工厂模式（FactoryMethod）

unit uFactoryMethod;

interface

uses Classes,Windows,Messages,Dialogs;

type
TMobile = class
public
procedure Call();virtual;abstract;
end;
TNokia = class(TMobile)
public
constructor Create();
procedure Call();override;
end;
TMotorola = class(TMobile)
public
constructor Create;
procedure Call();override;
end;
TMobileFactory = class
public
function produceMobile():TMobile;virtual; abstract;
end;
TMotorolaFactory = class(TMobileFactory)
public
function produceMobile():TMobile;override;
end;
TNokiaFactory = class(TMobileFactory)
private
public
function produceMobile():TMobile;override;
end;

implementation

{ TNokia }

procedure TNokia.Call;
begin
inherited;
ShowMessage('a call of Nokia');
end;

constructor TNokia.Create;
begin

end;

{ TMotorola }

procedure TMotorola.Call;
begin
inherited;
ShowMessage('a call of motorola');
end;

constructor TMotorola.Create;
begin

end;

{ TMotorolaFactory }

function TMotorolaFactory.produceMobile: TMobile;
var
Motorola:TMotorola;
begin
Motorola:=TMotorola.Create;
Result:=Motorola;

end;

{ TNokiaFactory }
function TNokiaFactory.produceMobile: TMobile;
var
Nokia:TNokia;
begin
Nokia:=TNokia.Create;
Result:=Nokia;
end;

end.
//=============================================================================
//测试工厂模式
//============================================================================

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation
uses uFactoryMethod;
{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
mbf:TMobileFactory;
mb:TMobile;
begin
mbf:=TMotorolaFactory.Create;
mb:=mbf.produceMobile;
mb.Call;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
mbf:TMobileFactory;
mb:TMobile;
begin
mbf:=TNokiaFactory.Create;
mb:=mbf.produceMobile;
mb.Call;
end;

end.