End Set End Property Public Property DrawDate（） As DateTime Get Return _drawDate End Get Set（ByVal value As DateTime） _drawDate = value End Set End Property Public Property Numbers（） As Integer（） Get Return _numbers End Get Set（ByVal value As Integer（）） _numbers = value End Set End Property Private _bonus As Integer Private _drawDate As DateTime Private _numbers As Integer（） End Class Ticket is plain…vanilla data class。 However； the bolded parts deserve an explanation。 The first bolded part is a set of angled brackets surrounding the identifier Serializable； which represents a attribute。 In ； you have the ability to describe types； methods； and so on。 …………………………………………………………Page 296…………………………………………………………… 274 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 Attributes are descriptions that are used in a particular context。 As opposed to the identifiers Public and MustInherit； which are descriptions that fundamentally describe how a type will behave； the Serializable attribute describes the behavior of a type in a specific context—when the object is to be converted from memory to a data stream and vice versa。 Fundamental descrip tions are important to the runtime； whereas attributes are generally not important to the runtime； but important to libraries that the runtime will execute。 ■Note Serialization is the process of turning an object into a format that can be saved or sent over the network。 Deserialization is the process of retrieving the serialized object。 The Serializable attribute describes the ability to serialize the type as it is declared。 When Ticket is converted into a binary stream； the programmer does not need to do anything other than pass an instance to the data stream。 The data stream libraries handle all of the other details。 In the declaration of Ticket； the parameterless constructor has been bolded to emphasize that this type of constructor is necessary when converting a data stream into an object instance。 When binary streams restore types； they instantiate an empty object and then assign the data members。 Thus； when an object is created； a parameterless constructor is needed。 Converting a Text Stream into a Binary Stream To convert the stream from text to binary involves breaking apart the text stream； instantiating a Ticket instance； assigning the data members； and saving the instance to the binary stream。 All of these steps are performed in the following source code （you’ll need a reference to LottoLibrary in Text2Binary）。 Imports System。IO Imports System。Runtime。Serialization。Formatters。Binary Imports System。Text Public Class LottoTicketProcessor ： Implements IText2BinaryProcessor Public Sub Process（ByVal reader As TextReader； ByVal writer As Stream） _ Implements IText2BinaryProcessor。Process Dim retval As StringBuilder = New StringBuilder（） Do While reader。Peek（） …1 Dim lineOfText As String = reader。ReadLine（） Dim splitUpText As String（）= lineOfText。Split（New Char（） ｛〃 〃c｝） Dim dateSplit As String（） = splitUpText（0）。Split（New Char（） ｛〃。〃c｝） Dim ticket As LottoLibrary。Ticket = _ New LottoLibrary。Ticket（ _ New DateTime（ _ Integer。Parse（dateSplit（0））； _ Integer。Parse（dateSplit（1））； _ Integer。Parse（dateSplit（2）））； _ …………………………………………………………Page 297…………………………………………………………… 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 275 New Integer（） ｛ _ Integer。Parse（splitUpText（1））； _ Integer。Parse（splitUpText（2））； _ Integer。Parse（splitUpText（3））； _ Integer。Parse（splitUpText（4））； _ Integer。Parse（splitUpText（5））； _ Integer。Parse（splitUpText（6）） ｝； _ Integer。Parse（splitUpText（7））） Dim formatter As BinaryFormatter = New BinaryFormatter（） formatter。Serialize（writer； ticket） Loop End Sub End Class The code splits the text stream by reading a line of text and then splitting apart the fields。 The split…apart fields are then converted into numbers by using the Integer。Parse（） method。 This process of splitting and conversion is called marshaling data。 Marshaling is a technical term that means to convert a type from one medium to another。 We manage the text marshaling； but manages the binary marshaling； which is still there behind the scenes。 The System。Runtime。Serialization。Formatters。Binary。BinaryFormatter type manages marshaling of the Ticket instance to the binary stream。 The Serializable attribute is used by the BinaryFormatter as an indicator that the Ticket type is allowed to be serialized and deserialized。 In essence； converting from a text stream to a binary stream means to marshal a text…defined ticket into a …defined ticket； and that is then marshaled into a binary…defined ticket。 Converting a Binary Stream into a Text Stream Converting a