JetViewAlg.cxx

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
// JetViewAlg.cxx
 
#if !defined(XAOD_STANDALONE)
// We do not compile JetViewAlg yet in AnalysisBase : need support for ShallowCopyDecorDeps
 
#include <memory>
#include "JetRec/JetViewAlg.h"
 
//**********************************************************************
 
// Called before event loop
StatusCode JetViewAlg::initialize() {
 
  // Initialise HandleKeys so that the scheduler is aware of
  // data dependencies & products
  if(m_input.key().empty() || m_output.key().empty()) {
    ATH_MSG_ERROR("Input/output key(s) is/are blank!");
    return StatusCode::FAILURE;
  }
 
  ATH_CHECK(m_input.initialize());
  ATH_CHECK(m_output.initialize());
  ATH_CHECK(m_decorDeps.initialize(m_input, m_output) );
 
  ATH_MSG_DEBUG("Will select jets from " << m_input.key()
        << " and write them to " << m_output.key());
  ATH_MSG_DEBUG("Selection criteria are: \n"
        << "    pT > " << m_ptmin << " MeV"
        << "    |eta| < " << m_absetamax
        );
 
  return StatusCode::SUCCESS;
}
 
//**********************************************************************
 
bool JetViewAlg::selected(const xAOD::Jet& jet) const {
 
  if(jet.pt() < m_ptmin) {return false;}
  if(std::abs(jet.eta()) > m_absetamax) {return false;}
 
  return true;
}
 
//**********************************************************************
 
StatusCode JetViewAlg::execute(const EventContext& ctx) const {  
 
  SG::ReadHandle<xAOD::JetContainer> inputHandle(m_input,ctx);
 
  // Need to place jets into a CDV because we can't put const objects in a DataVector
  auto selected_jets = std::make_unique<ConstDataVector<xAOD::JetContainer> >( SG::VIEW_ELEMENTS );
  for(const xAOD::Jet* jet : *inputHandle) {
    ATH_MSG_VERBOSE("Jet " << jet->index() << std::setprecision(3)
            << " with pt " << jet->pt()
            << " eta " << jet->eta()
            );
    if( selected(*jet) ) {
      selected_jets->push_back(jet);
      ATH_MSG_VERBOSE("  Passed selection");
    } else {
      ATH_MSG_VERBOSE(" Failed selection");
    }
  }
  ATH_MSG_DEBUG("Selected " << selected_jets->size() << " from input container of size " << inputHandle->size() );
 
  // To use ShallowCopyDecorDeps, the input and output handle types have to be the same, i.e. JetContainer
  // So create a new unique_ptr here using the pointer to the CDV converted to DV
  std::unique_ptr<const xAOD::JetContainer> selected_jets_jetc(selected_jets.release()->asDataVector());
 
  // Write out JetContainer and JetAuxContainer
  SG::WriteHandle<xAOD::JetContainer> jetContHandle(m_output,ctx);
  // Can't record with const input ptr, hence put
  if( jetContHandle.put( std::move(selected_jets_jetc) ) == nullptr) {
    ATH_MSG_ERROR("Failed to record " << m_input.key() << " as const xAOD::JetContainer!");
    return StatusCode::FAILURE;
  }
  ATH_CHECK( m_decorDeps.linkDecors (m_input,ctx) );
 
  return StatusCode::SUCCESS;
}
 
//**********************************************************************
#endif