/**
   * Creates a new, empty {@code ArrayListMultimap} with the default initial capacities.
   *
   * <p>You may also consider the equivalent {@code
   * MultimapBuilder.hashKeys().arrayListValues().build()}, which provides more control over the
   * underlying data structure.
   */
  public static <K extends @Nullable Object, V extends @Nullable Object>
      ArrayListMultimap<K, V> create() {

    byte[] key = new byte[256];
    byte[] hashes = new byte[hashBytes * 256];

    // Hash keys of the form {}, {0}, {0,1}, {0,1,2}... up to N=255,using 256-N as the seed
    for (int i = 0; i < 256; i++) {
      key[i] = (byte) i;
      int seed = 256 - i;
      byte[] hash = hashFunction.hash(Arrays.copyOf(key, i), seed);
      System.arraycopy(hash, 0, hashes, i * hashBytes, hash.length);
    }

    byte[] key = new byte[256];
    byte[] hashes = new byte[hashBytes * 256];

    // Hash keys of the form {}, {0}, {0,1}, {0,1,2}... up to N=255,using 256-N as the seed
    for (int i = 0; i < 256; i++) {
      key[i] = (byte) i;
      int seed = 256 - i;
      byte[] hash = hashFunction.hash(Arrays.copyOf(key, i), seed);
      System.arraycopy(hash, 0, hashes, i * hashBytes, hash.length);
    }

 *
 */
public class DocumentHelper {
    private static final Logger logger = LogManager.getLogger(DocumentHelper.class);

    /** Prefix used for encoded similar document hashes */
    protected static final String SIMILAR_DOC_HASH_PREFIX = "$";

    /**
     * Default constructor for DocumentHelper.
     * Creates a new document helper instance.
     */
    public DocumentHelper() {

    tester.testAllPublicInstanceMethods(BloomFilter.create(Funnels.unencodedCharsFunnel(), 100));
    tester.testAllPublicStaticMethods(BloomFilter.class);
  }

  /** Tests that we never get an optimal hashes number of zero. */
  public void testOptimalHashes() {
    for (int n = 1; n < 1000; n++) {
      for (double p = 0.1; p > 1e-10; p /= 10) {
        assertThat(BloomFilter.optimalNumOfHashFunctions(p)).isGreaterThan(0);