JDATABASE::JDBReader< T > Struct Template Reference

Auxiliary class to read ROOT object from database. More...

#include <JDBReader.hh>

Inheritance diagram for JDATABASE::JDBReader< T >:

Public Types
typedef T	data_type

Public Member Functions
	JDBReader ()
	Default constructor. More...
const T &	operator() (ResultSet &rs)
	Read ROOT object from result set. More...

Static Public Member Functions
static void	reset ()
	Reset internal lookup table. More...
static void	set (const std::vector< Selector > &selection)
	Set default value corresponding to given selection. More...
static data_type &	getInstance ()
	Get unique instance of template class. More...

Private Attributes
T	object
	internal value More...
T	value
	default value More...
JROOT::JRootReader	reader
std::vector < JROOT::JRootReadableClass >	buffer

Detailed Description

template<class T>
struct JDATABASE::JDBReader< T >

Auxiliary class to read ROOT object from database.

The names of the table columns are one-to-one mapped to the names of the data members of the corresponding data structure using the ROOT dictionary.
The method JDBReader::set can be used to a priori assign default values to those data members that are defined by the selector used in the query.
Note that the list of column names associated to the template parameter is considered to be permanent.
If not, the static method JDBReader::reset should be called before the next read operation.

Definition at line 91 of file JDBReader.hh.

Member Typedef Documentation

template<class T>

typedef T JLANG::JSingleton< T >::data_type

inherited

Definition at line 20 of file JSingleton.hh.

Constructor & Destructor Documentation

template<class T>

JDATABASE::JDBReader< T >::JDBReader ( )

inline

Default constructor.

Definition at line 97 of file JDBReader.hh.

                :
      object(),
      reader(JLANG::null, JLANG::JEquationParameters(), JDBDictionary::getInstance())
    {}

Member Function Documentation

template<class T>

static void JDATABASE::JDBReader< T >::reset ( )

inlinestatic

Reset internal lookup table.

Definition at line 106 of file JDBReader.hh.

    {
      JDBReader<T>::getInstance().buffer.clear();

      JDBReader<T>::getInstance().value = T();
    }

template<class T>

static void JDATABASE::JDBReader< T >::set ( const std::vector< Selector > &  selection )

inlinestatic

Set default value corresponding to given selection.

Parameters

selection

selection

Definition at line 119 of file JDBReader.hh.

    {
      selection >> JDBReader<T>::getInstance().value;
    }

template<class T>

const T& JDATABASE::JDBReader< T >::operator() ( ResultSet &  rs )

inline

Read ROOT object from result set.

Parameters

rs	result set

Returns

object

Definition at line 131 of file JDBReader.hh.

    {
      using namespace std;
      using namespace JPP;

      object = value;

      if (buffer.empty()) {

        JRootReadableClass cls(object);

        for (size_t i = 0; i != rs.FieldCount(); ++i) {

          string parameter = rs.FieldName(i);

          for (string::const_iterator i = SPECIAL_CHARACTERS.begin(); i != SPECIAL_CHARACTERS.end(); ++i) {
            for (string::size_type pos; (pos = parameter.find(*i)) != string::npos; ) {
              parameter.erase(pos);
            }
          }
        
          buffer.push_back(cls.find(parameter.c_str()));
        }
      }

      for (unsigned int i = 0; i != rs.FieldCount(); ++i) {

        if (buffer[i].is_valid()) {     

          JRedirectString redirect(reader, rs.GetString(i));
      
          reader.getObject(buffer[i]);
        }
      }

      return object;
    }

template<class T>

static data_type& JLANG::JSingleton< T >::getInstance ( )

inlinestaticinherited

Get unique instance of template class.

Returns

object

Definition at line 27 of file JSingleton.hh.

    {
      static data_type value;

      return value;
    }

Member Data Documentation

template<class T>

T JDATABASE::JDBReader< T >::object

private

internal value

Definition at line 170 of file JDBReader.hh.

template<class T>

T JDATABASE::JDBReader< T >::value

private

default value

Definition at line 171 of file JDBReader.hh.

template<class T>

JROOT::JRootReader JDATABASE::JDBReader< T >::reader

private

Definition at line 172 of file JDBReader.hh.

template<class T>

std::vector<JROOT::JRootReadableClass> JDATABASE::JDBReader< T >::buffer

private

Definition at line 174 of file JDBReader.hh.

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The documentation for this struct was generated from the following file:

• JDBReader.hh