开发学院软件开发 Delphi DesignPattern之SimpleFactory 阅读

DesignPattern之SimpleFactory

　2006-02-04 14:01:08　来源：WEB开发网　闂侀潧妫撮幏锟�

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核心提示： unit Unit2;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Controls, Dialogs, ExtCtrls, ShellAPI, AppEvnts, Forms;type IFruitInterface = inter

unit Unit2;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Controls,
Dialogs, ExtCtrls, ShellAPI, AppEvnts, Forms;
type
IFruitInterface = interface
　 ['{D4557157-5241-4116-AA1E-87F86A884EA9}']
　 PRocedure grow();
　 procedure harvest();
　 procedure plant();
end;

type
TApple = class(TComponent, IFruitInterface)
private
　 treeAge: Integer;
public
　 procedure grow();
　 procedure harvest();
　 procedure plant();
end;

TStrwaBerry = class(TComponent, IFruitInterface)
private
　 treeAge: Integer;
public
　 procedure grow();
　 procedure harvest();
　 procedure plant();
end;
TGrape = class(TComponent, IFruitInterface)
private
　 treeAge: Integer;
public
　 procedure grow();
　 procedure harvest();
　 procedure plant();
end;

TFruitGarden = class
public
　 class function GetFruit(const strFruit: string): IFruitInterface;
end;

implementation
//{$R *.dfm}
procedure TApple.grow();
begin
showmessage('Apple grow');
end;

procedure TApple.harvest();
begin
showmessage('Apple harvest');
end;

procedure TApple.plant();
begin
showmessage('Apple plant');
end;

procedure TStrwaBerry.grow();
begin
showmessage('StrwaBerry plant');
end;

procedure TStrwaBerry.harvest();
begin
showmessage('StrwaBerry plant');
end;

procedure TStrwaBerry.plant();
begin
showmessage('StrwaBerry plant');
end;

procedure TGrape.grow();
begin
showmessage('Grape plant');
end;

procedure TGrape.harvest();
begin
showmessage('Grape plant');
end;

procedure TGrape.plant();
begin
showmessage('Grape plant');
end;

class function TFruitGarden.GetFruit(const strFruit: string): IFruitInterface;
begin
if strFruit = 'Apple' then
　 Result := TApple.create(nil)
else if strFruit = 'StrawBerry' then
　 Result := TStrwaBerry.create(nil)
else if strFruit = 'Grape' then
　 Result := TGrape.create(nil)
else
　 raise Exception.Create('Cannot create ' + strFruit);
end;

end.

//test

AFruitGarden: TFruitGarden;
AFruit: IFruitInterface;
begin

AFruitGarden := TFruitGarden.Create();
try
　 AFruit := AFruitGarden.GetFruit(Edit1.Text);
　 AFruit.grow();
except on FruitError: Exception do
　　 ShowMessage(FruitError.Message);
end;

FreeAndNil(AFruitGarden);
end;