reactivemongo-bson-api
API
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reactivemongo-bson-api/reactivemongo.api.bson/BSONReader

BSONReader

reactivemongo.api.bson.BSONReader
See theBSONReader companion object
trait BSONReader[T]

A reader that produces an instance of T from a subtype of BSONValue.

Attributes

Companion:
object
Graph
Supertypes
class Object
trait Matchable
class Any
Known subtypes
object Handler.type
object Handler.type
trait BSONHandler[T]
object BSONBinaryHandler.type
object BSONBooleanHandler.type
object BSONByteHandler.type
object BSONCharHandler.type
object BSONDecimalHandler.type
object BSONDoubleHandler.type
object BSONFloatHandler.type
object BSONIntegerHandler.type
object BSONLocaleHandler.type
object BSONLongHandler.type
object BSONShortHandler.type
object BSONStringHandler.type
object BSONURIHandler.type
object BSONURLHandler.type
object BSONUUIDHandler.type
object Handler.type
Self type

Members list

Concise view

Value members

Abstract methods

def readTry(bson: BSONValue): Try[T]

Tries to produce an instance of T from the bson value.

Tries to produce an instance of T from the bson value.

import scala.util.Try
import reactivemongo.api.bson.{ BSONReader, BSONValue }

def fromBSON[T](bson: BSONValue)(implicit r: BSONReader[T]): Try[T] =
 r.readTry(bson)

Attributes

Concrete methods

def afterRead[U](f: T => U): BSONReader[U]

Prepares a BSONReader that returns the result of applying f on the result of this reader.

Prepares a BSONReader that returns the result of applying f on the result of this reader.

import scala.util.Try
import reactivemongo.api.bson.{ BSONReader, BSONValue }

// Try to return an integer + 1,
// from any T that can be read from BSON
// and is a numeric type
def fromBSON[T](bson: BSONValue)(
 implicit r: BSONReader[T], n: Numeric[T]): Try[Int] = {
 val r2: BSONReader[Int] = r.afterRead { v => n.toInt(v) + 1 }
 r2.readTry(bson)
}

Attributes

f

the function to apply

def beforeRead(f: PartialFunction[BSONValue, BSONValue]): BSONReader[T]

Prepares a BSONReader that transforms the input BSON value, using the given f function, before passing the transformed BSON value to the current reader.

Prepares a BSONReader that transforms the input BSON value, using the given f function, before passing the transformed BSON value to the current reader.

import reactivemongo.api.bson.{
 BSONReader, BSONInteger, BSONNull, BSONString
}

val normalizingReader: BSONReader[Int] =
 implicitly[BSONReader[Int]].beforeRead {
   case BSONNull => BSONInteger(-1)
   case BSONString(s) => BSONInteger(s.size)
   // other values are unchanged
 }

normalizingReader.readOpt(BSONNull) // Some(-1)
normalizingReader.readTry(BSONString("foo")) // Success(3)
normalizingReader.readOpt(BSONInteger(4)) // unchanged: Some(4)

Attributes

def beforeReadTry(f: BSONValue => Try[BSONValue]): BSONReader[T]

Prepares a BSONReader that transforms the input BSON value, using the given f function, before passing the transformed BSON value to the current reader.

Prepares a BSONReader that transforms the input BSON value, using the given f function, before passing the transformed BSON value to the current reader.

Attributes

def readOpt(bson: BSONValue): Option[T]

Tries to produce an instance of T from the bson value, returns None if an error occurred.

Tries to produce an instance of T from the bson value, returns None if an error occurred.

import reactivemongo.api.bson.{ BSONReader, BSONValue }

def fromBSON[T](bson: BSONValue)(implicit r: BSONReader[T]): Option[T] =
 r.readOpt(bson)

Attributes

def readOrElse(bson: BSONValue, default: => T): T

Tries to produce an instance of T from the bson value, returns the default value if an error occurred.

Tries to produce an instance of T from the bson value, returns the default value if an error occurred.

import reactivemongo.api.bson.{ BSONReader, BSONValue }

def fromBSON[T](bson: BSONValue, v: T)(implicit r: BSONReader[T]): T =
 r.readOrElse(bson, v)

Attributes

def widen[U >: T]: BSONReader[U]

Widens this reader for a compatible type U.

Widens this reader for a compatible type U.

import reactivemongo.api.bson.BSONReader

val listReader: BSONReader[List[String]] =
 implicitly[BSONReader[List[String]]]

val widenAsSeqReader: BSONReader[Seq[String]] =
 listReader.widen[Seq[String]]
 // as Seq[String] >: List[String]

Attributes

U

must be a super-type of T

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