private TimeoutManager() {
    }

    /**
     * Returns the instance for the singleton.
     *
     * @return the instance for the singleton
     */
    public static TimeoutManager getInstance() {
        return instance;
    }

    /**
     * Starts the process.
     */
    public synchronized void start() {
        if (thread == null) {

     * @param index The index name.
     * @return This builder instance.
     */
    public PopularWordsRequestBuilder setIndex(final String index) {
        request.setIndex(index);
        return this;
    }

    /**
     * Sets the size of results for the request.
     * @param size The size.
     * @return This builder instance.
     */
    public PopularWordsRequestBuilder setSize(final int size) {

  /**
   * Returns a representation of {@code a} as an instance of type {@code B}. If {@code a} cannot be
   * converted, an unchecked exception (such as {@link IllegalArgumentException}) should be thrown.
   *
   * @param a the instance to convert; will never be null
   * @return the converted instance; <b>must not</b> be null
   */
  @ForOverride
  protected abstract B doForward(A a);

import org.apache.maven.toolchain.model.ToolchainModel;

/**
 * Internal toolchain factory, to prepare toolchains instances.
 *
 * @since 2.0.9
 * @deprecated Use {@link org.apache.maven.api.services.ToolchainFactory} instead.
 */
@Deprecated(since = "4.0.0")
public interface ToolchainFactory {
    /**
     * Create instance of toolchain.
     **/

    /**
     * Creates a new empty DataStoreParams instance.
     * Initializes the internal parameter map with a ParamMap wrapper.
     */
    public DataStoreParams() {
        params = new ParamMap<>(new HashMap<>());
    }

    /**
     * Creates a new DataStoreParams instance with a copy of the provided parameters.
     * This protected constructor is used for creating new instances from existing parameter maps.
     *

    }

    /**
     * Retrieves the current thread-local instance of the UrlQueueService.
     *
     * @return the UrlQueueService instance associated with the current thread.
     */
    public static UrlQueueService<UrlQueue<?>> getUrlQueueService() {
        return URL_QUEUE_SERVICE_THREAD_LOCAL.get();
    }

    /**
     * Sets the UrlQueueService instance to the thread-local variable.

  }

  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.
    return Iterables.get(instances, (generateInt() - 1) % instances.size());
  }

     */
    boolean embedded();

    /**
     * Creates a new Builder instance for constructing a Maven ParserRequest.
     *
     * @param args the command-line arguments
     * @param messageBuilderFactory the factory for creating message builders
     * @return a new Builder instance
     */
    @Nonnull

          // TODO: Fix tests not to call this directly and make it throw an error.
          return null;
        }
      };

  /**
   * Returns a builder for creating simple, fast escapers. A builder instance can be reused and each
   * escaper that is created will be a snapshot of the current builder state. Builders are not
   * thread safe.
   *
   * <p>The initial state of the builder is such that:
   *
   * <ul>

    if match is found, the toolchain instance is made available to other Maven plugins.</p>
    <p>With {@code jdk} toolchain, for example, instead of being stuck with the JDK used to run Maven, all plugins can use
    the same other JDK instance without hardcoding absolute paths into the {@code pom.xml}
    and without configuring every plugin that require path to JDK tools.</p>