stackWithLastReturnedElementAtTop = null;
    }

    @Override
    public boolean hasNext() {
      return !nextElements.isEmpty();
    }

    @Override
    public boolean hasPrevious() {
      return !previousElements.isEmpty();
    }

    @Override
    public E next() {
      return transferElement(nextElements, previousElements);
    }

    @Override

                .stream()
                .map(MavenProject::getVersion)
                .collect(Collectors.collectingAndThen(Collectors.toList(), Collections::unmodifiableList));
        if (!versions.isEmpty()) {
            return versions;
        }
        return getAllProjects()
                .getOrDefault(artifact.getGroupId(), Collections.emptyMap())

  }

  static String formatCompact4Digits(double value) {
    return String.format(Locale.ROOT, "%.4g", value);
  }

  static boolean stringIsNullOrEmpty(@Nullable String string) {
    return string == null || string.isEmpty();
  }

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

    CacheBuilderSpec spec = new CacheBuilderSpec(cacheBuilderSpecification);
    if (!cacheBuilderSpecification.isEmpty()) {
      for (String keyValuePair : KEYS_SPLITTER.split(cacheBuilderSpecification)) {
        List<String> keyAndValue = ImmutableList.copyOf(KEY_VALUE_SPLITTER.split(keyValuePair));
        checkArgument(!keyAndValue.isEmpty(), "blank key-value pair");
        checkArgument(
            keyAndValue.size() <= 2,

    CacheBuilderSpec spec = new CacheBuilderSpec(cacheBuilderSpecification);
    if (!cacheBuilderSpecification.isEmpty()) {
      for (String keyValuePair : KEYS_SPLITTER.split(cacheBuilderSpecification)) {
        List<String> keyAndValue = ImmutableList.copyOf(KEY_VALUE_SPLITTER.split(keyValuePair));
        checkArgument(!keyAndValue.isEmpty(), "blank key-value pair");
        checkArgument(
            keyAndValue.size() <= 2,

      assertFalse(testInstance.containsValue("blah"));
    }
  }

  public void testIsEmpty() {
    for (ImmutableTable<Character, Integer, String> testInstance : getTestInstances()) {
      assertFalse(testInstance.isEmpty());
    }
  }

  public void testForCells() {
    assertTrue(RegularImmutableTable.forCells(CELLS) instanceof DenseImmutableTable<?, ?, ?>);
    assertTrue(
        RegularImmutableTable.forCells(

    assertEmpty(result);
    assertEquals(0, result.size());
  }

  @CollectionSize.Require(absent = ZERO)
  public void testGetNonEmpty() {
    Collection<V> result = multimap().get(k0());
    assertFalse(result.isEmpty());
    assertContentsAnyOrder(result, v0());
  }

  @CollectionSize.Require(SEVERAL)
  public void testGetMultiple() {
    resetContainer(mapEntry(k0(), v0()), mapEntry(k0(), v1()), mapEntry(k0(), v2()));

                    keysByAlgo.put(key.getKeyType(), key);
                }

                KerberosKey serverKey = keysByAlgo.get(encType.getValue().intValue());
                if (keysByAlgo.isEmpty() || serverKey == null) {
                    throw new PACDecodingException("Kerberos key not found for eType " + encType.getValue());
                }

                try {

        String base = basedir.getAbsolutePath();
        if (path.startsWith(base)) {
            path = chopLeadingFileSeparator(path.substring(base.length()));
        }

        if (path.isEmpty()) {
            path = ".";
        }

        if (!new File(path).isAbsolute()) {
            path = path.replace('\\', '/');
        }

        return path;
    }

        // Execute
        CorsHandlerFactory factory = new CorsHandlerFactory();

        // Verify
        assertNotNull(factory);
        assertNotNull(factory.handerMap);
        assertTrue(factory.handerMap.isEmpty());
    }

    // Test implementation of CorsHandler for testing purposes
    private static class TestCorsHandler extends CorsHandler {
        private final String name;