code: public String getAttributeName() {
          if (attributeNames == null) {
             return null;
          }
          if (isMultiAttributeMode()) {
              throw new IllegalStateException("Request contains more than one attribute (attrs = " +
                                              "" + attributeNames + "). Use getAttributeNames() instead.");
          }
          return attributeNames.get(0);
      }
docs: Get a single attribute name. If this request was initialized with more than one attribute this
  methods throws an exception.
  @return the attribute's name or null
  @throws IllegalStateException if this request was initialized with more than one attribute.