code: private boolean isNullSetting(boolean makeDest,MappingType mtd,MappingType mts,StringBuilder result){
  		if( 	makeDest  
  			&& (mtd == ALL_FIELDS||mtd == ONLY_VALUED_FIELDS) 
  			&&	mts == ONLY_NULL_FIELDS){
  			result.append("   "+stringOfSetDestination+"(null);"+newLine);
  			return true;
  		}
  		return false;
  	}
docs: if it is a null setting returns the null mapping
  @param makeDest true if destination is a new instance
  @param mtd mapping type of destination
  @param mts mapping type of source
  @param result StringBuilder used for mapping
  @return true if operation is a null setting, false otherwise