* situations, you may wish to override {@link ForwardingMultiset#elementSet} to forward to this
   * implementation or a subclass thereof.
   *
   * @since 10.0
   */
  protected class StandardElementSet extends Multisets.ElementSet<E> {
    /** Constructor for use by subclasses. */
    public StandardElementSet() {}

    @Override
    Multiset<E> multiset() {
      return ForwardingMultiset.this;
    }

 * The performance of these calls on the underlying network. If the network’s performance isn’t sufficient, you need to either improve the network or use less of it.

### EventListener

package com.google.common.graph;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.base.Supplier;
import com.google.common.collect.ForwardingSet;
import java.util.Set;

/**
 * A subclass of `ForwardingSet` that throws `IllegalStateException` on invocation of any method
 * (except `hashCode` and `equals`) if the provided `Supplier` returns false.
 */
final class InvalidatableSet<E> extends ForwardingSet<E> {

import org.jspecify.annotations.Nullable;

/**
 * A utility similar to {@link IteratorTester} for testing a {@link ListIterator} against a known
 * good reference implementation. As with {@code IteratorTester}, a concrete subclass must provide
 * target iterators on demand. It also requires three additional constructor parameters: {@code
 * elementsToInsert}, the elements to be passed to {@code set()} and {@code add()} calls; {@code

/**
 * {@link FluentFuture} that forwards all calls to a delegate.
 *
 * <h3>Extension</h3>
 *
 * If you want a class like {@code FluentFuture} but with extra methods, we recommend declaring your
 * own subclass of {@link ListenableFuture}, complete with a method like {@link #from} to adapt an
 * existing {@code ListenableFuture}, implemented atop a {@link ForwardingListenableFuture} that
 * forwards to that future and adds the desired methods.

        assertTrue(exception.getStackTrace().length > 0);
        assertNull(exception.getCause());
    }

    public void test_inheritance() {
        // Test that ResultOffsetExceededException is a subclass of FessSystemException
        ResultOffsetExceededException exception = new ResultOffsetExceededException("Test message");

        assertTrue(exception instanceof FessSystemException);

   * ForwardingNavigableMap#navigableKeySet} to forward to this implementation or a subclass
   * thereof.
   *
   * @since 12.0
   */
  protected class StandardNavigableKeySet extends Maps.NavigableKeySet<K, V> {
    /** Constructor for use by subclasses. */
    public StandardNavigableKeySet() {
      super(ForwardingNavigableMap.this);
    }
  }

  @Override

   * ForwardingNavigableMap#navigableKeySet} to forward to this implementation or a subclass
   * thereof.
   *
   * @since 12.0
   */
  protected class StandardNavigableKeySet extends Maps.NavigableKeySet<K, V> {
    /** Constructor for use by subclasses. */
    public StandardNavigableKeySet() {
      super(ForwardingNavigableMap.this);
    }
  }

  @Override

    /*
     * Yes, we sometimes set nextInKeyBucket to null, even for this "non-terminal" entry. We don't
     * do that with a plain NonTerminalImmutableMapEntry, but we do it with the BiMap-specific
     * subclass below. That's because the Entry might be non-terminal in the key bucket but terminal
     * in the value bucket (or vice versa).
     */
    private final transient @Nullable ImmutableMapEntry<K, V> nextInKeyBucket;

   *
   * <p>In many cases, you may wish to override {@link ForwardingNavigableSet#descendingSet} to
   * forward to this implementation or a subclass thereof.
   *
   * @since 12.0
   */
  protected class StandardDescendingSet extends Sets.DescendingSet<E> {
    /** Constructor for use by subclasses. */
    public StandardDescendingSet() {
      super(ForwardingNavigableSet.this);
    }
  }

  @Override