K k = (K) key;
        return function.apply(k);
      } else {
        return defaultValue;
      }
    }

    @Override
    public @Nullable V remove(@Nullable Object key) {
      if (backingSet().remove(key)) {
        @SuppressWarnings("unchecked") // unsafe, but Javadoc warns about it
        K k = (K) key;
        return function.apply(k);
      } else {
        return null;
      }

public class RepositoriesSetupPlugin implements Plugin<Project> {

    private static final Pattern LUCENE_SNAPSHOT_REGEX = Pattern.compile("\\w+-snapshot-([a-z0-9]+)");

    @Override
    public void apply(Project project) {
        configureRepositories(project);
    }

    /**
     * Adds repositories used by ES projects and dependencies
     */
    public static void configureRepositories(Project project) {

 *
 * Reducing the number of reports also makes it easier to find the important ones when analysing a failed build in
 * TeamCity.
 */
val testFilesCleanup = project.extensions.create<TestFileCleanUpExtension>("testFilesCleanup").apply {
    reportOnly.convention(false)
}

// TODO:isolated:incremental the service won't track up-to-date projects (project configuration skipped) that still run tests

    DelayingIdentityLoader(CountDownLatch delayLatch) {
      this.delayLatch = delayLatch;
    }

    @CanIgnoreReturnValue // Sure, why not?
    @Override
    public T apply(T key) {
      awaitUninterruptibly(delayLatch);
      return key;
    }
  }

  /*
   * TODO(cpovirk): eliminate duplication between these tests and those in LegacyMapMakerTests and
   * anywhere else
   */

 * <p>
 * This plugin will add the plugin-metadata and properties files for each
 * dependency to the test source set.
 */
public class TestWithDependenciesPlugin implements Plugin<Project> {
    @Override
    public void apply(final Project project) {
        ExtraPropertiesExtension extraProperties = project.getExtensions().getExtraProperties();
        if (extraProperties.has("isEclipse") && Boolean.valueOf(extraProperties.get("isEclipse").toString())) {

     * un-deprecated because Java callers can't chain when assigning Kotlin vals. (The getter remains
     * deprecated).
     */
    fun setLevel(level: Level) =
      apply {
        this.level = level
      }

    @JvmName("-deprecated_level")
    @Deprecated(
      message = "moved to var",
      replaceWith = ReplaceWith(expression = "level"),

  companion object {
    private lateinit var logger: Logger

    private val SSLSession.masterSecret: SecretKey?
      get() =
        javaClass
          .getDeclaredField("masterSecret")
          .apply {
            isAccessible = true
          }.get(this) as? SecretKey

    val randomRegex = "\"random\"\\s+:\\s+\"([^\"]+)\"".toRegex()

    fun register() {

  private var authenticator = JavaNetAuthenticator()
  private val fakeDns = FakeDns()
  private val recordingAuthenticator = RecordingAuthenticator()
  private val factory =
    TestValueFactory()
      .apply {
        dns = fakeDns
      }

  @BeforeEach
  fun setup() {
    Authenticator.setDefault(recordingAuthenticator)
  }

  @AfterEach
  fun tearDown() {
    Authenticator.setDefault(null)

  private final TearDownStack stack = new TearDownStack();

  @Override
  protected void setUp() throws Exception {
    super.setUp();

    handler = new TestLogHandler();

    // You could also apply it higher up the Logger hierarchy than this
    ExampleClassUnderTest.logger.addHandler(handler);

    ExampleClassUnderTest.logger.setUseParentHandlers(false); // optional

    stack.addTearDown(
        () -> {

mvn clean package                     # Build
mvn install                           # Install to local Maven repo
mvn formatter:format                  # Format code
mvn license:format                    # Apply license headers
mvn verify                            # Generate coverage report
```

## Code Conventions

### Class Structure

- **Utility classes**: `abstract` class + `protected` constructor