Delphi 设计模式：《HeadFirst设计模式》Delphi7代码

1.被装饰者
{《HeadFirst设计模式》之装饰模式 }
{ 本单元中的类为被装饰者 }
{ 编译工具: Delphi7.0 }
{ E-Mail : xshlife@163.com }

unit uComponent;

interface

type
TBeverage = class(TObject) //抽象饮料类
protected
FDescription: String;
public
function GetDescription: String; virtual;
function Cost: Double; virtual; abstract;
end;

TEspresso = class(TBeverage) //浓咖啡饮料类
public
constructor Create;
function Cost: Double; override;
end;

THouseBlend = class(TBeverage) //具体HouseBlend饮料类
public
constructor Create;
function Cost: Double; override;
end;

TDarkRoast = class(TBeverage) //具体DarkRoast饮料类
public
constructor Create;
function Cost: Double; override;
end;

implementation

{ TBeverage }

function TBeverage.GetDescription: String;
begin
Result := FDescription;
end;

{ TEspresso }

function TEspresso.Cost: Double;
begin
Result := 1.99;
end;

constructor TEspresso.Create;
begin
FDescription := 'Espresso';
end;

{ THouseBlend }

function THouseBlend.Cost: Double;
begin
Result := 0.89;
end;

constructor THouseBlend.Create;
begin
FDescription := 'House Blend Coffee';
end;

{ TDarkRoast }

function TDarkRoast.Cost: Double;
begin
Result := 0.99;
end;

constructor TDarkRoast.Create;
begin
FDescription := 'Dark Roast Coffee';
end;

end.

2.装饰者
{《HeadFirst设计模式》之装饰模式 }
{ 装饰者既继承又组合被装饰者。继承 }
{ 在这里的意图主要是类型匹配 —— }
{ 与被装饰者是同一类型。 }
{ 编译工具: Delphi7.0 }
{ E-Mail : xshlife@163.com }

unit uDecorator;

interface

uses
uComponent;

type
TCondimentDecorator = class(TBeverage) //抽象装饰者
end;

TMocha = class(TCondimentDecorator) //具体装饰者：Mocha
private
FBeverage: TBever