Emmanuele Sassi
83 lines
2.6 KiB
VB.net
83 lines
2.6 KiB
VB.net
Imports System.ComponentModel.Composition
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Imports System.ComponentModel.Composition.Hosting
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Imports Effector.Plugin.Interface
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Public Class MEFLoader
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Private importers As Dictionary(Of String, List(Of Object)) = New Dictionary(Of String, List(Of Object))()
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Public Overridable Function LoadByTag(Of T)(ByVal path As String, ByVal tag As String) As ICollection(Of T)
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Dim importer = GetImporter(Of T)(path)
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Return importer.LoadByMEF(path, tag)
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End Function
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Protected Function GetImporter(Of T)(ByVal path As String) As MEFImporter(Of T)
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Dim importerList = GetImporterList(path)
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Dim importer = importerList.OfType(Of MEFImporter(Of T))().FirstOrDefault()
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If importer Is Nothing Then
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importer = New MEFImporter(Of T)(path)
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importerList.Add(importer)
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End If
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Return importer
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End Function
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Protected Function GetImporterList(ByVal path As String) As List(Of Object)
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If importers.ContainsKey(path) = False Then importers.Add(path, New List(Of Object)())
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Return importers(path)
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End Function
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Public Overridable Function LoadByType(Of T)(ByVal path As String) As ICollection(Of T)
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Return LoadByTag(Of T)(path, String.Empty)
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End Function
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End Class
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Public Interface IMetadata
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ReadOnly Property Name As String
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End Interface
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Public Class MEFImporter(Of T)
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<ImportMany(AllowRecomposition:=True)>
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Public Property [imports] As IEnumerable(Of Lazy(Of T, IMetadata))
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<Export>
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Public Property SupervisorFunctions As IHost
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Private Sub New()
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End Sub
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Public Sub New(ByVal path As String)
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Me.New()
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directoryCatalog = New DirectoryCatalog(path)
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End Sub
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Protected directoryCatalog As DirectoryCatalog = Nothing
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Protected Sub DoImport(ByVal path As String)
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Dim catalog = New AggregateCatalog()
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catalog.Catalogs.Add(directoryCatalog)
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'catalog.Catalogs.Add(New AssemblyCatalog(System.Reflection.Assembly.GetCallingAssembly()))
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catalog.Catalogs.Add(New AssemblyCatalog(System.Reflection.Assembly.GetExecutingAssembly()))
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Dim container As CompositionContainer = New CompositionContainer(catalog)
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Me.SupervisorFunctions = New SupervisorFunctions
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container.ComposeParts(Me)
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End Sub
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Public Function LoadByMEF(ByVal path As String, ByVal name As String) As ICollection(Of T)
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Dim res = New List(Of T)()
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DoImport(path)
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For Each [module] As Lazy(Of T, IMetadata) In [imports]
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If [module].Metadata.Name = name OrElse String.IsNullOrEmpty(name) Then
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res.Add([module].Value)
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End If
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Next
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Return res
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End Function
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End Class
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