}

  /**
   * Returns a serializable converter object that converts between strings and integers using {@link
   * Integer#decode} and {@link Integer#toString()}. The returned converter throws {@link
   * NumberFormatException} if the input string is invalid.
   *
   * <p><b>Warning:</b> please see {@link Integer#decode} to understand exactly how strings are

      // TODO(lowasser): could be potentially optimized, but only with
      // extensive testing
      try {
        return Double.parseDouble(string);
      } catch (NumberFormatException e) {
        // Double.parseDouble has changed specs several times, so fall through
        // gracefully
      }
    }
    return null;
  }

                            "Invalid threads value: '" + threadConfiguration + "'. Value must be positive.");
                }
                return threads;
            }
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException("Invalid threads value: '" + threadConfiguration
                    + "'. Supported are int and float values ending with C.");
        }
    }

                return Integer.valueOf(from);
              }
            });

    Iterator<Integer> resultIterator = result.iterator();
    resultIterator.next();

    assertThrows(NumberFormatException.class, () -> resultIterator.next());
  }

  public void testNullFriendlyTransform() {
    List<@Nullable Integer> input = asList(1, 2, null, 3);
    Iterable<String> result =
        Iterables.transform(

              @Override
              public Integer apply(String from) {
                return Integer.valueOf(from);
              }
            });

    result.next();
    assertThrows(NumberFormatException.class, () -> result.next());
  }

  public void testNullFriendlyTransform() {
    Iterator<@Nullable Integer> input = Arrays.<@Nullable Integer>asList(1, 2, null, 3).iterator();
    Iterator<String> result =

        val portString = input.canonicalize(pos = pos, limit = limit, encodeSet = "")
        val i = portString.toInt()
        if (i in 1..65535) i else -1
      } catch (_: NumberFormatException) {
        -1 // Invalid port.
      }
  }

  companion object {
    /** Returns 80 if `scheme.equals("http")`, 443 if `scheme.equals("https")` and -1 otherwise. */
    @JvmStatic