DBArray.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/database/DBAccessorBase.h>
 
#include <framework/utilities/ArrayIterator.h>
 
#include <TClonesArray.h>
#include <stdexcept>
 
namespace Belle2 {
  template<class T> class DBArray: public DBAccessorBase {
  public:
    typedef ObjArrayIterator<const TClonesArray, const T> const_iterator;
 
    explicit DBArray(const std::string& name = "", bool required = true):
      DBAccessorBase(DBStore::arrayName<T>(name), T::Class(), true, required) {}
 
    inline int getEntries() const { return isValid() ? getObject<TClonesArray>()->GetEntriesFast() : 0;}
 
    inline const T* operator [](int i) const
    {
      if (!isValid()) {
        throw std::out_of_range("Out-of-range access in DBArray::operator[], for " + getName() + ": Object not valid");
      }
      //At() checks for out-of-range and returns NULL in that case
      TObject* obj = getObject<TClonesArray>()->At(i);
      if (obj == nullptr)
        throw std::out_of_range("Out-of-range access in DBArray::operator[], for " + getName() + ", index " + std::to_string(i));
      return static_cast<T*>(obj); //type was checked by DataStore, so the cast is safe.
    }
 
    template<class KEY> const T* getByKey(KEY(T::*method)(void) const, KEY key) const
    {
      const TClonesArray& array = *getObject<TClonesArray>();
      for (int i = 0; i < getEntries(); i++) {
        T* obj = static_cast<T*>(array.At(i));
        if ((*obj.*method)() == key) {
          return obj;
        }
      }
      return nullptr;
    }
 
    const_iterator begin() const { return const_iterator(getObject<TClonesArray>(), false); }
    const_iterator end() const { return const_iterator(getObject<TClonesArray>(), true); }
  };
 
  template<class T> class OptionalDBArray: public DBArray<T> {
  public:
    explicit OptionalDBArray(const std::string& name = ""): DBArray<T>(name, false) {}
  };
}