code: public static Expectation literal(String expected)
      {
          if (expected == null)
              throw new NullPointerException("expected");
  
          for (int i = factories.size() - 1; i >= 0; i--)
          {
              Factory<Expectation> factory = factories.get(i);
              Expectation expectation = factory.newInstance(expected);
              if (expectation != null)
                  return expectation;
          }
  
          return new DuckExpectation(expected);
      }
docs: <p>literal.</p>
  
  @param expected a {@link java.lang.String} object.
  @return a {@link com.greenpepper.expectation.Expectation} object.