*
 * @author Kevin Bourrillion
 * @since 11.0
 */
@Immutable
public interface HashFunction {
  /**
   * Begins a new hash code computation by returning an initialized, stateful {@code Hasher}
   * instance that is ready to receive data. Example:
   *
   * {@snippet :
   * HashFunction hf = Hashing.md5();
   * HashCode hc = hf.newHasher()
   *     .putLong(id)
   *     .putBoolean(isActive)

 *
 * @author Kevin Bourrillion
 * @since 11.0
 */
@Immutable
public interface HashFunction {
  /**
   * Begins a new hash code computation by returning an initialized, stateful {@code Hasher}
   * instance that is ready to receive data. Example:
   *
   * {@snippet :
   * HashFunction hf = Hashing.md5();
   * HashCode hc = hf.newHasher()
   *     .putLong(id)
   *     .putBoolean(isActive)

    assertHashByteBufferMatchesBytes(hashFunction);
    assertHashByteBufferExhaustsBuffer(hashFunction);
    assertHashByteBufferPreservesByteOrder(hashFunction);
    assertHasherByteBufferPreservesByteOrder(hashFunction);
  }

  static void assertHashByteBufferMatchesBytes(HashFunction hashFunction) {
    Random rng = new Random(0L);

   *
   * @since 19.0
   */
  public static HashFunction concatenating(Iterable<HashFunction> hashFunctions) {
    checkNotNull(hashFunctions);
    // We can't use Iterables.toArray() here because there's no hash->collect dependency
    List<HashFunction> list = new ArrayList<>();
    for (HashFunction hashFunction : hashFunctions) {
      list.add(hashFunction);
    }

    SHA_256("SHA-256", Hashing.sha256()),
    SHA_384("SHA-384", Hashing.sha384()),
    SHA_512("SHA-512", Hashing.sha512());

    private final String algorithmName;
    private final HashFunction hashFn;

    Algorithm(String algorithmName, HashFunction hashFn) {
      this.algorithmName = algorithmName;
      this.hashFn = hashFn;
    }

    MessageDigest getMessageDigest() {
      try {

    SHA_256("SHA-256", Hashing.sha256()),
    SHA_384("SHA-384", Hashing.sha384()),
    SHA_512("SHA-512", Hashing.sha512());

    private final String algorithmName;
    private final HashFunction hashFn;

    Algorithm(String algorithmName, HashFunction hashFn) {
      this.algorithmName = algorithmName;
      this.hashFn = hashFn;
    }

    MessageDigest getMessageDigest() {
      try {

      imports = "com.google.common.io.Files")
  public
  static HashCode hash(File file, HashFunction hashFunction) throws IOException {
    return asByteSource(file).hash(hashFunction);
  }

  /**
   * Fully maps a file read-only in to memory as per {@link
   * FileChannel#map(java.nio.channels.FileChannel.MapMode, long, long)}.
   *
   * <p>Files are mapped from offset 0 to its length.

/**
 * Unit test for FarmHashFingerprint64.
 *
 * @author Kyle Maddison
 * @author Geoff Pike
 */
@NullUnmarked
public class FarmHashFingerprint64Test extends TestCase {

  private static final HashFunction HASH_FN = Hashing.farmHashFingerprint64();

  // If this test fails, all bets are off
  @SuppressWarnings("InlineMeInliner") // String.repeat unavailable under Java 8
  public void testReallySimpleFingerprints() {

          .put(3, 0x9fcc3c3fde4d5ff7L)
          .put(2, 0x090966a836e5fa4bL)
          .put(1, 0x8199675ecaa6fe64L)
          .put(0, 0x23ad7c904aa665e3L)
          .build();
  private static final HashFunction HASH_FN = Hashing.fingerprint2011();

  // If this test fails, all bets are off
  @SuppressWarnings("InlineMeInliner") // String.repeat unavailable under Java 8
  public void testReallySimpleFingerprints() {

import org.opensearch.index.query.QueryBuilders;
import org.opensearch.search.SearchHit;
import org.opensearch.search.SearchHits;
import org.opensearch.search.sort.SortBuilder;

import com.google.common.hash.HashFunction;
import com.google.common.hash.Hashing;

import jakarta.annotation.Resource;

/**
 * Abstract base class for crawler services that interact with OpenSearch.
 *
 * @author shinsuke
 *
 */