3D PLM Enterprise Architecture

Choosing the Interface Name

You can add to this four-character prefix the trigram of the framework into which you intend to put the interface, providing you manage a list of unique trigrams for your frameworks [2]. This lets you manage unique interface names at the framework level. For example, sample interfaces of the CAASystem.edu framework, that illustrates the CATIA System framework, begin with CAAISys, where Sys is the trigram for the System framework.

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Creating the Interface Header File

Create the interface header file, such as CAAISysPoint.h. Since an interface is usually intended for clients, this header file should be placed in the PublicInterfaces directory of your framework. Insert in this file:

• The preprocessor directives that enclose the header file contents

  #ifndef CAAISysCollection_h
  #define CAAISysCollection_h
  ...
  #endif

  These directives protect from file multiple inclusion

• The include statement to the base interface header file, and to header files of interfaces used as parameter types for the interface methods. There are none in this example.

...
#include "CATBaseUnknown.h"
...

• The framework header file that contains the framework export information

  ...
  #include "CAASysGeoModelInf.h"
  ...

• The IID declaration

...
extern ExportedByCAASysGeoModelInf IID IID_CAAISysCollection;
...

• The class declaration and the inherited class

...
class ExportedByCAASysGeoModelInf CAAISysCollection : public CATBaseUnknown
{
...

• The CATDeclareClass macro, always located before the public keyword

...
CATDeclareClass;
...

• The methods, always declared as public and pure virtual, and returning a HRESULT [3]

  ...
  public :
    virtual HRESULT GetNumberOfObjects(int * oCount) = 0;
    virtual HRESULT GetObject    (int iRank,
                                  CATBaseUnknown ** oObject) = 0;
    virtual HRESULT AddObject    (CATBaseUnknown *  iObject) = 0;
    virtual HRESULT RemoveObject (CATBaseUnknown *  iObject) = 0;
    virtual HRESULT Empty() = 0;
  };
  ...

The header file is:

#ifndef CAAISysCollection_h
#define CAAISysCollection_h

#include "CATBaseUnknown.h"

#include "CAASysGeoModelInf.h"

extern ExportedByCAASysGeoModelInf IID IID_CAAISysCollection;

class ExportedByCAASysGeoModelInf CAAISysCollection : public CATBaseUnknown
{
  CATDeclareInterface;
  public:
    virtual HRESULT GetNumberOfObjects(int * oCount) = 0;
    virtual HRESULT GetObject    (int iRank,
                                  CATBaseUnknown ** oObject) = 0;
    virtual HRESULT AddObject    (CATBaseUnknown * iObject) = 0;
    virtual HRESULT RemoveObject (CATBaseUnknown * iObject) = 0;
    virtual HRESULT Empty  () =0 ;
};
#endif

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Creating the Interface Source File

Create the interface source file in the src directory of the module dedicated to interfaces of your framework, such as CAAISysCircle.cpp file, and insert in it:

• The include statement to the class header file

  #include "CAAISysCollection.h"
  ...

• The IID [4] initialization

  ...
  IID IID_CAAISysCollection = { /* 8d143952-d4bf-11d3-b7f5-0008c74fe8dd */
      0x8d143952,
      0xd4bf,
      0x11d3,
      {0xb7, 0xf5, 0x00, 0x08, 0xc7, 0x4f, 0xe8, 0xdd}
    };
  ...

• The CATImplementInterface macro to make a CAA V5 interface from this abstract class. The parameters of CATImplementInterface are the interface name and the base interface name respectively

  ...
  CATImplementInterface(CAAISysCollection, CATBaseUnknown);

The source file is:

#include "CAAISysCollection.h"

IID IID_CAAISysCollection = { /* 8d143952-d4bf-11d3-b7f5-0008c74fe8dd */
    0x8d143952,
    0xd4bf,
    0x11d3,
    {0xb7, 0xf5, 0x00, 0x08, 0xc7, 0x4f, 0xe8, 0xdd}
  };

CATImplementInterface(CAAISysCollection, CATBaseUnknown);

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Creating the TIE File

Create the TIE file in the src directory of the module dedicated to interfaces of your framework, such as TIE_CAAISysCollection.tsrc, to request the code builder mkmk to generate the TIE associated with the interface. Because your clients do not need the TIE to retrieve a pointer to your interface thanks to QueryInterface and to call its methods, the TIE is created in the ProtectedGenerated directory by default.

#include "CAAISysCollection.h"

If the client must implement the interface, create the TIE in the PublicGenerated directory. The TIE file should then also include the //public keyword.

#include "CAAISysCollection.h"
//public

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In Short

Creating interfaces implies choosing a name appropriate for both interface easy identification and interface name uniqueness. Then you can create the interface header and source files. Last, the interface TIE file lets mkmk automatically create the interface TIE.

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References

History

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