if (host.getValue2().equalsIgnoreCase(headerValue)) {
                    return func.apply(host.getValue3());
                }
            }
            return defaultValue;
        }).orElse(defaultValue);
    }

    public String[] getVirtualHostPaths() {
        return stream(ComponentUtil.getFessConfig().getVirtualHosts())

    throw new UnsupportedOperationException();
  }

  private <T> T pickInstance(T[] instances, T defaultValue) {
    return pickInstance(Arrays.asList(instances), defaultValue);
  }

  private <T> T pickInstance(Collection<T> instances, T defaultValue) {
    if (instances.isEmpty()) {
      return defaultValue;
    }
    // generateInt() is 1-based.

   * position}th position or {@code defaultValue} otherwise.
   *
   * @param position position of the element to return
   * @param defaultValue the default value to return if the iterator is empty or if {@code position}
   *     is greater than the number of elements remaining in {@code iterator}
   * @return the element at the specified position in {@code iterator} or {@code defaultValue} if

            if (appendValue != null) {
                buf.append(appendValue);
            }
            cmdList.add(buf.toString());
        } else if (defaultValue != null) {
            cmdList.add("-D" + name + "=" + defaultValue);
        }
    }

    protected void addFessConfigProperties(final List<String> cmdList) {

  /**
   * Returns the contained instance if it is present; {@code defaultValue} otherwise. If no default
   * value should be required because the instance is known to be present, use {@link #get()}
   * instead. For a default value of {@code null}, use {@link #orNull}.
   *
   * <p>Note about generics: The signature {@code public T or(T defaultValue)} is overly

   * position}th position or {@code defaultValue} otherwise.
   *
   * @param position position of the element to return
   * @param defaultValue the default value to return if the iterator is empty or if {@code position}
   *     is greater than the number of elements remaining in {@code iterator}
   * @return the element at the specified position in {@code iterator} or {@code defaultValue} if

    }

    @Override
    public Path getPath() {
        return artifact.getPath();
    }

    @Override
    public String getProperty(String key, String defaultValue) {
        return artifact.getProperty(key, defaultValue);
    }

    @Override
    public Map<String, String> getProperties() {
        return artifact.getProperties();
    }

    public String getMessage() {

  }

  @Override
  public boolean isPresent() {
    return true;
  }

  @Override
  public T get() {
    return reference;
  }

  @Override
  public T or(T defaultValue) {
    checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
    return reference;
  }

  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    checkNotNull(secondChoice);

  }

  @Override
  public boolean isPresent() {
    return true;
  }

  @Override
  public T get() {
    return reference;
  }

  @Override
  public T or(T defaultValue) {
    checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
    return reference;
  }

  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    checkNotNull(secondChoice);

            }
            return null;
        }

        protected String getProperty(final String key, final String defaultValue) {
            return ComponentUtil.getSystemProperties().getProperty(key, defaultValue);
        }

        protected String getResourcePath(final String path) {
            final File file = ResourceUtil.getResourceAsFileNoException(path);