* @param string the string to test and possibly return
   * @return {@code string} if it is not null; {@code ""} otherwise
   */
  static String nullToEmpty(@Nullable String string) {
    return (string == null) ? "" : string;
  }

  /**
   * Returns the string if it is not empty, or a null string otherwise.
   *
   * @param string the string to test and possibly return
   * @return {@code string} if it is not empty; {@code null} otherwise

            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        @SuppressWarnings("unchecked")
        final Pair<T1, T2> other = (Pair<T1, T2>) obj;
        if (first == null) {
            if (other.first != null) {
                return false;
            }

				// return a different error in such a scenario.
				if u.Credentials.Status == auth.AccountOff {
					return nil, errAccessKeyDisabled
				}
				return nil, errInvalidAccessKeyID
			}
			cred := u.Credentials
			// Expired credentials return error.
			if cred.IsTemp() && cred.IsExpired() {
				return nil, errInvalidAccessKeyID
			}
			return []byte(cred.SecretKey), nil

      return ImmutableSet.copyOf(elements);
    }
  }

  public static class ImmutableSetUnsizedBuilderGenerator extends TestStringSetGenerator {
    @Override
    protected Set<String> create(String[] elements) {
      ImmutableSet.Builder<String> builder = ImmutableSet.builder();
      for (String e : elements) {
        builder.add(e);
      }
      return builder.build();
    }
  }

					c.connChange.L.Unlock()
					return
				}
			case <-ctx.Done():
				c.connChange.L.Unlock()
				return
			}
		}
	}()

	for {
		select {
		case <-ctx.Done():
			return context.Cause(ctx)
		case newState := <-changed:
			if newState == StateConnected {
				return nil
			}
		}
	}
}

/*

        case COMPRESSION_NONE:
            return "None";
        case COMPRESSION_LZ77:
            return "LZ77";
        case COMPRESSION_LZ77_HUFFMAN:
            return "LZ77+Huffman";
        case COMPRESSION_LZNT1:
            return "LZNT1";
        case COMPRESSION_PATTERN_V1:
            return "Pattern_V1";
        default:
            return "Unknown(0x" + Integer.toHexString(algorithm) + ")";
        }

    this.values = new Object[expectedSize];

    return expectedSize;
  }

  @SuppressWarnings("unchecked")
  @VisibleForTesting
  @Nullable Map<K, V> delegateOrNull() {
    if (table instanceof Map) {
      return (Map<K, V>) table;
    }
    return null;
  }

  Map<K, V> createHashFloodingResistantDelegate(int tableSize) {
    return new LinkedHashMap<>(tableSize, 1.0f);
  }

        case CrudMode.CREATE:
            return OptionalEntity.of(new RelatedQuery()).map(entity -> {
                entity.setCreatedBy(username);
                entity.setCreatedTime(currentTime);
                return entity;
            });
        case CrudMode.EDIT:
            if (form instanceof EditForm) {

            return false;
        }
        if (exception == null) {
            if (other.exception != null) {
                return false;
            }
        } else if (!exception.getClass().equals(other.exception.getClass())) {
            return false;
        }
        if (requestType != other.requestType) {
            return false;
        } else {
            return source.equals(other.source);

    @Override
    protected Float doForward(String value) {
      return Float.valueOf(value);
    }

    @Override
    protected String doBackward(Float value) {
      return value.toString();
    }

    @Override
    public String toString() {
      return "Floats.stringConverter()";
    }

    private Object readResolve() {
      return INSTANCE;
    }