>
{ ********** TApple ********** }
function TApple.Grow: string;
begin
result:=''''苹果正在生长......'''';
end;
function TApple.Harvest: string;
begin
result:=''''苹果可以收获了......'''';
end;
function TApple.Plant: string;
begin
result:=''''苹果已经种好了......'''';
end;
{ ********** TStrawberry ********** }
function TStrawberry.Grow: string;
begin
result:=''''草莓正在生长......'''';
end;
function TStrawberry.Harvest: string;
begin
result:=''''草莓可以收获了......'''';
end;
function TStrawberry.Plant: string;
begin
result:=''''草莓已经种好了......'''';
end;
{ ********** TFruitGardener ********** }
class function TFruitGardener.Factory(whichFruit:string): IFruit;
begin
//精髓就是这条语句了 result:= TApple.Create()
//不明白赶紧去复习复习什么是多态性
if(LowerCase(whichFruit)=''''apple'''')then result:=TApple.Create()
else if(LowerCase(whichFruit)=''''grape'''')then result:=TGrape.Create()
else if(LowerCase(whichFruit)=''''strawberry'''')then result:=TStrawberry.Create()
else Raise NoThisFruitException.Create(''''这种水果还没有被种植！'''');
end;
end.
窗体界面：
//MainForm.pas 窗体文件，这里说明怎样使用简单工厂
unit MainForm;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs,SimpleFactory, StdCtrls;
type
TForm1 = class(TForm)
RadioButton1: TRadioButton;
RadioButton2: TRadioButton;
RadioButton3: TRadioButton;
RadioButton4: TRadioButton;
procedure RadioButton1Click(Sender: TObject);
procedure RadioButton2Click(Sender: TObject);
procedure RadioButton3Click(Sender: TObject);
procedure RadioButton4Click(Sender: TObject);
public
procedure Produce(fruitName:string);
end;
var
Form1: TForm1;
implementation
{ ********** TForm1 ********** }
//这就是生产过程
//IFruit 类型的临时变量 f 自己知道种的是哪种水果，有趣吧
//想要什么尽管来种，果园大丰收啦！
procedure TForm1.Produce(fruitName:string);
var
f: IFruit;
begin
try
f:=TFruitGardener.Factory(fruitName);
ShowMessage(f.Plant());
ShowMessage(f.Grow());
ShowMessage(f.Harvest());
except
on e:NoThisFruitException do Messagedlg(e.Message,mtInformation,[mbOK],0);
end;
end;
{$R *.dfm}
procedure TForm1.RadioButton1Click(Sender: TObject);
begin
Produce(''''apple''''上一页 [1] [2] [3] 下一页 |
