code: public static FieldAnnotation fromVisitedField(PreorderVisitor visitor) {
          return new FieldAnnotation(visitor.getDottedClassName(), visitor.getFieldName(), visitor.getFieldSig(),
                  visitor.getFieldIsStatic());
      }
docs: Factory method. Class name, field name, and field signatures are taken
  from the given visitor, which is visiting the field.
  
  @param visitor
  the visitor which is visiting the field
  @return the FieldAnnotation object