simple ioc

gistfile1.fs

open System
open System.Linq
open System.Collections.Generic
open System.Collections.Concurrent
open Microsoft.FSharp.Collections
open System.Reflection

type Container() =
    let _map = new HashMultiMap<Type,Type>(HashIdentity.Structural)
    let _activated = new ConcurrentDictionary<Type, obj>()

    member x.Add(contract, impl) = 
        _map.Add(contract, impl)

    member x.Add<'A,'B>() = 
        x.Add(typeof<'A>, typeof<'B>)

    member x.New(impl: Type, traces: Stack<Type>) = 
        let con = impl.GetConstructors().[0]
        let ps = con.GetParameters()
        let args : obj array = Array.zeroCreate ps.Length

        traces.Push(impl)

        for i = 0 to ps.Length - 1 do
            let pt = ps.[i]
            args.[i] <- x.Get (pt.ParameterType, traces)

        ignore(traces.Pop())
        con.Invoke(args)       
          
    member x.InternalGet(impl, traces) = 
        _activated.GetOrAdd (impl, fun k -> x.New(impl, traces))        

    member x.GetAll (t, traces) = 
        let list = _map.FindAll t
        [|for tmp in list do
            yield x.InternalGet(tmp, traces)|]     

    member x.Get(contract, traces) =         
        let list = _map.FindAll contract        
        match list.IsEmpty with 
            | true -> 
                    if contract.IsArray 
                        then 
                            let elementType = contract.GetElementType()
                            let all = x.GetAll(elementType, traces)
                            all.CastTo(elementType) :> obj
                        else null 
            |  false -> x.InternalGet(list.Head, traces)

    member x.Get(contract) = 
        x.Get(contract, new Stack<Type>())
        
    member x.Get<'T>() = 
        x.Get(typeof<'T>) :?> 'T