Examples of Token/Handle to get collections in CMSSW

Check collection

edm::Handle<LumiDetails> d;
              // Check that there is something
              if (!d.isValid())  return;
              //use d

From 2016, CMSSW 7.6 ??, new way of getting collections , with Tokens

In class definition i have the following:

    edm::EDGetTokenT<EBRecHitCollection> tok_EB_;
    edm::EDGetTokenT<EERecHitCollection> tok_EE_;

    edm::EDGetTokenT<EBDigiCollection> tok_EB_digi;

In class constructor where we have access to "config"

    tok_EB_    =
    tok_EE_    =

    tok_EB_digi = consumes<EBDigiCollection>(edm::InputTag("selectDigi",

And then in analysis part I have the following:

     edm::Handle<EBRecHitCollection> EBRecHits;
     edm::Handle<EERecHitCollection> EERecHits;

    iEvent.getByToken( tok_EB_, EBRecHits );
    iEvent.getByToken( tok_EE_, EERecHits );
And then perform usual manipulations with CMSSW collections.

Old Handle notes

Use the Reco Data Format Table to get the Handle and Tags.
  • Find the header needed for the data format by clicking on the entry in the 'Containers' column.
  • Add the correxponding entry into the BuildFile (see WorkBookBuildFilesIntro ).
  • 'Handle' needs the name listed in the containers column.
  • getByLabel needs the text from the InputTag/Module(instance, if present), column.
  • The InputTag gives the name of the corresponding Process which is needed for the config file (see WriteFrameworkModule).

14 Feb 2011

More notes on collections.
What Handle getByLabel Comment
Handle<EcalRawDataCollection> DCCHeaders;
iEvent.getByLabel("ecalEBunpacker", DCCHeaders)
EE digis
edm::Handle<EEDigiCollection>  ee_digis;
iEvent.getByLabel(ecalEBunpacker,eeDigis, ee_digis);
ee_digis is a smart pointer
EB digis
edm::Handle<EBDigiCollection>  eb_digis;
iEvent.getByLabel(ecalEBunpacker,ebDigis, eb_digis);
eb_digis is a smart pointer
Handle<EcalRecHitCollection> rechits;
e.getByLabel(EcalRecHitCollection_, rechits);
where EcalRecHitCollection_ = ps.getParameter<InputTag>("EcalRecHitCollection"); in the analysis
with private attribute, parameter declaration: Input Tag EcalRecHitCollection_
and where EcalRecHitCollection = cms.InputTag("ecalRecHit","EcalRecHitsEE") in the config file
Basic ECAL clusters
edm::Handle<BasicClusterCollection> clustersH;
evt.getByLabel(ebBasicClusterTags_[i], clustersH);
Basic ECAL clusters
edm::Handle<reco::BasicClusterCollection> bccHandle;
iEvent.getByLabel(barrelClusterProducer_, barrelClusterCollection_, bccHandle);
Haupt, 29.4.2008
Track collection
edm::Handle<TrackCollection> tracksH;
evt.getByLabel(trackCollectionTag_, tracksH);

Cluster collection

James Jackson, 4Dec2009
Things start here for the instantiation of tags !!!!!!!!!!!!!
// ClusterAnalysis::ClusterAnalysis
// Instantiates the analysis, calls user methods as required
ClusterAnalysis::ClusterAnalysis(const edm::ParameterSet &ps)
   // Load track and RecHit input tags
   trackCollectionTag_ = ps.getParameter<edm::InputTag>("Tracks");   <=used in evt.getBylabel(trackCollectionTag_,tracksH); below
   loadTracks_ = ps.getParameter<bool>("LoadTracks");   <=checks for loaded track collection, below 
   ebRecHitsTag_ = ps.getParameter<edm::InputTag>("EBRecHits");   <=used by  evt.getByLabel(ebRecHitsTag_, ebRecHitsH_); below
   eeRecHitsTag_ = ps.getParameter<edm::InputTag>("EERecHits");   <=used by  evt.getByLabel(eeRecHitsTag_, eeRecHitsH_); below
   // Load barrel cluster input tags
   std::vector<std::string> ebBct = ps.getParameter<std::vector<std::string> >("EBBasicClusters");
   for(std::vector<std::string>::const_iterator it = ebBct.begin(); it != ebBct.end(); ++it)
   std::vector<std::string> ebSct = ps.getParameter<std::vector<std::string> >("EBSuperClusters");
   for(std::vector<std::string>::const_iterator it = ebSct.begin(); it != ebSct.end(); ++it)
NOTE  NOTE end of instantiation section
..............several lines of histo code..............

// ClusterAnalysis::analyze
// Analysis method called for each event
void ClusterAnalysis::analyze(const edm::Event &evt, const edm::EventSetup &es)
   // Get the track collection
   edm::Handle<TrackCollection> tracksH;
      evt.getByLabel(trackCollectionTag_, tracksH);

   // Get the RecHits
   evt.getByLabel(ebRecHitsTag_, ebRecHitsH_);
   evt.getByLabel(eeRecHitsTag_, eeRecHitsH_);
   ebRecHits_ = ebRecHitsH_.product();
   eeRecHits_ = eeRecHitsH_.product();
   // Get the geometry / topology

   // Barrel BasicClusters
   for(unsigned int i = 0; i < ebBasicClusterTags_.size(); ++i)
edm::Handle<BasicClusterCollection> clustersH;
      evt.getByLabel(ebBasicClusterTags_[i], clustersH);
     DoBasicClusterAnalysisEB(*clustersH, *tracksH, evt, ebBasicClusterHists1D_[i], ebBasicClusterHists2D_[i]);
   // Endcap BasicClusters
   for(unsigned int i = 0; i < eeBasicClusterTags_.size(); ++i)
      edm::Handle<BasicClusterCollection> clustersH;
      evt.getByLabel(eeBasicClusterTags_[i], clustersH);
      DoBasicClusterAnalysisEE(*clustersH, *tracksH, evt, eeBasicClusterHists1D_[i], eeBasicClusterHists2D_[i]);
   // Barrel SuperClusters
   for(unsigned int i = 0; i < ebSuperClusterTags_.size(); ++i)
      edm::Handle<SuperClusterCollection> clustersH;
      evt.getByLabel(ebSuperClusterTags_[i], clustersH);
      DoSuperClusterAnalysisEB(*clustersH, *tracksH, evt, ebSuperClusterHists1D_[i], ebSuperClusterHists2D_[i]);
   // Endcap SuperClusters
   for(unsigned int i = 0; i < eeSuperClusterTags_.size(); ++i)
      edm::Handle<SuperClusterCollection> clustersH;
      evt.getByLabel(eeSuperClusterTags_[i], clustersH);
      DoSuperClusterAnalysisEE(*clustersH, *tracksH, evt, eeSuperClusterHists1D_[i], eeSuperClusterHists2D_[i]);
// ClusterAnalysis::endJob


Handle with EE digis - from Sasha Ledovskoy Notes: search for 'digiProducer_' with LXR successful

Found on line 105 of


105   std::string digiProducer_; // name of module/plugin/producer making digis
106   std::string ebdigiCollection_; // secondary name given to collection of input digis
107 std::string eedigiCollection_; // secondary name given to collection of input digis

Great ! Now have correlations to the Handle
Along with:

108 std::string ebSRPdigiCollection_; // secondary name given to collection of suppressed digis
109   std::string eeSRPdigiCollection_; // secondary name given to collection of suppressed digis
110   std::string ebSrFlagCollection_; // secondary name given to collection of SR flag digis
111   std::string eeSrFlagCollection_; // secondary name given to collection of SR flag digis
112   std::string trigPrimProducer_; // name of module/plugin/producer making triggere primitives
113   std::string trigPrimCollection_; // name of module/plugin/producer making triggere primitives

string digiProducer_ = "ecalEBunpacker";
string eeDigiCollection_ = "eeDigis";
edm::Handle<EEDigiCollection>  ee_digis;   <= preapare a collection which I call "ee_digis", of type "EEDigiCollection"
iEvent.getByLabel(digiProducer_,eeDigiCollection_, ee_digis);
.....is effectively....
iEvent.getByLabel(ecalEBunpacker,eeDigis, ee_digis); 
=> which asks "ecalEBunpacker" to unpack 
=> the "eeDigis" collection and put it into ee_digis
   if ( ee_digis->size() == 0 ){
     edm::LogError("My Code: ") << "EE Digis were not found!";}
   for ( EEDigiCollection::const_iterator digiItr= ee_digis->begin();
                digiItr != ee_digis->end(); 
                               ++digiItr ) {    //1           
     EEDetId detId = EEDetId((*digiItr).id());
     // look if there is a digi record at jx,jy,jz
     int jx = EEDetId((*digiItr).id()).ix();
     int jy = EEDetId((*digiItr).id()).iy();
     int jz = EEDetId((*digiItr).id()).zside();
   //Get the 10 time samples for the digi record at jx,jy,jz for jx=49, jy=87, jz=-1
     int gain[10];
     int adc[10];
    for ( unsigned int i=0; i< (*digiItr).size() ; ++i ) { //2
       EEDataFrame df( *digiItr );
       gain[i] = df.sample(i).gainId();
       adc[i]  = df.sample(i).adc();

ECAL Rechit collection - Sam's different method

  const EcalRecHitCollection& eeHits = *heepEvt_.eeHitsFull();
  for(size_t hitNr=0;hitNr<eeHits.size();hitNr++){
    const EcalRecHit& hit = eeHits[hitNr];   <= get 'hit' here. Energy = hit.energy()
    //    std::cout <<"hit energy etc"<<hit.energy(); //<<std::endl;
    int detId = hit.id().rawId();  <= detId declared and initialised here
    float eta = GeomFuncs::getCellPos(detId).Eta(); <= eta here
    float phi = GeomFuncs::getCellPos(detId).Phi();  <= phi here
    int hits = eeHits.size(); <= number of rechits here
    EEDetId eeDetId(detId);
    int ix = eeDetId.ix();
    int iy = eeDetId.iy();
//    std::cout << "total hits, counter hitNr, ix, iy, eta, phi, hit energy " <<std::endl;
//    std::cout << hits << " " <<  hitNr << " " << ix << " " << iy << 
                                    " " << eta << " " << phi << " " << hit.energy() << std::endl;  
//    if (( gain[i] == 1 ) && (jz == 1) ) { 
    h001->Fill(ix,iy); h002->Fill(ix,iy,hit.energy()); 

-- DavidCockerill - 20-Aug-2010

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Topic revision: r10 - 2016-08-18 - DavidCockerill
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