code: public final ChildSelector<T> element(QName qname, ElementConstraint...constraints) {
          ElementEqualsConstraint nameConstraint = new ElementEqualsConstraint(qname);
          return new ChildSelector<T>(getContext(), getCurrentSelector(), 
                  ElementSelector.gatherConstraints(nameConstraint, constraints));
      }
docs: Select an element with a specified <code>QName</code>.
  @param name element qname to match
  @param constraints additional constraints, if any
  @return element selector