import net.sourceforge.ondex.core.ONDEXConcept;
import net.sourceforge.ondex.core.ONDEXGraph;
import net.sourceforge.ondex.core.ONDEXGraphMetaData;
import net.sourceforge.ondex.core.ONDEXRelation;
import net.sourceforge.ondex.core.RelationType;
import net.sourceforge.ondex.core.util.BitSetFunctions;
import net.sourceforge.ondex.exception.type.AccessDeniedException;
import net.sourceforge.ondex.exception.type.NullValueException;

/**
 * This class is the core of the ONDEX backend and contains all Concepts and
 * Relations as well as additional data like DataSources or ConceptClasses in
 * the ONDEXGraphMetaData.
 * 
