DemoClients.cc

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#include "TROOT.h"
#include "TSystem.h"
#include "MessageService/MsgService.h"
#include "Dispatcher/DDS.h"
#include "Dispatcher/DDSClient.h"

TROOT root("DemoClient","MINOS Data Dispatcher System Demo Client");
CVSID("$Id: DemoClients.cc,v 1.4 2003/09/30 19:49:38 kasahara Exp $");

//                                                                          //
// Data Distribution System demo client.  This program uses the DDSClient   //
// class to connect to the dispatcher server.                               //
//                                                                          //
// Arguments: serverhostname = host on which dispatcher parent server       //
//                             is running.  If not specified, the default   //
//                             is to attempt to connect to a parent server  //
//                             running on the same machine as this client.  //
//                                                                          //
//                                                                          //
// This demo only illustrates the process of connecting to ddsparentserver, //
// requesting data (which spawns the ddschildserver) and sending a shutdown //
// message to the ddschildserver.  No data is received since this isn't     //
// implemented yet in the dispatcher classes.                               //

int main(int argc, char **argv) {

  MsgStream& ms = MSGSTREAM("DDS",Msg::kInfo);

  ms << "This demo will attempt to set up 11 client connections\n"
     << "with the dispatcher server.  The first 10 will succeed.  The\n"
     << "11th will be rejected with a server 'Saturated' error message.\n"
     << "(The saturation level of the server is set by the kMaxChild\n"
     << "constant in the DDSParentServer class.  It has arbitrarily\n"
     << "been set to 10 for now.)" << endl;

  const char* serverhostname;
  if (argc > 1) {
    serverhostname = argv[1];
    ms << "The user has requested that the client will attempt to connect\n"
       << "to a parent server running on host " << serverhostname 
       << ".\n" << endl;
  }
  else {
    // Determine the host name of the current machine
    serverhostname = gSystem -> HostName();
    ms << "Since the user has not specified the host of the parent server\n"          << "as an argument to this demo, the default is to assume that the\n"
       << "parent server runs on the local host " << serverhostname 
       << ".\n" << endl;
  }

  const Int_t nclient = 11;
  // Create an array of DDSClient pointers to keep track of client connections
  DDSClient* ddsclient[nclient];

  for (Int_t ic= 0; ic < nclient; ic++) {
    // Create a DDSClient object connected to the DDS server running on 
    // node kasahara.hep.umn.edu and port 9090.
    ddsclient[ic] = new DDSClient(serverhostname,9090);

    // Check validity of connected socket before using it
    if (! ddsclient[ic]->IsValid() ) {
      ms << "Error in creation of socket connected to server for client " 
         << ic + 1 << ".\n" << endl;
      delete ddsclient[ic]; ddsclient[ic] = 0;
    }
    else {
      ms << "Successfully connected to dispatcher server for client " 
         << ic + 1 << "." << endl;
      ms << ddsclient[ic] << endl;
    }
  }

  // Normally subscribe and execute entry retrieval loop here.
  ms << "The demo will now shutdown the connected clients."
     << endl; 

  for (Int_t ic = 0; ic < nclient; ic++) {
    if ( ddsclient[ic] ) {
      ms << "Sending shutdown message to server for client " << ic + 1
         << "." << endl;
      ddsclient[ic] -> Shutdown();
      delete ddsclient[ic]; ddsclient[ic] = 0;
    }
  }

  return 0;

}

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