JSonSupportkit.hh

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#ifndef __JDB_JSONSUPPORTKIT__
#define __JDB_JSONSUPPORTKIT__

#include <sstream>
#include <vector>
#include <typeinfo>
#include <memory>

#include "TDictionary.h"

#include "JROOT/JRootClass.hh"

#include "JLang/JException.hh"
#include "JLang/JTypeList.hh"
#include "JLang/JPrimitiveTypes.hh"
#include "JLang/JSingleton.hh"

#include "JSon/JSon.hh"

/**
 * \author mdejong
 */
namespace JDATABASE {}
namespace JPP { using namespace JDATABASE; }

namespace JDATABASE {

  using JSON::json;
  using JROOT::JRootWritableClass;
  using JROOT::JRootReadableClass;
  using JLANG::JException;
  using JLANG::JSingleton;

  /**
   * Assigment interface.
   */
  struct JSonIO {

    virtual ~JSonIO()
    {}

    virtual void to_json(json& js, const void* p) const = 0;
    virtual void from_json(const json& js, void* p) const = 0;
  };


  /**
   * Assigment implementation.
   */
  template<class T>
  struct JSonIO_t :
    public JSonIO
  {
    virtual void to_json(json& js, const void* p) const override
    { 
      js = * (const T*) p;
    }
    
    virtual void from_json(const json& js, void* p) const override
    {
      * (T*) p = js;
    }
  };


  /**
   * Assignment.
   */
  struct JSonDictionary :  
    public std::map< std::string, std::shared_ptr<JSonIO> >,
    public JSingleton<JSonDictionary>
  {
   /**
    * Default constructor.
    *
    * Removed types:
    *  - <tt>long double</tt> (not supported by ROOT TDictionary)
    *  - <tt>char</tt> (not supported by JSon)
    *
    * Added STL type definitions:
    *  - <tt>std::string</tt>
    *  - <tt>size_t</tt>
    *  - <tt>std::size_t</tt>
    */
    JSonDictionary()
    {
      using namespace JPP;

      for_each<JRemove<JPrimitiveTypes_t, JTypeList<char, long double> >::typelist>(*this);

      (*this)(JType<std::string>());
      (*this)(JType<size_t>());
      (*this)(JType<std::size_t>());
    }


    /**
     * Get typename for given template class.
     *
     * This method uses the TDictionary class to get the name of the given class.
     *
     * \return               type name
     */
    template<class T>
    static const char* getTypename()
    {
      const TDictionary* pDictionary = TDictionary::GetDictionary(typeid(T));

      if (pDictionary != NULL)
        return pDictionary->GetName();
      else
        THROW(JException, "Data type not implemented.");
    }

    /**
     * Add data type.
     *
     * \param  type            data type
     */
    template<class T>
    void operator()(const JLANG::JType<T>& type)
    {
      (*this)[getTypename<T>()] = std::make_shared< JSonIO_t<T> >();
    }
  };


  /**
   * Auxiliary base class for JSon I/O based on ROOT dictionary.
   */
  template<class T>
  struct JSonHelper {
    /**
     * Convert object to JSon.
     *
     * \param  js         json
     * \param  object     object
     */
    friend inline void to_json(json& js, const T& object)
    {
      using namespace std;
      using namespace JPP;

      JRootWritableClass cls(object);

      for (unique_ptr<TIterator> i(cls.getClass()->GetListOfDataMembers()->MakeIterator()); const TDataMember* p = (const TDataMember*) i->Next(); ) {

        if (!JRootClass::is_static(*p)) {

          JRootWritableClass abc = cls.get(*p);

          JSonDictionary::getInstance()[abc.getTypename()]->to_json(js[p->GetName()], abc.getAddress());
        }
      }
    }


    /**
     * Convert JSon to object/.
     *
     * \param  js         json
     * \param  object     object
     */
    friend inline void from_json(const json& js, T& object)
    {
      using namespace std;
      using namespace JPP;

      JRootReadableClass cls(object);

      for (unique_ptr<TIterator> i(cls.getClass()->GetListOfDataMembers()->MakeIterator()); const TDataMember* p = (const TDataMember*) i->Next(); ) {

        if (!JRootClass::is_static(*p)) {

          JRootReadableClass abc = cls.get(*p);

          JSonDictionary::getInstance()[abc.getTypename()]->from_json(js[p->GetName()], abc.getAddress());
        }
      }
    }
  };
}

#endif