.
abstract fun iterator: Iterator[E]

core :: Collection :: iterator

Get a new iterator on the collection.
fun iterator_from(pos: Int): IndexedIterator[E]

core :: SequenceRead :: iterator_from

Gets a new Iterator starting at position pos
fun join(separator: nullable Text, last_separator: nullable Text): String

core :: Collection :: join

Concatenate and separate each elements with separator.
fun last: E

core :: SequenceRead :: last

Get the last item.
fun last=(item: E)

core :: Sequence :: last=

Set the last item.
fun last_index_of(item: nullable Object): Int

core :: SequenceRead :: last_index_of

The index of the last occurrence of item.
fun last_index_of_from(item: nullable Object, pos: Int): Int

core :: SequenceRead :: last_index_of_from

The index of the last occurrence of item starting from pos and decrementing.
fun length: Int

core :: Collection :: length

Number of items in the collection.
protected fun length=(length: Int)

core :: AbstractArrayRead :: length=

fun limit(number: nullable Int): MongoPipeline

mongodb :: MongoPipeline :: limit

Apply limit
fun match(query: MongoMatch): MongoPipeline

mongodb :: MongoPipeline :: match

Apply match
fun modulo(index: Int): E

core :: SequenceRead :: modulo

Return the index-th element but wrap
fun modulo=(index: Int, value: E)

core :: Sequence :: modulo=

Set the index-th element but wrap
fun modulo_index(index: Int): Int

core :: SequenceRead :: modulo_index

Returns the real index for a modulo index.
protected fun msgpack_extra_array_items: Int

serialization :: Serializable :: msgpack_extra_array_items

Hook to request a larger than usual metadata array
fun mutex: Mutex

core :: Array :: mutex

protected fun mutex=(mutex: Mutex)

core :: Array :: mutex=

fun not_empty: Bool

core :: Collection :: not_empty

Alias for not is_empty.
intern fun object_id: Int

core :: Object :: object_id

An internal hash code for the object based on its identity.
fun output

core :: Object :: output

Display self on stdout (debug only).
intern fun output_class_name

core :: Object :: output_class_name

Display class name on stdout (debug only).
fun permutations(r: Int): Collection[SequenceRead[E]]

core :: Collection :: permutations

All r-length permutations on self (all possible ordering) without repeated elements.
fun plain_to_s: String

core :: Collection :: plain_to_s

Concatenate elements without separators
abstract fun pop: E

core :: Sequence :: pop

Remove the last item.
fun prepend(coll: Collection[E])

core :: Sequence :: prepend

Add all items of coll before the first one.
fun product(r: Int): Collection[SequenceRead[E]]

core :: Collection :: product

Cartesian product, over r times self.
fun project(projection: JsonObject): MongoPipeline

mongodb :: MongoPipeline :: project

Apply projection
abstract fun push(e: E)

core :: Sequence :: push

Add an item after the last one.
fun rand: E

core :: Collection :: rand

Return a random element form the collection
abstract fun remove(item: nullable Object)

core :: RemovableCollection :: remove

Remove an occurrence of item
fun remove_all(item: nullable Object)

core :: RemovableCollection :: remove_all

Remove all occurrences of item
abstract fun remove_at(index: Int)

core :: Sequence :: remove_at

Remove the item at index and shift all following elements
abstract fun reverse_iterator: IndexedIterator[E]

core :: SequenceRead :: reverse_iterator

Gets an iterator starting at the end and going backwards
fun reverse_iterator_from(pos: Int): IndexedIterator[E]

core :: SequenceRead :: reverse_iterator_from

Gets an iterator on the chars of self starting from pos
fun reversed: Array[E]

core :: AbstractArrayRead :: reversed

Return a new array that is the reverse of self
fun rotate_left

core :: Sequence :: rotate_left

Rotates the elements of self once to the left
fun rotate_right

core :: Sequence :: rotate_right

Rotates the elements of self once to the right
fun sample(length: Int): Array[E]

core :: Collection :: sample

Return a new array made of (at most) length elements randomly chosen.
fun serialization_hash: Int

core :: Object :: serialization_hash

Hash value use for serialization
fun serialize_msgpack(plain: nullable Bool): Bytes

serialization :: Serializable :: serialize_msgpack

Serialize self to MessagePack bytes
fun serialize_to(serializer: Serializer)

serialization :: Serializable :: serialize_to

Serialize self to serializer
fun serialize_to_json(plain: nullable Bool, pretty: nullable Bool): String

serialization :: Serializable :: serialize_to_json

Serialize self to JSON
abstract fun shift: E

core :: Sequence :: shift

Remove the first item.
fun shuffle

core :: AbstractArray :: shuffle

Reorder randomly the elements in self.
fun skip(number: nullable Int): MongoPipeline

mongodb :: MongoPipeline :: skip

Apply skip
fun sort(projection: JsonObject): MongoPipeline

mongodb :: MongoPipeline :: sort

Apply sort
fun sort_fa: ForAbuser[CompareQuery[E]]

core :: Array :: sort_fa

Sort an array through a for abuse.
fun sort_with(f: Fun1[E, Comparable])

core :: Array :: sort_with

Sorts an array with a function.
fun sub(from: Int, count: Int): Array[E]

core :: AbstractArrayRead :: sub

Returns a sub-array containing count elements starting from from.
fun subarray(start: Int, len: Int): Array[E]

core :: Sequence :: subarray

Copy the content of self between start and len to a new Array.
fun swap_at(a: Int, b: Int)

core :: AbstractArray :: swap_at

Invert two elements in the array
intern fun sys: Sys

core :: Object :: sys

Return the global sys object, the only instance of the Sys class.
fun to_a: Array[E]

core :: Collection :: to_a

Build a new array from a collection
abstract fun to_concurrent: CONCURRENT

core :: Collection :: to_concurrent

Wraps self in a thread-safe collection
fun to_counter: Counter[E]

core :: Collection :: to_counter

Create and fill up a counter with the elements of `self.
fun to_curlslist: CURLSList

core :: Collection :: to_curlslist

Convert Collection[String] to CURLSList
fun to_json: String

serialization :: Serializable :: to_json

Serialize self to plain JSON
abstract fun to_jvalue(env: JniEnv): JValue

core :: Object :: to_jvalue

fun to_pretty_json: String

serialization :: Serializable :: to_pretty_json

Serialize self to plain pretty JSON
fun to_s: String

core :: Object :: to_s

User readable representation of self.
fun to_shuffle: Array[E]

core :: Collection :: to_shuffle

Return a new array made of elements in a random order.
abstract fun unshift(e: E)

core :: Sequence :: unshift

Add an item before the first one.
fun unwind(path: String): MongoPipeline

mongodb :: MongoPipeline :: unwind

Apply unwind
init with_capacity(cap: Int)

core :: Array :: with_capacity

Create an empty array with a given capacity.
init with_items(objects: E...)

core :: Array :: with_items

Create an array with some objects.
init with_native(nat: NativeArray[E], size: Int)

core :: Array :: with_native

Create a array filled with a given native array.
package_diagram mongodb::MongoPipeline MongoPipeline json::JsonArray JsonArray mongodb::MongoPipeline->json::JsonArray json::JsonSequenceRead JsonSequenceRead json::JsonArray->json::JsonSequenceRead core::Array Array json::JsonArray->core::Array ...json::JsonSequenceRead ... ...json::JsonSequenceRead->json::JsonSequenceRead ...core::Array ... ...core::Array->core::Array

Ancestors

abstract class AbstractArray[E: nullable Object]

core :: AbstractArray

Resizable one dimension array of objects.
abstract class AbstractArrayRead[E: nullable Object]

core :: AbstractArrayRead

One dimension array of objects.
class Array[E: nullable Object]

core :: Array

Resizable one dimension array of objects.
interface Cloneable

core :: Cloneable

Something that can be cloned
interface Collection[E: nullable Object]

core :: Collection

The root of the collection hierarchy.
class JsonSequenceRead[E: nullable Serializable]

json :: JsonSequenceRead

A sequence that can be translated into a JSON array.
interface Object

core :: Object

The root of the class hierarchy.
interface RemovableCollection[E: nullable Object]

core :: RemovableCollection

Items can be removed from this collection
interface Sequence[E: nullable Object]

core :: Sequence

Sequence are indexed collection.
interface SequenceRead[E: nullable Object]

core :: SequenceRead

Sequences are indexed collections.
interface Serializable

serialization :: Serializable

Instances of this class can be passed to Serializer::serialize
interface SimpleCollection[E: nullable Object]

core :: SimpleCollection

Items can be added to these collections.

Parents

class JsonArray

json :: JsonArray

A JSON array.

Class definitions

mongodb $ MongoPipeline
# Mongo pipelines are arrays of aggregation stages
#
# With the `MongoCollection::aggregate` method, pipeline stages appear in a array.
# Documents pass through the stages in sequence.
#
# ~~~json
# db.collection.aggregate( [ { <stage> }, ... ] )
# ~~~
#
# The MongoPipeline fluent interface can be used to bluid a pipeline:
# ~~~
# var pipeline = (new MongoPipeline).
#	match((new MongoMatch).eq("game", "nit")).
#	group((new MongoGroup("$game._id")).sum("nitcoins", "$game.nitcoins")).
#	sort((new MongoMatch).eq("nitcoins", -1)).
#	limit(10)
# ~~~
#
# The pipeline can then be used in an aggregation query:
# ~~~nitish
# collection.aggregate(pipeline)
# ~~~
#
# For more information read about MongoDB pipeline operators from the MongoDB
# official documentation: https://docs.mongodb.com/manual/reference/operator/aggregation/
class MongoPipeline
	super JsonArray

	# Add a stage to the pipeline
	#
	# https://docs.mongodb.com/manual/reference/operator/aggregation/#stage-operators
	#
	# Each stage is registered as:
	# ~~~json
	# { $<stage>: <json> }
	# ~~~
	fun add_stage(stage: String, json: Serializable): MongoPipeline do
		var obj = new JsonObject
		obj["${stage}"] = json
		add obj
		return self
	end

	# Apply projection
	#
	# https://docs.mongodb.com/manual/reference/operator/aggregation/project/#pipe._S_project
	#
	# Passes along the documents with only the specified fields to the next stage
	# in the pipeline.
	#
	# ~~~json
	# { $project: { <specifications> } }
	# ~~~
	#
	# The specified fields can be existing fields from the input documents or
	# newly computed fields.
	fun project(projection: JsonObject): MongoPipeline do return add_stage("project", projection)

	# Apply match
	#
	# https://docs.mongodb.com/manual/reference/operator/aggregation/match/
	#
	# Filters the documents to pass only the documents that match the specified
	# condition(s) to the next pipeline stage.
	#
	# ~~~json
	# { $match: { <query> } }
	# ~~~
	fun match(query: MongoMatch): MongoPipeline do return add_stage("match", query)

	# Apply sort
	#
	# https://docs.mongodb.com/manual/reference/operator/aggregation/sort/
	#
	# Sorts all input documents and returns them to the pipeline in sorted order.
	#
	# ~~~json
	# { $sort: { <projection> } }
	# ~~~
	fun sort(projection: JsonObject): MongoPipeline do return add_stage("sort", projection)

	# Apply skip
	#
	# https://docs.mongodb.com/manual/reference/operator/aggregation/skip/
	#
	# Skips over the specified number of documents that pass into the stage and
	# passes the remaining documents to the next stage in the pipeline.
	#
	# ~~~json
	# { $skip: { <number> } }
	# ~~~
	#
	# If `number == null` then no skip stage is generated
	fun skip(number: nullable Int): MongoPipeline do
		if number == null then return self
		return add_stage("skip", number)
	end

	# Apply limit
	#
	# https://docs.mongodb.com/manual/reference/operator/aggregation/limit/
	#
	# Limits the number of documents passed to the next stage in the pipeline.
	#
	# ~~~json
	# { $limit: { <number> } }
	# ~~~
	#
	# If `number == null` then no limit stage is generated
	fun limit(number: nullable Int): MongoPipeline do
		if number == null then return self
		return add_stage("limit", number)
	end

	# Apply group
	#
	# https://docs.mongodb.com/manual/reference/operator/aggregation/group/
	#
	# Groups documents by some specified expression and outputs to the next stage
	# a document for each distinct grouping.
	#
	# The output documents contain an `_id` field which contains the distinct
	# group by key.
	#
	# The output documents can also contain computed fields that hold the values
	# of some accumulator expression grouped by the `$group`'s `_id` field.
	# `$group` does not order its output documents.
	#
	# ~~~json
	# { $group: { <group> } }
	# ~~~
	fun group(group: MongoGroup): MongoPipeline do return add_stage("group", group)

	# Apply unwind
	#
	# https://docs.mongodb.com/manual/reference/operator/aggregation/unwind/
	#
	# Deconstructs an array field from the input documents to output a document
	# for each element.
	# Each output document is the input document with the value of the array
	# field replaced by the element.
	#
	# ~~~json
	# { $unwind: <field path> }
	# ~~~
	fun unwind(path: String): MongoPipeline do return add_stage("unwind", path)
end
lib/mongodb/queries.nit:350,1--496,3