Abstract products: such as abstract fruits.
Specific product: Apple, grape, etc. inherited from Fruit.
Factory: Responsible for the production of various fruits.
Unit factoryMethodunit;
interfacetype TFruitID = (Grape, Apple); TFruit = class // abstract interface public constructor Create; virtual; end; TGrape = class (Fruit) // specific class constructor Create; override; end; TApple = class (Fruit) // specific Class constructor create; override;
Tcreator = Class // Factory Public Constructor Create; Virtual; Function CreateProduct (Fruitid: TFRuitid): TFRUIT; Virtual;
TMYCREATOR = Class (TCREATOR) Constructor Create; Override; Function CreateProduct (FRUTID: TFRUTID): TFRUIT; OVERRIDE; / / END;
IMPLEMentation
function TCreator.CreateProduct (FruitID: TFruitID): TFruit; var aProduct: TFruit; begin aProduct: = nil; if FruitID = Grape then aProduct: = TGrape.Create; if FruitID = Apple then aProduct: = TApple.Create; Result: = APROD;
Constructor tgrape.create; begin // ...... End;
Constructor Tapple.create; begin // ...... end;
Constructor tcreator.create; begin // ...... End;
Constructor TMYCREATOR.CREATE; Begin // ...
Function TMYCREATOR.CREATEPRODUCT (FRUTID: TFRUTID): TFRUIT; VAR APRODUCT: TFRUIT; Acreator: Tcreator; Begin
Aproduct: = nil; if fruitid = grape dam; = tgrape.create; if Fruitid = Apple Then Aproduct: = TAPPLE.CREATE
IF APRODUCT = NIL THEN BEGIN AcReator: = Tcreator.create; Aproduct: = Acreator.createProduct (Fruit); End; Result: = APRODUCT;
End.
