F# Factory Pattern

Factory Pattern

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// Factory Pattern
[<AbstractClassAttribute>]
type Connection() =
    abstract member Description :unit -> unit

type OracleConnection() =
    inherit Connection()
    override O.Description() = printfn "I'm Oracle Connection"

type SQLServerConnection() =
    inherit Connection()
    override O.Description() = printfn "I'm SQLServer Connection"

type MySQLConnection() =
    inherit Connection()
    override O.Description() = printfn "I'm MySQL Connection"

type Factory() =
    member O.CreateConnection( connName ) =
        match connName with
        | "Oracle" -> OracleConnection() :> Connection
        | "SQLServer" -> SQLServerConnection() :> Connection
        | "MySQL" -> MySQLConnection() :> Connection
        | _ -> failwith "No such connection "

// Testing
let factory = Factory()
let connection = "Oracle" |> factory.CreateConnection
connection.Description()

Multiple items
type AbstractClassAttribute =
inherit Attribute
new : unit -> AbstractClassAttribute

Full name: Microsoft.FSharp.Core.AbstractClassAttribute

--------------------
new : unit -> AbstractClassAttribute

Multiple items
type Connection =
new : unit -> Connection
abstract member Description : unit -> unit

Full name: Script.Connection

--------------------
new : unit -> Connection

abstract member Connection.Description : unit -> unit

Full name: Script.Connection.Description

type unit = Unit

Full name: Microsoft.FSharp.Core.unit

Multiple items
type OracleConnection =
  inherit Connection
  new : unit -> OracleConnection
  override Description : unit -> unit

Full name: Script.OracleConnection

--------------------
new : unit -> OracleConnection

val O : OracleConnection

override OracleConnection.Description : unit -> unit

Full name: Script.OracleConnection.Description

val printfn : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printfn

Multiple items
type SQLServerConnection =
  inherit Connection
  new : unit -> SQLServerConnection
  override Description : unit -> unit

Full name: Script.SQLServerConnection

--------------------
new : unit -> SQLServerConnection

val O : SQLServerConnection

override SQLServerConnection.Description : unit -> unit

Full name: Script.SQLServerConnection.Description

Multiple items
type MySQLConnection =
  inherit Connection
  new : unit -> MySQLConnection
  override Description : unit -> unit

Full name: Script.MySQLConnection

--------------------
new : unit -> MySQLConnection

val O : MySQLConnection

override MySQLConnection.Description : unit -> unit

Full name: Script.MySQLConnection.Description

Multiple items
type Factory =
new : unit -> Factory
member CreateConnection : connName:string -> Connection

Full name: Script.Factory

--------------------
new : unit -> Factory

val O : Factory

member Factory.CreateConnection : connName:string -> Connection

Full name: Script.Factory.CreateConnection

val connName : string

val failwith : message:string -> 'T

Full name: Microsoft.FSharp.Core.Operators.failwith

val factory : Factory

Full name: Script.factory

val connection : Connection

Full name: Script.connection

member Factory.CreateConnection : connName:string -> Connection

abstract member Connection.Description : unit -> unit

Raw view Test code New version

More information

Link:	http://fssnip.net/k6
Posted:	11 years ago
Author:	Evanescent Devil
Tags:	design patterns , factory pattern