Packages

  • package root
    Definition Classes
    root
  • package com
    Definition Classes
    root
  • package twitter

    Start with com.twitter.finagle.

    Start with com.twitter.finagle.

    Definition Classes
    com
  • package finagle

    Finagle is an extensible RPC system.

    Finagle is an extensible RPC system.

    Services are represented by class com.twitter.finagle.Service. Clients make use of com.twitter.finagle.Service objects while servers implement them.

    Finagle contains a number of protocol implementations; each of these implement Client and/or com.twitter.finagle.Server. For example, Finagle's HTTP implementation, com.twitter.finagle.Http (in package finagle-http), exposes both.

    Thus a simple HTTP server is built like this:

    import com.twitter.finagle.{Http, Service}
import com.twitter.finagle.http.{Request, Response}
import com.twitter.util.{Await, Future}

val service = new Service[Request, Response] {
  def apply(req: Request): Future[Response] =
    Future.value(Response())
}
val server = Http.server.serve(":8080", service)
Await.ready(server)

    We first define a service to which requests are dispatched. In this case, the service returns immediately with a HTTP 200 OK response, and with no content.

    This service is then served via the Http protocol on TCP port 8080. Finally we wait for the server to stop serving.

    We can now query our web server:

    % curl -D - localhost:8080
HTTP/1.1 200 OK

    Building an HTTP client is also simple. (Note that type annotations are added for illustration.)

    import com.twitter.finagle.{Http, Service}
import com.twitter.finagle.http.{Request, Response}
import com.twitter.util.{Future, Return, Throw}

val client: Service[Request, Response] = Http.client.newService("localhost:8080")
val f: Future[Response] = client(Request()).respond {
  case Return(rep) =>
    printf("Got HTTP response %s\n", rep)
  case Throw(exc) =>
    printf("Got error %s\n", exc)
}

    Http.client.newService("localhost:8080") constructs a new com.twitter.finagle.Service instance connected to localhost TCP port 8080. We then issue a HTTP/1.1 GET request to URI "/". The service returns a com.twitter.util.Future representing the result of the operation. We listen to this future, printing an appropriate message when the response arrives.

    The Finagle homepage contains useful documentation and resources for using Finagle.

    Definition Classes
    twitter
  • package postgresql
    Definition Classes
    finagle
  • package types
    Definition Classes
    postgresql
  • Json
  • Kind
  • PgDate
  • PgNumeric
  • PgTime
  • PgType
  • ValueReads
  • ValueWrites

trait ValueReads[T] extends AnyRef

Typeclass for decoding wire values to Scala/Java types.

Postgres has its own type system, so the mapping of postgres types to scala types is not 1:1. Furthermore, postgres allows creating custom types (i.e.: commonly enums, but any arbitrary type can effectively be created) which also require their own mapping to scala types.

The following built-in types and their corresponding scala / java types are provided (read this table as "Postgres Type X can be read into Scala / Java Type Y"):

Postgres Type

Scala / Java Type

BIGINT (int8)

Long

BOOL

Boolean

BYTEA (byte[])

Buf

CHARACTER(n)

String

DATE (date)

java.time.LocalDate

DOUBLE (float8)

Double

INET

Inet (java.net.InetAddress and a subnet)

INTEGER (int, int4)

Int and Long

JSON

String or Json

JSONB

Json

NUMERIC (decimal)

BigDecimal

REAL (float4)

Float and Double

SMALLINT (int2)

Short, Int and Long. As well as Byte (bounds are checked), since Postgres doesn't have int1.

TEXT

String

TIMESTAMP

java.time.Instant

TIMESTAMP WITH TIME ZONE

java.time.Instant

UUID

java.util.UUID

VARCHAR

String

Note

numeric types don't have the same correspondence for reading and writing.

See also

ValueWrites

PgType

Linear Supertypes
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Abstract Value Members

  1. abstract def accepts(tpe: PgType): Boolean

    Returns true if this typeclass is able to decode a wire value of the specified type.

    Returns true if this typeclass is able to decode a wire value of the specified type.

    tpe

    the type of the wire value to decode.

    returns

    true if this typeclass can decode the value, false otherwise.

  2. abstract def reads(tpe: PgType, buf: Buf, charset: Charset): T

    Decodes a non-null value from the wire, throwing an exception if the decoding fails.

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  5. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  6. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  7. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  8. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  9. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  10. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  11. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  12. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  13. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  14. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  15. def orElse(that: ValueReads[T]): ValueReads[T]

    Returns a ValueReads instance that will use this if it accepts the type, otherwise will delegate to that.

    Returns a ValueReads instance that will use this if it accepts the type, otherwise will delegate to that.

    that

    the instance to delegate to when this does not accept the provided type.

    returns

    a ValueReads instance that will use this if it accepts the type, otherwise will delegate to that.

    See also

    ValueReads.or

  16. def reads(tpe: PgType, value: WireValue, charset: Charset): T

    Decode a potentially NULL wire value into the requested scala type.

    Decode a potentially NULL wire value into the requested scala type. Note that no further validation is done on the passed in PgType, the client is expected to have invoked accepts first. Not respecting this may lead to successfully reading an invalid value.

    tpe

    the postgres type to decode (used when the typeclass supports more than one).

    value

    the value on the wire. This may be NULL.

    charset

    the server's character set (necessary for decoding strings).

    returns

    the decoded value or an exception

  17. def readsNull(tpe: PgType): T

    Produce the value corresponding to the SQL NULL.

    Produce the value corresponding to the SQL NULL. Note that typically, there is no sensical value (i.e.: there's no Int value to produce for a NULL), thus this method has a default implementation of producing an error.

  18. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  19. def toString(): String
    Definition Classes
    AnyRef → Any
  20. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  21. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  22. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()

Inherited from AnyRef

Inherited from Any

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