/**
 * Base class for implementing services that can handle {@link #doStart} and {@link #doStop}
 * requests, responding to them with {@link #notifyStarted()} and {@link #notifyStopped()}
 * callbacks. Its subclasses must manage threads manually; consider {@link
 * AbstractExecutionThreadService} if you need only a single execution thread.
 *
 * @author Jesse Wilson
 * @author Luke Sandberg
 * @since 1.0
 */
@GwtIncompatible

 * doEquivalent and doHash methods to indicate that the parameter cannot be null.
 */
@SuppressWarnings("UngroupedOverloads")
public abstract class Equivalence<T> {
  /** Constructor for use by subclasses. */
  protected Equivalence() {}

  /**
   * Returns {@code true} if the given objects are considered equivalent.
   *
   * <p>This method describes an <i>equivalence relation</i> on object references, meaning that for

import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import org.jspecify.annotations.Nullable;

/**
 * An abstract {@code ScheduledExecutorService} that allows subclasses to {@linkplain
 * #wrapTask(Callable) wrap} tasks before they are submitted to the underlying executor.
 *
 * <p>Note that task wrapping may occur even if the task is never executed.
 *
 * @author Luke Sandberg
 */

 * @author Sven Mawson
 * @since 15.0
 */
@GwtCompatible
@SuppressWarnings("EscapedEntity") // We do mean for the user to see "<" etc.
public abstract class CharEscaper extends Escaper {
  /** Constructor for use by subclasses. */
  protected CharEscaper() {}

  /**
   * Returns the escaped form of a given literal string.
   *
   * @param string the literal string to be escaped
   * @return the escaped form of {@code string}

 * @since 10.0 (<a href="https://github.com/google/guava/wiki/Compatibility">mostly
 *     source-compatible</a> since 9.0)
 */
@GwtCompatible
public abstract class Ticker {
  /** Constructor for use by subclasses. */
  protected Ticker() {}

  /** Returns the number of nanoseconds elapsed since this ticker's fixed point of reference. */
  public abstract long read();

  /**

 *
 * @since {@code com.google.guava:failureaccess:1.0}, which was added as a dependency of Guava in
 *     Guava 27.0
 */
public abstract class InternalFutureFailureAccess {
  /** Constructor for use by subclasses. */
  protected InternalFutureFailureAccess() {}

  /**
   * Usually returns {@code null} but, if this {@code Future} has failed, may <i>optionally</i>

        return process(target);
    }

    /**
     * Basic processing method that other process methods delegate to.
     * Default implementation returns the target unchanged.
     * Subclasses should override this method to implement specific processing logic.
     *
     * @param target the document data to process
     * @return the processed document data
     */

/**
 * Tests that all package-private {@code writeReplace} methods are overridden in any existing
 * subclasses. Without such overrides, optimizers might put a {@code writeReplace}-containing class
 * and its subclass in different packages, causing the serialization system to fail to invoke {@code
 * writeReplace} when serializing an instance of the subclass. For an example of this problem, see
 * b/310253115.
 */
@NullUnmarked

 * implementations.
 *
 * <p>This base implementation has no key or value pointers, so instances of ImmutableMapEntry (but
 * not its subclasses) can be reused when copied from one ImmutableMap to another.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible // unnecessary
class ImmutableMapEntry<K, V> extends SimpleImmutableEntry<K, V> {
  /**

   * implemented in terms of that method (though they will likely be overridden by subclasses for
   * performance reasons).) This means that a call to this method have can different behavior in GWT
   * and non-GWT environments UNLESS subclasses are careful to always override all methods
   * implemented in terms of sortedDelegate (except comparator()).
   */