trait Cursor[T] extends CursorCompatAPI[T]
Cursor over results from MongoDB.
import scala.concurrent.{ ExecutionContext, Future } import reactivemongo.api.Cursor import reactivemongo.api.bson.{ BSONDocument, Macros } import reactivemongo.api.bson.collection.BSONCollection case class User(name: String, pass: String) implicit val handler = Macros.reader[User] def findUsers(coll: BSONCollection)( implicit ec: ExecutionContext): Future[List[User]] = coll.find(BSONDocument("enabled" -> true)). cursor[User](). // obtain cursor for User results collect[List]( maxDocs = 10, err = Cursor.FailOnError[List[User]]())
- T
the type parsed from each result document
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Abstract Value Members
- abstract def collect[M[_]](maxDocs: Int, err: ErrorHandler[M[T]])(implicit cbf: Factory[T, M[T]], ec: ExecutionContext): Future[M[T]]
Collects all the documents into a collection of type
M[T]
.Collects all the documents into a collection of type
M[T]
.- maxDocs
the maximum number of documents to be retrieved (-1 for unlimited).
- err
The binary operator to be applied when failing to get the next response. Exception or Fail raised within the
suc
function cannot be recovered by this error handler.import scala.concurrent.ExecutionContext import reactivemongo.api.Cursor import reactivemongo.api.bson.BSONDocument import reactivemongo.api.bson.collection.BSONCollection def foo(collection: BSONCollection, query: BSONDocument)( implicit ec: ExecutionContext) = { val cursor = collection.find(query).cursor[BSONDocument]() // return the 3 first documents in a Vector[BSONDocument]. cursor.collect[Vector](3, Cursor.FailOnError[Vector[BSONDocument]]()) }
- Definition Classes
- CursorCompatAPI
- abstract def foldBulks[A](z: => A, maxDocs: Int = -1)(suc: (A, Iterator[T]) => State[A], err: ErrorHandler[A] = FailOnError[A]())(implicit ec: ExecutionContext): Future[A]
Applies a binary operator to a start value and all bulks of documents retrieved by this cursor, going first to last.
Applies a binary operator to a start value and all bulks of documents retrieved by this cursor, going first to last.
- A
the result type of the binary operator
import reactivemongo.api.Cursor import scala.concurrent.ExecutionContext case class Person(name: String, age: Int) def foo(cursor: Cursor[Person])(implicit ec: ExecutionContext) = cursor.foldBulks(Nil: Seq[Person])( (s, bulk: Iterator[Person]) => Cursor.Cont(s ++ bulk), { (l, e) => println("last valid value: " + l); Cursor.Fail(e) })
- z
the initial value
- maxDocs
the maximum number of documents to be retrieved (-1 for unlimited). The actual document count can exceed this, when this maximum devided by the batch size given a non-zero remainder.
- suc
The binary operator to be applied when the next response is successfully read.
- err
The binary operator to be applied when failing to get the next response. Exception or Fail raised within the
suc
function cannot be recovered by this error handler.
- abstract def foldBulksM[A](z: => A, maxDocs: Int = -1)(suc: (A, Iterator[T]) => Future[State[A]], err: ErrorHandler[A] = FailOnError[A]())(implicit ec: ExecutionContext): Future[A]
Applies a binary operator to a start value and all bulks of documents retrieved by this cursor, going first to last.
Applies a binary operator to a start value and all bulks of documents retrieved by this cursor, going first to last.
- A
the result type of the binary operator
import scala.concurrent.{ ExecutionContext, Future } import reactivemongo.api.Cursor case class Person(name: String, age: Int) def foo(cursor: Cursor[Person])(implicit ec: ExecutionContext) = cursor.foldBulksM(Nil: Seq[Person])( { (s, bulk: Iterator[Person]) => Future.successful(Cursor.Cont(s ++ bulk)) }, { (l, e) => println("last valid value: " + l) Cursor.Fail[Seq[Person]](e) })
- z
the initial value
- maxDocs
the maximum number of documents to be retrieved (-1 for unlimited). The actual document count can exceed this, when this maximum devided by the batch size given a non-zero remainder.
- suc
The binary operator to be applied when the next response is successfully read. This must be safe, and any error must be returned as
Future.failed[State[A]]
.- err
The binary operator to be applied when failing to get the next response. Exception or Fail raised within the
suc
function cannot be recovered by this error handler.
- abstract def foldWhile[A](z: => A, maxDocs: Int = -1)(suc: (A, T) => State[A], err: ErrorHandler[A] = FailOnError[A]())(implicit ec: ExecutionContext): Future[A]
Applies a binary operator to a start value and all elements retrieved by this cursor, going first to last.
Applies a binary operator to a start value and all elements retrieved by this cursor, going first to last.
- A
the result type of the binary operator
import reactivemongo.api.Cursor import scala.concurrent.ExecutionContext case class Person(name: String, age: Int) def foo(cursor: Cursor[Person])(implicit ec: ExecutionContext) = cursor.foldWhile(Nil: Seq[Person])((s, p) => Cursor.Cont(s :+ p), { (l, e) => println("last valid value: " + l); Cursor.Fail(e) })
- z
the initial value
- maxDocs
the maximum number of documents to be retrieved (-1 for unlimited).
- suc
The binary operator to be applied when the next document is successfully read.
- err
The binary operator to be applied when failing to get the next response. Exception or Fail raised within the
suc
function cannot be recovered by this error handler.
- abstract def foldWhileM[A](z: => A, maxDocs: Int = -1)(suc: (A, T) => Future[State[A]], err: ErrorHandler[A] = FailOnError[A]())(implicit ec: ExecutionContext): Future[A]
Applies a binary operator to a start value and all elements retrieved by this cursor, going first to last.
Applies a binary operator to a start value and all elements retrieved by this cursor, going first to last.
- A
the result type of the binary operator
import scala.concurrent.{ ExecutionContext, Future } import reactivemongo.api.Cursor case class Person(name: String, age: Int) def foo(cursor: Cursor[Person])(implicit ec: ExecutionContext) = cursor.foldWhileM(Nil: Seq[Person])( (s, p) => Future.successful(Cursor.Cont(s :+ p)), { (l, e) => println("last valid value: " + l) Cursor.Fail[Seq[Person]](e) })
- z
the initial value
- maxDocs
the maximum number of documents to be retrieved (-1 for unlimited).
- suc
The binary operator to be applied when the next document is successfully read. This must be safe, and any error must be returned as
Future.failed[State[A]]
.- err
The binary operator to be applied when failing to get the next response. Exception or Fail raised within the
suc
function cannot be recovered by this error handler.
- abstract def head(implicit ec: ExecutionContext): Future[T]
Returns the first document matching the query, or fails with Cursor.NoSuchResultException if none.
Returns the first document matching the query, or fails with Cursor.NoSuchResultException if none.
import scala.concurrent.{ ExecutionContext, Future } import reactivemongo.bson.BSONDocument import reactivemongo.api.collections.bson.BSONCollection def first(query: BSONDocument)(collection: BSONCollection)( implicit ec: ExecutionContext): Future[BSONDocument] = { val cursor = collection.find(query).cursor[BSONDocument]() // return option of the first element. cursor.head }
- abstract def headOption(implicit ec: ExecutionContext): Future[Option[T]]
Returns the first document matching the query, if any.
Returns the first document matching the query, if any.
import scala.concurrent.{ ExecutionContext, Future } import reactivemongo.api.bson.BSONDocument import reactivemongo.api.bson.collection.BSONCollection def maybeFirst(query: BSONDocument)(collection: BSONCollection)( implicit ec: ExecutionContext): Future[Option[BSONDocument]] = { val cursor = collection.find(query).cursor[BSONDocument]() // return option of the first element. cursor.headOption }
- abstract def foldResponses[A](z: => A, maxDocs: Int = -1)(suc: (A, Response) => State[A], err: ErrorHandler[A] = FailOnError[A]())(implicit ec: ExecutionContext): Future[A]
Applies a binary operator to a start value and all responses handled by this cursor, going first to last.
Applies a binary operator to a start value and all responses handled by this cursor, going first to last.
- A
the result type of the binary operator
- z
the initial value
- maxDocs
the maximum number of documents to be retrieved (-1 for unlimited). The actual document count can exceed this, when this maximum devided by the batch size given a non-zero remainder.
- suc
The binary operator to be applied when the next response is successfully read.
- err
The binary operator to be applied when failing to get the next response. Exception or Fail raised within the
suc
function cannot be recovered by this error handler.
- Annotations
- @deprecated
- Deprecated
(Since version 0.19.4) Internal: will be made private
- abstract def foldResponsesM[A](z: => A, maxDocs: Int = -1)(suc: (A, Response) => Future[State[A]], err: ErrorHandler[A] = FailOnError[A]())(implicit ec: ExecutionContext): Future[A]
Applies a binary operator to a start value and all responses handled by this cursor, going first to last.
Applies a binary operator to a start value and all responses handled by this cursor, going first to last.
- A
the result type of the binary operator
- z
the initial value
- maxDocs
the maximum number of documents to be retrieved (-1 for unlimited). The actual document count can exceed this, when this maximum devided by the batch size given a non-zero remainder.
- suc
The binary operator to be applied when the next response is successfully read. This must be safe, and any error must be returned as
Future.failed[State[A]]
.- err
The binary operator to be applied when failing to get the next response. Exception or Fail raised within the
suc
function cannot be recovered by this error handler.
- Annotations
- @deprecated
- Deprecated
(Since version 0.19.4) Internal: will be made private
Concrete Value Members
- final def !=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- final def ##(): Int
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- AnyRef → Any
- def +(other: String): String
- def ->[B](y: B): (Cursor[T], B)
- final def ==(arg0: Any): Boolean
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- final def asInstanceOf[T0]: T0
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- def clone(): AnyRef
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- @throws(classOf[java.lang.CloneNotSupportedException]) @native() @HotSpotIntrinsicCandidate()
- def ensuring(cond: (Cursor[T]) => Boolean, msg: => Any): Cursor[T]
- def ensuring(cond: (Cursor[T]) => Boolean): Cursor[T]
- def ensuring(cond: Boolean, msg: => Any): Cursor[T]
- def ensuring(cond: Boolean): Cursor[T]
- final def eq(arg0: AnyRef): Boolean
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- AnyRef
- def equals(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef → Any
- def fold[A](z: => A, maxDocs: Int = -1)(suc: (A, T) => A)(implicit ec: ExecutionContext): Future[A]
Applies a binary operator to a start value and all elements retrieved by this cursor, going first to last.
Applies a binary operator to a start value and all elements retrieved by this cursor, going first to last.
- A
the result type of the binary operator
import scala.concurrent.ExecutionContext import reactivemongo.api.Cursor case class Person(name: String, age: Int) def foo(cursor: Cursor[Person])(implicit ec: ExecutionContext) = cursor.foldWhile(Nil: Seq[Person])((s, p) => Cursor.Cont(s :+ p), { (l, e) => println("last valid value: " + l); Cursor.Fail(e) })
- z
the initial value
- maxDocs
the maximum number of documents to be retrieved (-1 for unlimited).
- suc
The binary operator to be applied when the next document is successfully read.
- def formatted(fmtstr: String): String
- final def getClass(): Class[_ <: AnyRef]
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- @native() @HotSpotIntrinsicCandidate()
- def hashCode(): Int
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- final def wait(): Unit
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- def finalize(): Unit
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- Deprecated
(Since version ) see corresponding Javadoc for more information.
- def →[B](y: B): (Cursor[T], B)
- Implicit
- This member is added by an implicit conversion from Cursor[T] toArrowAssoc[Cursor[T]] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @deprecated
- Deprecated
(Since version 2.13.0) Use
->
instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.