Athena Developer Guide

Athena
Chapter 7 Accessing data Version/Issue: 2.0.0
Smart references and Smart reference vectors are declared inside a class as:
#include "GaudiKernel/SmartRef.h"
#include "GaudiKernel/SmartRefVector.h"
class MCParticle {
private:
/// Smart reference to origin vertex
SmartRef m_originMCVertex;
/// Vector of smart references to decay vertices
SmartRefVector m_decayMCVertices;
public:
/// Access the origin Vertex
/// Note: When the smart reference is converted to MCVertex* the object
/// will be loaded from the persistent medium.
MCVertex* originMCVertex() { return m_originMCVertex; }
}
The syntax of usage of smart references is identical to plain C++ pointers. The Algorithm only sees a
pointer to the MCVertex object:
#include "GaudiKernel/SmartDataPtr.h"
// Use a SmartDataPtr to get the MC particles from the event store
SmartDataPtr particles(eventSvc(),"/Event/MC/MCParticles");
MCParticleVector::const_iterator iter;
// Loop over the particles to access the MCVertex via the SmartRef
for( iter = particles->begin(); iter != particles->end(); iter++ ) {
MCVertex* originVtx = (*iter)->originMCVertex();
if( 0 != originVtx ) {
std::cout