(NET) NET (2016)

Builder in VB.NET

Separates object construction from its representation

Separate the construction of a complex object from its representation so that the same construction process can create different representations. The construction process can create different object representations and provides a high level of control over the assembly of the objects.

Please download project with this source code from https://github.com/ViacheslavUKR/StandardDisignOopPattern

   1:      ' Builder Design Pattern.

   2:      ' See description in //www.vb-net.com/ProgramTheory/Builder.htm

   3:      Public Class MainApp

   4:          ' Entry point into console application.

   5:          Public Shared Sub Main()

   6:              ' Create director and builders

   7:              Dim director As New Director()

   8:              Dim b1 As Builder = New ConcreteBuilder1()

   9:              Dim b2 As Builder = New ConcreteBuilder2()

  10:              ' Construct two products

  11:              director.Construct(b1)

  12:              Dim p1 As Product = b1.GetResult()

  13:              p1.Show()

  14:              director.Construct(b2)

  15:              Dim p2 As Product = b2.GetResult()

  16:              p2.Show()

  17:              ' Wait for user

  18:              Console.ReadKey()

  19:          End Sub

  20:      End Class

21:

  22:      ' The 'Director' class

  23:      Class Director

  24:          ' Builder uses a complex series of steps

  25:          Public Sub Construct(builder As Builder)

  26:              builder.BuildPartA()

  27:              builder.BuildPartB()

  28:          End Sub

  29:      End Class

30:

  31:      ' The 'Builder' abstract class

  32:      MustInherit Class Builder

  33:          Public MustOverride Sub BuildPartA()

  34:          Public MustOverride Sub BuildPartB()

  35:          Public MustOverride Function GetResult() As Product

  36:      End Class

37:

  38:      ' The 'ConcreteBuilder1' class

  39:      Class ConcreteBuilder1

  40:          Inherits Builder

  41:          Private _product As New Product()

  42:          Public Overrides Sub BuildPartA()

  43:              _product.Add("PartA")

  44:          End Sub

  45:          Public Overrides Sub BuildPartB()

  46:              _product.Add("PartB")

  47:          End Sub

  48:          Public Overrides Function GetResult() As Product

  49:              Return _product

  50:          End Function

  51:      End Class

52:

  53:      ' The 'ConcreteBuilder2' class

  54:      Class ConcreteBuilder2

  55:          Inherits Builder

  56:          Private _product As New Product()

  57:          Public Overrides Sub BuildPartA()

  58:              _product.Add("PartX")

  59:          End Sub

  60:          Public Overrides Sub BuildPartB()

  61:              _product.Add("PartY")

  62:          End Sub

  63:          Public Overrides Function GetResult() As Product

  64:              Return _product

  65:          End Function

  66:      End Class

67:

  68:      ' The 'Product' class

  69:      Class Product

  70:          Private _parts As New List(Of String)()

  71:          Public Sub Add(part As String)

  72:              _parts.Add(part)

  73:          End Sub

  74:          Public Sub Show()

  75:              Console.WriteLine(vbLf & "Product Parts -------")

  76:              For Each part As String In _parts

  77:                  Console.WriteLine(part)

  78:              Next

  79:          End Sub

  80:      End Class

See also:

Creational Patterns

Abstract Factory in VB.NET - Creates an instance of several families of classes.
Builder in VB.NET - Separates object construction from its representation.
Factory Method in VB.NET - Creates an instance of several derived classes.
Prototype in VB.NET - A fully initialized instance to be copied or cloned.
Singleton in VB.NET - A class of which only a single instance can exist.

Structural Patterns

Adapter in VB.NET - Match interfaces of different classes
Bridge in VB.NET - Separates an object???s interface from its implementation
Composite in VB.NET - A tree structure of simple and composite objects
Decorator in VB.NET - Add responsibilities to objects dynamically
Facade in VB.NET - A single class that represents an entire subsystem
Flyweight in VB.NET - A fine-grained instance used for efficient sharing
Proxy in VB.NET - An object representing another object

Behavioral Patterns

Chain of Resp. in VB.NET - A way of passing a request between a chain of objects
Command in VB.NET - Encapsulate a command request as an object
Interpreter in VB.NET - A way to include language elements in a program
Iterator in VB.NET - Sequentially access the elements of a collection
Mediator in VB.NET - Defines simplified communication between classes
Memento in VB.NET - Capture and restore an object's internal state
Observer in VB.NET - A way of notifying change to a number of classes
State in VB.NET - Alter an object's behavior when its state changes
Strategy in VB.NET - Encapsulates an algorithm inside a class
Template Method in VB.NET - Defer the exact steps of an algorithm to a subclass
Visitor in VB.NET - Defines a new operation to a class without change

Theory context:

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