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;