Delphi设计模式：《HeadFirst设计模式》Delphi代码---模式小结之加入适配器模式 ...

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二、加入适配器模式

1、鹅也要加入鸭鸣模拟器

代码


 1 {《HeadFirst设计模式》Delphi代码之模式小结 }
 2 { 加入适配器模式                             }
 3 { 编译工具：Delphi2010 for win32         }
 4 { E-Mail  ：[email protected]           }
 5  
 6  unit uGoose;
 7 
 8  interface
 9 
10  type
11   TGoose = class(TObject)
12   public
13     procedure Honk;
14   end;
15 
16  implementation
17 
18  { TGoose }
19 
20  procedure TGoose.Honk;
21  begin
22   Writeln('Honk');
23  end;
24 
25  end.

2、但鹅的叫声接口与鸭子的不一致，鹅变量的类型与procedure Simulate(aDuck: IQuackable)要求的不一致。加入适配器转换鹅的接口，同时也保持了procedure Simulate(aDuck: IQuackable)对多态的要求。

代码


 1 {《HeadFirst设计模式》Delphi代码之模式小结 }
 2 { 加入适配器模式                             }
 3 { 编译工具：Delphi2010 for win32         }
 4 { E-Mail  ：[email protected]           }
 5 
 6  unit uGooseAdapter;
 7 
 8  interface
 9 
10  uses
11   uQuackable, uGoose;
12 
13 type
14   TGooseAdapter = class(TInterfacedObject, IQuackable)
15   private
16     FGoose: TGoose;
17   public
18     constructor Create(aGoose: TGoose);
19     destructor Destroy; override;
20     procedure Quack;
21   end;
22 
23 implementation
24 
25 { TGooseAdapter }
26 
27 constructor TGooseAdapter.Create(aGoose: TGoose);
28 begin
29   FGoose := aGoose;
30 end;
31 
32 destructor TGooseAdapter.Destroy;
33 begin
34   FGoose.Free;
35   inherited Destroy;
36 end;
37 
38 procedure TGooseAdapter.Quack;
39 begin
40   FGoose.Honk;
41 end;
42 
43 end.

3、最后测试一下

代码


 1 {《HeadFirst设计模式》Delphi代码之模式小结 }
 2 { 测试                                       }
 3 { 编译工具：Delphi2010 for win32         }
 4 { E-Mail  ：[email protected]           }
 5 
 6 unit uDuckSimulator;
 7 
 8 interface
 9 
10 uses
11   uQuackable, uDuck, uGoose, uGooseAdapter;
12 
13 type
14   TDuckSimulator = class(TObject)
15   private
16     procedure Simulate(aDuck: IQuackable); overload;
17   public
18     procedure Simulate; overload;
19   end;
20 
21 implementation
22 
23 { TDuckSimulator }
24 
25 procedure TDuckSimulator.Simulate(aDuck: IQuackable);
26 begin
27   aDuck.Quack;
28 end;
29 
30 procedure TDuckSimulator.Simulate;
31 var
32   aMallardDuck: IQuackable;
33   aRedHeadDuck: IQuackable;
34   aDuckCall   : IQuackable;
35   aRubberDuck : IQuackable;
36   aGooseDuck  : IQuackable;
37 begin
38   try
39     aMallardDuck := TMallardDuck.Create;
40     aRedHeadDuck := TRedHeadDuck.Create;
41     aDuckCall    := TDuckCall.Create;
42     aRubberDuck  := TRubberDuck.Create;
43     aGooseDuck   := TGooseAdapter.Create(TGoose.Create);
44 
45     Writeln('Duck Simulator: With Goose Adapter');
46 
47     Simulate(aMallardDuck);
48     Simulate(aRedHeadDuck);
49     Simulate(aDuckCall);
50     Simulate(aRubberDuck);
51     Simulate(aGooseDuck );
52   finally
53     aMallardDuck := nil;
54     aRedHeadDuck := nil;
55     aDuckCall    := nil;
56     aRubberDuck  := nil;
57     aGooseDuck   := nil;
58   end;
59 end;
60 
61 end.

代码


 1 {《HeadFirst设计模式》Delphi代码之模式小结 }
 2 { 客户端                                     }
 3 { 编译工具：Delphi2010 for win32         }
 4 { E-Mail  ：[email protected]           }
 5 
 6 program pDuckSimulator;
 7 
 8 {$APPTYPE CONSOLE}
 9 
10 uses
11   uQuackable in 'uQuackable.pas',
12   uDuck in 'uDuck.pas',
13   uDuckSimulator in 'uDuckSimulator.pas',
14   uGooseAdapter in 'uGooseAdapter.pas',
15   uGoose in 'uGoose.pas';
16 
17 var
18   aSimulator: TDuckSimulator;
19 
20 begin
21   aSimulator := TDuckSimulator.Create;
22 
23   aSimulator.Simulate;
24 
25   aSimulator.Free;
26 
27   Readln;
28 end.