ProofEvent.C: Example of TSelector implementation to do generic

#define ProofEvent_cxx

// Example of TSelector implementation to do generic
// processing with the test 'Event' structure.

// The following methods are defined in this file:
//    Begin():        called everytime a loop on the tree starts,
//                    a convenient place to create your histograms.
//    SlaveBegin():   called after Begin(), when on PROOF called only on the
//                    slave servers.
//    Process():      called for each event, in this function you decide what
//                    to read and fill your histograms.
//    SlaveTerminate: called at the end of the loop on the tree, when on PROOF
//                    called only on the slave servers.
//    Terminate():    called at the end of the loop on the tree,
//                    a convenient place to draw/fit your histograms.
//

#include "ProofEvent.h"
#include "Event.h"

#include <TCanvas.h>
#include <TH1F.h>
#include <TRandom3.h>

//_____________________________________________________________________________
ProofEvent::ProofEvent()
{
   // Constructor

   fEvent = 0;
   fNtrack = -1; 
   fHisto = 0;
   fRandom = 0;
}

//_____________________________________________________________________________
ProofEvent::~ProofEvent()
{
   // Destructor

   SafeDelete(fRandom);
}

//_____________________________________________________________________________
void ProofEvent::Begin(TTree * /*tree*/)
{
   // The Begin() function is called at the start of the query.
   // When running with PROOF Begin() is only called on the client.
   // The tree argument is deprecated (on PROOF 0 is passed).

   TString option = GetOption();
   Info("Begin", "starting a simple exercise with process option: %s", option.Data());
}

//_____________________________________________________________________________
void ProofEvent::SlaveBegin(TTree * /*tree*/)
{
   // The SlaveBegin() function is called after the Begin() function.
   // When running with PROOF SlaveBegin() is called on each slave server.
   // The tree argument is deprecated (on PROOF 0 is passed).

   TString option = GetOption();
   Info("SalveBegin", "starting on a slave with process option: %s", option.Data());

   // Create event
   fEvent = new Event();

   // Create the histogram
   fHisto = new TH1F("histo", "tracks multiplicity", 20, 0, 100);
   fHisto->GetYaxis()->SetTitle("number of events");
   fHisto->GetXaxis()->SetTitle("number of tracks");

   //adding histo to selector output list
   fOutput->Add(fHisto);

   // Set random seed
   fRandom = new TRandom3(0);
}

//_____________________________________________________________________________
Bool_t ProofEvent::Process(Long64_t )
{

  // Start main loop over all events
  // get a random parameter for connstructing event

   int i= (int)(100 * (fRandom->Rndm()));
   fEvent->Build(i,(1+i), 2);
   fNtrack= (fEvent->GetNtrack());
   if ((fNtrack >= 0 )&& (fNtrack <= 100 ))
      fHisto->Fill(fNtrack, 1);

   return kTRUE;
}

//_____________________________________________________________________________
void ProofEvent::SlaveTerminate()
{
   //nothing to be done

}

//_____________________________________________________________________________
void ProofEvent::Terminate()
{
   // The Terminate() function is the last function to be called during
   // a query. It always runs on the client, it can be used to present
   // the results graphically or save the results to file.

   TCanvas *c1 = new TCanvas("c1","Proof ProofEvent canvas",200,10,700,700);
   fHisto = dynamic_cast<TH1F *>(fOutput->FindObject(Form("histo")));
   if (fHisto) {
      fHisto->Draw("h");

      // Final update
      c1->cd();
      c1->Update();
   } else {
      Warning("Terminate", "histogram not found");
   }
}