reactivemongo-bson-api
API
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reactivemongo-bson-api/reactivemongo.api.bson/BSONHandler

BSONHandler

reactivemongo.api.bson.BSONHandler
See theBSONHandler companion object
trait BSONHandler[T] extends BSONReader[T], BSONWriter[T]

A BSON handler is able to both read and write T values from/to BSON representation.

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

def roundtrip[T](value: T)(implicit handler: BSONHandler[T]): Try[Boolean] =
 for {
   bson: BSONValue <- handler.writeTry(value)
   dser <- handler.readTry(bson)
 } yield (dser == value) // true

Attributes

Companion
object
Graph
Supertypes
trait BSONWriter[T]
trait BSONReader[T]
class Object
trait Matchable
class Any
Known subtypes
object Handler
Show all

Members list

Value members

Concrete methods

final override def afterWrite(f: PartialFunction[BSONValue, BSONValue]): BSONHandler[T]

Prepares a BSON writer that returns the result of applying f on the BSON value from this writer.

Prepares a BSON writer that returns the result of applying f on the BSON value from this writer.

If the f function is not defined for a BSONValue, it will results in a Failure.

Value parameters

f

the partial function to apply

Attributes

Definition Classes
final override def afterWriteTry(f: BSONValue => Try[BSONValue]): BSONHandler[T]

Prepares a BSON writer that returns the result of applying f on the BSON value from this writer.

Prepares a BSON writer that returns the result of applying f on the BSON value from this writer.

Value parameters

f

the safe function to apply

Attributes

Definition Classes
final def as[R](to: T => R, from: R => T): BSONHandler[R]
final override def beforeRead(f: PartialFunction[BSONValue, BSONValue]): BSONHandler[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

Definition Classes
final override def beforeReadTry(f: BSONValue => Try[BSONValue]): BSONHandler[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

Definition Classes
override def narrow[U <: T]: BSONHandler[U]

Narrows this writer for a compatible type U.

Narrows this writer for a compatible type U.

import reactivemongo.api.bson.BSONWriter

val listWriter: BSONWriter[Seq[String]] =
 implicitly[BSONWriter[Seq[String]]]

val narrowAsListWriter: BSONWriter[List[String]] =
 listWriter.narrow[List[String]]
 // as List[String] <: Seq[String]

Type parameters

U

must be a sub-type of T

Attributes

Definition Classes
override def widen[U >: T]: BSONHandler[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]

Type parameters

U

must be a super-type of T

Attributes

Definition Classes

Inherited 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)
}

Value parameters

f

the function to apply

Attributes

Inherited from:
BSONReader
def beforeWrite[U](f: U => T): BSONWriter[U]

Prepares a BSON writer that converts the input before calling the current writer.

Prepares a BSON writer that converts the input before calling the current writer.

Value parameters

f

the function apply the U input value to convert at T value used to the current writer

import reactivemongo.api.bson.BSONWriter
val w: BSONWriter[String] =
 implicitly[BSONWriter[Int]].beforeWrite(_.size)
w.writeTry("foo") // Success: BSONInteger(3)

Attributes

Inherited from:
BSONWriter
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

Inherited from:
BSONReader
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

Inherited from:
BSONReader
def writeOpt(t: T): Option[BSONValue]

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

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

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

def maybeBSON[T](value: T)(implicit w: BSONWriter[T]): Option[BSONValue] =
 w.writeOpt(value)

Attributes

Inherited from:
BSONWriter

Inherited and 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

Inherited from:
BSONReader
def writeTry(t: T): Try[BSONValue]

Tries to produce a BSON value from an instance of T.

Tries to produce a BSON value from an instance of T.

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

def toBSON[T](value: T)(implicit w: BSONWriter[T]): Try[BSONValue] =
 w.writeTry(value)

Attributes

Inherited from:
BSONWriter
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