首页 > 代码库 > Delphi 设计模式：《HeadFirst设计模式》Delphi2007代码---单例模式之ChocolateBoiler[转]
Delphi 设计模式：《HeadFirst设计模式》Delphi2007代码---单例模式之ChocolateBoiler[转]
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{《HeadFirst设计模式》之单例模式 }3
{ 编译工具: Delphi2007 for win32 }4
{ E-Mail : guzh-0417@163.com }5
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unit uChocolateBoiler;7
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interface9
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type11
TChocolateBoiler = class(TObject)12
strict private13
class var14
FUniqueInstance: TChocolateBoiler;15
strict private16
FEmpty : Boolean;17
FBoiled: Boolean;18
constructor Create;19
public20
class function GetInstance: TChocolateBoiler;21
function IsEmpty : Boolean;22
function IsBoiled: Boolean;23
procedure Fill;24
procedure Drain;25
procedure Boil;26
end;27
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implementation29
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{ TChocolateBoiler }31
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procedure TChocolateBoiler.Boil;33
begin34
if (not IsEmpty) and (not IsBoiled) then35
FBoiled := True;36
end;37
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constructor TChocolateBoiler.Create;39
begin40
FEmpty := True;41
FBoiled := False;42
end;43
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procedure TChocolateBoiler.Drain;45
begin46
if (not IsEmpty) and IsBoiled then47
FEmpty := True;48
end;49
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procedure TChocolateBoiler.Fill;51
begin52
if IsEmpty then53
begin54
FEmpty := False;55
FBoiled := False;56
end;57
end;58
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class function TChocolateBoiler.GetInstance: TChocolateBoiler;60
begin61
if FUniqueInstance = nil then62
begin63
Writeln(‘Creating unique instance of Chocolate Boiler.‘);64
FUniqueInstance := TChocolateBoiler.Create;65
end;66
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Writeln(‘Returning instance of Chocolate Boiler.‘);68
Result := FUniqueInstance;69
end;70
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function TChocolateBoiler.IsBoiled: Boolean;72
begin73
Result := FBoiled;74
end;75
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function TChocolateBoiler.IsEmpty: Boolean;77
begin78
Result := FEmpty;79
end;80
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end.1
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{《HeadFirst设计模式》之单例模式 }3
{ 客户端 }4
{ 编译工具: Delphi2007 for win32 }5
{ E-Mail : guzh-0417@163.com }6
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program pChocolateBoilerController;8
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{$APPTYPE CONSOLE}10
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uses12
SysUtils,13
uChocolateBoiler in ‘uChocolateBoiler.pas‘;14
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var16
aBoiler : TChocolateBoiler;17
aBoiler2: TChocolateBoiler;18
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begin20
aBoiler := TChocolateBoiler.GetInstance;21
aBoiler.Fill;22
aBoiler.Boil;23
aBoiler.Drain;24
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{ will return the existing instance: aBoiler }26
aBoiler2 := TChocolateBoiler.GetInstance;27
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FreeAndNil(aBoiler);29
{ FreeAndNil(aBoiler2); 同一对象（aBoiler）不能释放两次。}30
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Readln;32
end.运行结果：
Delphi 设计模式：《HeadFirst设计模式》Delphi2007代码---单例模式之ChocolateBoiler[转]
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