name: Feature request
about: Suggest an idea
title: ''
labels: enhancement
assignees: ''

---

Start by telling us what problem you’re trying to solve. Often a solution already exists!

package com.google.common.util.concurrent;

import com.google.common.annotations.GwtCompatible;
import java.util.concurrent.ScheduledFuture;
import org.jspecify.annotations.Nullable;

/**
 * Helper interface to implement both {@link ListenableFuture} and {@link ScheduledFuture}.
 *
 * @author Anthony Zana
 * @since 15.0
 */
@GwtCompatible
public interface ListenableScheduledFuture<V extends @Nullable Object>

   *
   * <p>Although all tasks are immediately executed in the thread that submitted the task, this
   * {@code ExecutorService} imposes a small locking overhead on each task submission in order to
   * implement shutdown and termination behavior.
   *
   * <p>Because of the nature of single-thread execution, the methods {@code scheduleAtFixedRate}
   * and {@code scheduleWithFixedDelay} are not supported by this class and will throw an

 * instance for non-daemon threads.
 *
 * The task runner is also responsible for releasing held threads when the library is unloaded.
 * This is for the benefit of container environments that implement code unloading.
 *
 * Most applications should share a process-wide [TaskRunner] and use queues for per-client work.
 */
class TaskRunner(
  val backend: Backend,
  internal val logger: Logger = TaskRunner.logger,

 * {@link ValueGraph}, and {@link Network}):
 *
 * {@snippet :
 * someGraphAlgorithm(startNode, graph);
 * }
 *
 * This works because those types each implement {@code PredecessorsFunction}. It will also work
 * with any other implementation of this interface.
 *
 * <p>If you have your own graph implementation based around a custom node type {@code MyNode},

 * {@link CrawlerContainer}. It also provides a convenient method for
 * registering the extractor with the {@link ExtractorFactory}.
 * </p>
 *
 * <p>
 * Subclasses should implement the actual extraction logic in their own
 * methods, leveraging the helper methods provided by this abstract class.
 * </p>
 *
 */
public abstract class AbstractExtractor implements Extractor {

    int i = 0;
    for (Object e : elements) {
      array[i++] = (Character) e;
    }
    return create(array);
  }

  /**
   * Creates a new collection containing the given elements; implement this method instead of {@link
   * #create(Object...)}.
   */
  protected abstract List<Character> create(Character[] elements);

  @Override
  public Character[] createArray(int length) {

    int i = 0;
    for (Object e : elements) {
      array[i++] = (UnhashableObject) e;
    }
    return create(array);
  }

  /**
   * Creates a new collection containing the given elements; implement this method instead of {@link
   * #create(Object...)}.
   */
  protected abstract T create(UnhashableObject[] elements);

  @Override
  public UnhashableObject[] createArray(int length) {

    int i = 0;
    for (Object e : elements) {
      array[i++] = (String) e;
    }
    return create(array);
  }

  /**
   * Creates a new collection containing the given elements; implement this method instead of {@link
   * #create(Object...)}.
   */
  protected abstract List<String> create(String[] elements);

  @Override
  public String[] createArray(int length) {
    return new String[length];

 * thought of as overkill; however, it's difficult to determine which proper subset of this massive
 * set would be sufficient to expose any possible bug. Brute force is simpler.
 *
 * <p>To use this class the concrete subclass must implement the {@link
 * IteratorTester#newTargetIterator()} method. This is because it's impossible to test an Iterator
 * without changing its state, so the tester needs a steady supply of fresh Iterators.
 *