Delphi 设计模式：《HeadFirst设计模式》Delphi7代码---命令模式之SimpleRemoteControlTest

1. 命令的接受者

unit uReceiveObject;interfacetype TLight = class(TObject) public procedure Open; procedure Off; end; TGarageDoor = class(TObject) public procedure Up; procedure Down; procedure Stop; procedure LightOn; procedure LightOff; end;implementation{ TLight }procedure TLight.Off;begin Writeln('');end;procedure TLight.Open;begin Writeln('Light is On.');end;{ TGarageDoor }procedure TGarageDoor.Down;begin Writeln('');end;procedure TGarageDoor.LightOff;begin Writeln('');end;procedure TGarageDoor.LightOn;begin Writeln('');end;procedure TGarageDoor.Stop;begin Writeln('');end;procedure TGarageDoor.Up;begin Writeln('GarageDoor is Open.');end;end.

 

2.命令对象

unit uCommandObject;interfaceuses uReceiveObject;type TCommand = class(TObject) public procedure Execute; virtual; abstract; end; TLightOnCommand = class(TCommand) private FLight: TLight; public constructor Create(aLight: TLight); procedure Execute; override; end; TGarageDoorOpenCommand = class(Tcommand) private FGarageDoor: TGarageDoor; public constructor Create(aGarageDoor: TGarageDoor); procedure Execute; override; end;implementation{ TLightOnCommand }constructor TLightOnCommand.Create(aLight: TLight);begin FLight := aLight;end;procedure TLightOnCommand.Execute;begin FLight.Open;end;{ TGarageDoorOpenCommand }constructor TGarageDoorOpenCommand.Create(aGarageDoor: TGarageDoor);begin FGarageDoor := aGarageDoor;end;procedure TGarageDoorOpenCommand.Execute;begin FGarageDoor.Up;end;end.

 

3.命令的请求者即发出者

unit uSimpleRemoteControl;interfaceuses uCommandObject;type TSimpleRemoteControl = class(TObject) private FSlot: TCommand; public procedure SetCommand(aCommand: TCommand); procedure ButtonWasPressed; end;implementation{ TSimpleRemoteControl }procedure TSimpleRemoteControl.ButtonWasPressed;begin FSlot.Execute;end;procedure TSimpleRemoteControl.SetCommand(aCommand: TCommand);begin FSlot := aCommand;end;end.

 

4.客户端代码

program pSimpleRemoteControlTest;{$APPTYPE CONSOLE}uses uSimpleRemoteControl in 'uSimpleRemoteControl.pas', uCommandObject in 'uCommandObject.pas', uReceiveObject in 'uReceiveObject.pas';var Remote: TSimpleRemoteControl; Light: TLight; GarageDoor: TGarageDoor; LightOnCommand: TCommand; GarageDoorOpenCommand: TCommand; begin {创建命令的发出者} Remote := TSimpleRemoteControl.Create; {创建命令的接收者} Light := TLight.Create; GarageDoor := TGarageDoor.Create; {创建具体的命令对象} LightOnCommand := TLightOnCommand.Create(Light); GarageDoorOpenCommand := TGarageDoorOpenCommand.Create(GarageDoor); {加载命令并执行} Remote.SetCommand(LightOnCommand); Remote.ButtonWasPressed; Remote.SetCommand(GarageDoorOpenCommand); Remote.ButtonWasPressed; Remote.Free; Light.Free; GarageDoor.Free; LightOnCommand.Free; GarageDoorOpenCommand.Free; Readln;end.

 

运行结果: