从头学TAO编程系列 编写最简单的TAO应用程序

上一篇我们学会了如何下载、编译和安装TAO，这一节我们来编写最简单的TAO应用程序--Hello TAO!

1. 编写TAO应用程序的一般步骤

1)	定义接口，编写idl文件
2)	编写mpc文件，生成工程文件
3)	编写server端代码
4)	编写client端代码
5)	编译,调试运行，查看结果

 

2.定义接口

接口(interface)在TAO(corba)编程在非重要，它定义了客户端（主动发起请求一方）向服务端（被动等待请求）之间通讯消息格式。在本例在， 我们定义了一个名为"Hello"的接口。Hello接口中具有两个方法：

     get_string() 和

     shutdown()

TAO用接口定义语言(idl)来表示具体的接口定义。见Hello.idl文件

//@file:   Test.idl  //@author: StoneJiang<[email protected]>  //@ref :  http://www.ace-tao.org /// Put the interfaces in a module, to avoid global namespace pollution  module Test  {    /// A very simple interface    interface Hello    {      /// Return a simple string      string get_string ();     /// A method to shutdown the ORB      /**       * This method is used to simplify the test shutdown process       */      oneway void shutdown ();    };  };

 

我们将接口Hello放在 module Test中，避免全局名字污染。

3.编写mpc文件

在上一篇我们简单的讲解了mpc在编译和ACE,TAO中的应用，在本节我们进一步使用mpc工具，为我们生成项目工程文件。

见Hello.mpc

//@file:   Hello.mpc   //@author: StoneJiang<[email protected]>  // @ref :  http://www.ace-tao.org project(*idl): taoidldefaults {    idlflags += -Sp    IDL_Files {      Test.idl    }    custom_only = 1  } project(*Server): taoserver {    after += *idl    Source_Files {      Hello.cpp      server.cpp    }    Source_Files {      TestC.cpp      TestS.cpp    }    IDL_Files {    }  } project(*Client): taoclient {    after += *idl    Source_Files {      client.cpp    }    Source_Files {      TestC.cpp    }    IDL_Files {    }  }

 

Hello.mpc定义了三个项目(project),其中*作为占位符，替换文件名Hello，所以这三个项目分别为

  1) Hello_idl

  2) Hello_Server

  3) Hello_Client

 

4. 服务端代码的编写

   服务端由 Server.cpp, Hello.cpp, Hello.h组成

// $Id: server.cpp 82798 2008-09-21 10:07:12Z johnnyw $ //@file:   server.cpp   //@author: StoneJiang<[email protected]>  //@ref :  http://www.ace-tao.org #include "Hello.h"  #include "ace/Get_Opt.h"  #include "ace/OS_NS_stdio.h" const ACE_TCHAR *ior_output_file = ACE_TEXT ("test.ior"); int  parse_args (int argc, ACE_TCHAR *argv[])  {    ACE_Get_Opt get_opts (argc, argv, ACE_TEXT("o:"));    int c;   while ((c = get_opts ()) != -1)      switch (c)        {        case 'o':          ior_output_file = get_opts.opt_arg ();          break;       case '?':        default:          ACE_ERROR_RETURN ((LM_ERROR,                             "usage:  %s "                             "-o "                             "-e shutdown server"                             "/n",                             argv [0]),                            -1);        }    // Indicates sucessful parsing of the command line    return 0;  } int  ACE_TMAIN(int argc, ACE_TCHAR *argv[])  {    try      {        CORBA::ORB_var orb =          CORBA::ORB_init (argc, argv);       CORBA::Object_var poa_object =          orb->resolve_initial_references("RootPOA");       PortableServer::POA_var root_poa =          PortableServer::POA::_narrow (poa_object.in ());       if (CORBA::is_nil (root_poa.in ()))          ACE_ERROR_RETURN ((LM_ERROR,                             " (%P|%t) Panic: nil RootPOA/n"),                            1);       PortableServer::POAManager_var poa_manager = root_poa->the_POAManager ();        if (parse_args (argc, argv) != 0)          return 1;       poa_manager->activate ();       Hello *hello_impl = 0;        ACE_NEW_RETURN (hello_impl,                        Hello (orb.in ()),                        1);        PortableServer::ServantBase_var owner_transfer(hello_impl);       PortableServer::ObjectId_var id =          root_poa->activate_object (hello_impl);       CORBA::Object_var object = root_poa->id_to_reference (id.in ());       Test::Hello_var hello = Test::Hello::_narrow (object.in ());       CORBA::String_var ior = orb->object_to_string (hello.in ());       // Output the IOR to the        FILE *output_file= ACE_OS::fopen (ior_output_file, "w");        if (output_file == 0)          ACE_ERROR_RETURN ((LM_ERROR,                             "Cannot open output file for writing IOR: %s/n",                             ior_output_file),                             1);        ACE_OS::fprintf (output_file, "%s", ior.in ());        ACE_OS::fclose (output_file);       ACE_DEBUG ((LM_DEBUG, "(%P|%t) server - wait for requsting from client./n"));       orb->run ();       ACE_DEBUG ((LM_DEBUG, "(%P|%t) server - event loop finished/n"));       root_poa->destroy (1, 1);       orb->destroy ();      }    catch (const CORBA::Exception& ex)      {        ex._tao_print_exception ("Exception caught:");        return 1;      }   return 0;  }

 

//@file:   Hello.cpp   //@author: StoneJiang<[email protected]>  // @ref :  http://www.ace-tao.org #include "Hello.h" #include "ace/Log_Msg.h" Hello::Hello (CORBA::ORB_ptr orb)    : orb_ (CORBA::ORB::_duplicate (orb))  {  } char *  Hello::get_string (void)  {     ACE_DEBUG ((LM_DEBUG, "(%P|%t) server - get_string()./n"));    return CORBA::string_dup ("Hello TAO!");  } void  Hello::shutdown (void)  {       ACE_DEBUG ((LM_DEBUG, "(%P|%t) server - shutdown()./n"));    this->orb_->shutdown (0);  }

 

 

//@file:   Hello.h   //@author: StoneJiang<[email protected]>  //@ref :  http://www.ace-tao.org #ifndef HELLO_H  #define HELLO_H  #include /**/ "ace/pre.h" #include "TestS.h" /// Implement the Test::Hello interface  class Hello    : public virtual POA_Test::Hello  {  public:    /// Constructor    Hello (CORBA::ORB_ptr orb);   // = The skeleton methods    virtual char * get_string (void);   virtual void shutdown (void); private:    /// Use an ORB reference to convert strings to objects and shutdown    /// the application.    CORBA::ORB_var orb_;  }; #include /**/ "ace/post.h"  #endif /* HELLO_H */

 

 

5. 客户端代码的编写

   服务端由 client.cpp组件

// @file: client.cpp  StoneJiang<[email protected]>  // @ref :  http://www.ace-tao.org #include "TestC.h"  #include "ace/Get_Opt.h" const ACE_TCHAR *ior = ACE_TEXT ("file://test.ior");  int  end = 0; int  parse_args (int argc, ACE_TCHAR *argv[])  {      ACE_Get_Opt get_opts (argc, argv, ACE_TEXT("k: e"));    int c;   while ((c = get_opts ()) != -1)      switch (c)        {        case 'k':          ior = get_opts.opt_arg ();          break;        case 'e':            end = 1;            break;       case '?':        default:          ACE_ERROR_RETURN ((LM_ERROR,                             "usage:  %s "                             "-k "                             "/n",                             argv [0]),                            -1);        }    // Indicates sucessful parsing of the command line    return 0;  } int  ACE_TMAIN(int argc, ACE_TCHAR *argv[])  {    try      {        CORBA::ORB_var orb = CORBA::ORB_init (argc, argv);       if (parse_args (argc, argv) != 0)          return 1;       CORBA::Object_var tmp = orb->string_to_object(ior);       Test::Hello_var hello = Test::Hello::_narrow(tmp.in ());       if (CORBA::is_nil (hello.in ()))          {            ACE_ERROR_RETURN ((LM_DEBUG,                               "Nil Test::Hello reference <%s>/n",                               ior),                              1);          }       CORBA::String_var the_string = hello->get_string ();       ACE_DEBUG ((LM_DEBUG, "(%P|%t) - string returned <%C>/n",                    the_string.in ()));       if (end)        {            hello->shutdown ();        }       orb->destroy ();      }    catch (const CORBA::Exception& ex)      {        ex._tao_print_exception ("Exception caught:");        return 1;      }   return 0;  }

 

6. 编译、调试和运行

6.1 生成工程文件

    在Dos Shell中输入

  mwc.pl -type vc9

如下图:

6.2 打开工程文件

  用Visual Studio 2008打开工程文档

编译后得到 server.exe和client.exe

6.3 运行服务端

6.4 运行客户端

6.5 运行客户端，并让服务端退出

 

7. 结束

到此，我们最简单的已经运行成功。