MapMergeable.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#pragma once
 
#include <framework/pcore/Mergeable.h>
 
namespace Belle2 {
  template <class T> class MapMergeable : public Mergeable {
  public:
    MapMergeable() : m_wrapped() {  }
 
    virtual ~MapMergeable() { }
    template<class ...Args> explicit MapMergeable(Args&& ... params) : m_wrapped(std::forward<Args>(params)...) { }
 
    T& get() { return m_wrapped; }
 
    const T& get() const { return m_wrapped; }
 
    virtual void merge(const Mergeable* other)
    {
      auto* otherMergeable = static_cast<const MapMergeable*>(other);
      for (const auto& element : otherMergeable->get()) {
        auto it = m_wrapped.find(element.first);
        if (it != m_wrapped.end()) {
          it->second += element.second;
        } else {
          m_wrapped.insert(element);
        }
      }
    }
 
    virtual void clear()
    {
      m_wrapped.clear();
    }
 
  private:
    T m_wrapped;
 
    ClassDef(MapMergeable, 1); 
  };
}