code: public AbstractPrintQuery addAttribute(final String... _attrNames)
          throws EFapsException
      {
          final Type type = getMainType();
          if (type != null) {
              for (final String attrName : _attrNames) {
                  final Attribute attr = type.getAttribute(attrName);
                  if (attr == null) {
                      final AttributeSet set = AttributeSet.find(type.getName(), attrName);
                      if (set != null) {
                          addAttributeSet(set);
                      }
                  } else {
                      addAttribute(attr);
                  }
              }
          }
          return this;
      }
docs: Add an attribute to the PrintQuery. It is used to get editable values
  from the eFaps DataBase.
  
  @param _attrNames Name of the Attribute to add
  @return this PrintQuery
  @throws EFapsException on error