* situations, you may wish to override {@link SortedMultiset#elementSet} to forward to this
   * implementation or a subclass thereof.
   *
   * @since 15.0
   */
  protected class StandardElementSet extends SortedMultisets.NavigableElementSet<E> {
    /** Constructor for use by subclasses. */
    public StandardElementSet() {
      super(ForwardingSortedMultiset.this);
    }
  }

  @Override

   * ForwardingSortedMap}. In many cases, you may wish to override {@link
   * ForwardingSortedMap#keySet} to forward to this implementation or a subclass thereof.
   *
   * @since 15.0
   */
  protected class StandardKeySet extends Maps.SortedKeySet<K, V> {
    /** Constructor for use by subclasses. */
    public StandardKeySet() {
      super(ForwardingSortedMap.this);
    }
  }

import com.google.common.collect.ImmutableMap;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.concurrent.ExecutionException;

/**
 * A cache which forwards all its method calls to another cache. Subclasses should override one or
 * more methods to modify the behavior of the backing cache as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

    }
  }

  /** Constructor for use by subclasses. */
  protected AbstractIdleService() {}

  /** Start the service. */
  protected abstract void startUp() throws Exception;

  /** Stop the service. */
  protected abstract void shutDown() throws Exception;

  /**
   * Returns the {@link Executor} that will be used to run this service. Subclasses may override

import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;
import org.jspecify.annotations.Nullable;

/**
 * A cache which forwards all its method calls to another cache. Subclasses should override one or
 * more methods to modify the behavior of the backing cache as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * @author Charles Fry

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.List;
import org.jspecify.annotations.Nullable;

/**
 * A list multimap which forwards all its method calls to another list multimap. Subclasses should
 * override one or more methods to modify the behavior of the backing multimap as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

import java.util.Comparator;
import java.util.SortedSet;
import org.jspecify.annotations.Nullable;

/**
 * A sorted set multimap which forwards all its method calls to another sorted set multimap.
 * Subclasses should override one or more methods to modify the behavior of the backing multimap as
 * desired per the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

import java.util.concurrent.Callable;
import org.jspecify.annotations.Nullable;

/**
 * A listening executor service which forwards all its method calls to another listening executor
 * service. Subclasses should override one or more methods to modify the behavior of the backing
 * executor service as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

   * ForwardingSortedMap}. In many cases, you may wish to override {@link
   * ForwardingSortedMap#keySet} to forward to this implementation or a subclass thereof.
   *
   * @since 15.0
   */
  protected class StandardKeySet extends Maps.SortedKeySet<K, V> {
    /** Constructor for use by subclasses. */
    public StandardKeySet() {
      super(ForwardingSortedMap.this);
    }
  }

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.ListIterator;
import org.jspecify.annotations.Nullable;

/**
 * A list iterator which forwards all its method calls to another list iterator. Subclasses should
 * override one or more methods to modify the behavior of the backing iterator as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *