gistfile1.vb

Public Class RenderUnit
    ' 1 inch = 72 points
    Public WidthPoints As Integer
    Public HeightPoints As Integer

    Public Items As IEnumerable
    Public FileName As String
End Class

Public Interface IPDFLayout
    Function Layout() As RenderUnit
End Interface

Public Interface IPDFLayoutHandler
    Function GeneratePDF(ByVal renderUnit As RenderUnit) As String
End Interface

Public Interface IDataSource
    Function GetData() As IEnumerable
End Interface

Public Class PDFGenerator

    Private ReadOnly layout As IPDFLayout
    Private ReadOnly layoutHandler As IPDFLayoutHandler
    Private ReadOnly dataSource As IDataSource

    Public Sub New(ByVal layout As IPDFLayout, ByVal layoutHandler As IPDFLayoutHandler, ByVal dataSource As IDataSource)
        Me.layout = layout
        Me.layoutHandler = layoutHandler
        Me.dataSource = dataSource
    End Sub

    Public Function Generate() As String
        Dim dataItems As IEnumerable = dataSource.GetData()
        Dim renderUnit As RenderUnit = layout.Layout()
        Return layoutHandler.GeneratePDF(renderUnit)
    End Function

End Class

Public Class USCanadaLayout
    Implements IPDFLayout

    Public Function Layout() As RenderUnit Implements IPDFLayout.Layout
        ' I am supposed to hardcode this into the function here?
        Dim heightInches As Integer = 4
        Dim widthInches As Integer = 6

        Dim renderUnit As New RenderUnit
        renderUnit.HeightPoints = heightInches * 72
        renderUnit.WidthPoints = widthInches * 72
        renderUnit.FileName = String.Concat(System.Guid.NewGuid.ToString().Replace("-", ""), ".pdf")
        Return renderUnit
    End Function

End Class

Public Class MannequinLayoutHandler
    Implements IPDFLayoutHandler

    Public Function GeneratePDF(ByVal renderUnit As RenderUnit) As String Implements IPDFLayoutHandler.GeneratePDF
        ' generate pdf here based on the renderUnit argument and return the generated filename
    End Function

End Class

Public Class MannequinDataSource
    Implements IDataSource

    Public Function GetData() As System.Collections.IEnumerable Implements IDataSource.GetData
        ' Note: How do I proceed here, if the data is coming from the client (js array via ajax)?
    End Function

End Class

' Is this correct? Quite a few interfaces, no?
Dim layout As IPDFLayout = New USCanadaLayout()
Dim layoutHandler As IPDFLayoutHandler = New MannequinLayoutHandler()
Dim dataSource As IDataSource = New MannequinDataSource()
Dim generator As New PDFGenerator(layout, layoutHandler, dataSource)
generator.Generate()