CH A PT E R 1 0 ■ L E A R N I N G A B O U T P E R S IS T E N CE 271 The IBinary2TextProcessor interface has a single method； Process（）； which has two param eters： the binary stream and the text stream。 The implementation of IBinary2TextProcessor would be responsible for reading the data from the binary stream and saving data to the text stream。 The text…to…binary interface； IText2BinaryProcessor； follows a similar interface design； except that the input and output stream types are reversed。 Imports System。IO Public Interface IText2BinaryProcessor Sub Process（ByVal input As TextReader； ByVal output As Stream） End Interface The idea of both interface declarations is to focus on transferring data from one stream to another。 The shell for both data stream interfaces is very similar to the shell of the text…processing stream； except that binary and text streams are involved。 The TextProcessor shell was respon sible for knowing if the data stream was from the console or from a file。 When manipulating binary streams； the source still needs to be ascertained； but instead of creating text streams； binary streams are created。 If you understand the mechanics of using a text stream； you will understand the mechanics of using a binary stream。 The following is the plete implementation of the text…to…binary bootstrap class。 Imports System。IO Public Module Text2BinaryBootstrap Public Sub DisplayHelp（） Console。WriteLine（〃You need help？ Right now？〃） End Sub Public Sub Start（ByVal args As String（）； _ ByVal processor As IText2BinaryProcessor） #If DEBUG_OUTPUT Then Console。WriteLine（〃Argument count（〃 & args。Length & 〃）〃） For Each argument As String In args Console。WriteLine（〃Argument （〃 & argument & 〃）〃） Next #End If Dim reader As TextReader = Nothing Dim writer As Stream = Nothing If args。Length = 0 Then reader = Console。In writer = Console。OpenStandardOutput（） ElseIf args。Length = 1 Then If args（0） = 〃…help〃 Then Text2BinaryBootstrap。DisplayHelp（） Return End If …………………………………………………………Page 294…………………………………………………………… 272 CH AP T E R 1 0 ■ L E A R N I N G A B OU T P E R S IS TE N CE reader = File。OpenText（args（0）） writer = Console。OpenStandardOutput（） ElseIf args。Length = 2 Then If args（0） 〃…out〃 Then Text2BinaryBootstrap。DisplayHelp（） Return End If reader = Console。In writer = File。Open（args（1）； FileMode。Create） ElseIf args。Length = 3 Then If args（0） 〃…out〃 Then Text2BinaryBootstrap。DisplayHelp（） Return End If reader = File。OpenText（args（2）） writer = File。Open（args（1）； FileMode。Create） Else Text2BinaryBootstrap。DisplayHelp（） Return End If processor。Process（reader； writer） writer。Close（） End Sub End Module The implementation is nearly identical to the Bootstrap class； the differences are bolded。 Notice that instead of using the predefined Console。Out data member； the OpenStandardOutput（） method is called； and instead of File。CreateText（）； the File。Open（） method is called。 The implementation of the binary…to…text stream shell is nearly identical to the one for the text…to…binary stream shell。 You can find it in this book’s downloadable source code。 Defining the Type The central piece when converting from a text stream to a binary stream or vice versa is the definition of a type。 The type might be a class or a struct； and it is identified as being a type that can be read and written。 Identifying a type to be read and written is necessary so that when reads or writes the type； the underlying infrastructure knows what to do。 Remember that a binary data stream is a data stream where only the program knows what it means。 To help read and write those types； you add identifiers that tell what to do。 Fortunately； you don’t need to know the inner details of binary serialization； but just give an indication of how to manage it。 For the lottery…prediction example； we will define a type that represents a lottery ticket。 The lottery ticket will contain the draw date； numbers； and bonus number。 Following is the plete declaration （in the LottoLibrary project）。 …………………………………………………………Page 295…………………………………………………………… CH A PT E R 1 0 ■ L E A R N I N G A B O U T P E R S IS T E N CE 273 _ Public Class Ticket Public Sub New（） End Sub Public Sub New（ByVal drawDate As DateTime； ByVal numbers As Integer（）； _ ByVal bonus As Integer） _drawDate = drawDate _numbers = numbers _bonus = bonus End Sub Public Property Bonus（） As Integer Get Return _bonus End Get Set（ByVal value As Integer） _bonus = value End Set End Property Public Property DrawDate（） As Dat