* @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

    inverse = forward;
  }

  @Override
  protected Map<K, V> delegate() {
    return delegate;
  }

  /** Returns its input, or throws an exception if this is not a valid key. */
  @CanIgnoreReturnValue
  @ParametricNullness
  K checkKey(@ParametricNullness K key) {
    return key;
  }

  /** Returns its input, or throws an exception if this is not a valid value. */
  @CanIgnoreReturnValue

        return ComponentUtil.getRequestManager();
    }

    /**
     * Gets the current time as a Date object.
     *
     * @return The current time.
     */
    public Date getCurrentTime() {
        return new Date(getCurrentTimeAsLong());
    }

    /**
     * Gets the current time in milliseconds.
     *
     * @return The current time in milliseconds.
     */

     */
    @Override
    public boolean isConnected() {
        return this.treeConnection.isConnected();
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.SmbTreeHandle#getConfig()
     */
    @Override
    public Configuration getConfig() {
        return this.treeConnection.getConfig();
    }

    /**
     * @return the currently connected tree id
     */
    public long getTreeId() {

    @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;
    }

        remove(key);
        return true;
      }
      return false;
    }
  }

  @Override
  public boolean replace(K key, V oldValue, V newValue) {
    synchronized (lock) {
      if (oldValue.equals(get(key))) {
        alertListenerIfPresent(key, oldValue, RemovalCause.REPLACED);
        put(key, newValue);
        return true;
      }
      return false;
    }
  }

  @Override

                return false;
            }
        } else if (!first.equals(other.first)) {
            return false;
        }
        if (second == null) {
            if (other.second != null) {
                return false;
            }
        } else if (!second.equals(other.second)) {
            return false;
        }
        return true;
    }

  @Override
  public Graph<N> asGraph() {
    return new AbstractGraph<N>() {
      @Override
      public Set<N> nodes() {
        return AbstractValueGraph.this.nodes();
      }

      @Override
      public Set<EndpointPair<N>> edges() {
        return AbstractValueGraph.this.edges();
      }

      @Override
      public boolean isDirected() {
        return AbstractValueGraph.this.isDirected();
      }

                    }
                    return result;
                default:
                    return 0;
            }
        }

        public StringItem getStringPart() {
            return stringPart;
        }

        public Item getDigitPart() {
            return digitPart;
        }

        @Override
        public int getType() {
            return COMBINATION_ITEM;
        }

    @Override
    String normalizeWord(String word) {
      return Ascii.toLowerCase(word);
    }

    @Override
    String convert(CaseFormat format, String s) {
      if (format == LOWER_UNDERSCORE) {
        return s.replace('-', '_');
      }
      if (format == UPPER_UNDERSCORE) {
        return Ascii.toUpperCase(s.replace('-', '_'));
      }
      return super.convert(format, s);
    }
  },