xAODDirectPhotonFilter use ReadHandleKey

Generators/GeneratorFilters/GeneratorFilters/xAODDirectPhotonFilter.h

@@ -24,6 +24,7 @@ public:
 
 private:
 
+  SG::ReadHandleKey<xAOD::TruthParticleContainer> m_truthPartContKey{this, "TruthParticleContainerKey", "TruthGen"};
   DoubleArrayProperty m_Ptmin{this, "Ptmin", {10000.}};
   DoubleArrayProperty m_Ptmax{this, "Ptmax", {std::numeric_limits<double>::max()}};
   DoubleProperty m_EtaRange{this, "Etacut", 2.50};

Generators/GeneratorFilters/src/xAODDirectPhotonFilter.cxx

@@ -13,6 +13,7 @@ xAODDirectPhotonFilter::xAODDirectPhotonFilter(const std::string& name, ISvcLoca
 
 StatusCode xAODDirectPhotonFilter::filterInitialize() {
 
+  ATH_CHECK(m_truthPartContKey.initialize());
 
   ATH_MSG_INFO("Initialising DirectPhoton filter with OrderPhotons="<<m_OrderPhotons);
 
@@ -52,19 +53,16 @@ StatusCode xAODDirectPhotonFilter::filterEvent() {
   std::vector<const xAOD::TruthParticle*> promptPhotonsInEta;
 
   int phot = 0;
-// Retrieve TruthGen container from xAOD Gen slimmer, contains all particles witout barcode_zero and
-// duplicated barcode ones
-  const xAOD::TruthParticleContainer* xTruthParticleContainer;
-  if (evtStore()->retrieve(xTruthParticleContainer, "TruthGen").isFailure()) {
-      ATH_MSG_ERROR("No TruthParticle collection with name " << "TruthGen" << " found in StoreGate!");
-      return StatusCode::FAILURE;
+  // Retrieve TruthGen container from xAOD Gen slimmer, contains all particles witout barcode_zero and
+  // duplicated barcode ones
+  SG::ReadHandle<xAOD::TruthParticleContainer> xTruthParticleContainer{m_truthPartContKey};
+  if (!xTruthParticleContainer.isValid()) {
+    ATH_MSG_ERROR("No TruthParticle collection with name " << m_truthPartContKey.key() << " found in StoreGate!");
+    return StatusCode::FAILURE;
   }
 
- // Loop over all particles in the event and find photons in given eta range
-  unsigned int nPart = xTruthParticleContainer->size();
-  for (unsigned int iPart = 0; iPart < nPart; ++iPart) {
-      const xAOD::TruthParticle* pitr =  (*xTruthParticleContainer)[iPart];
-
+  // Loop over all particles in the event and find photons in given eta range
+  for (const xAOD::TruthParticle* pitr : *xTruthParticleContainer) {
       if (MC::isPhoton(pitr) &&
           MC::isStable(pitr) &&
           std::abs(pitr->eta()) <= m_EtaRange) {