* "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
public abstract class ImmutableMultiset<E> extends ImmutableCollection<E> implements Multiset<E> {

  /**

 * This exception is typically thrown during authentication or user lookup operations
 * when the specified user does not exist in the system.
 */
public class FessUserNotFoundException extends FessSystemException {

    /** Serial version UID for serialization compatibility */
    private static final long serialVersionUID = 1L;

    /**
     * Constructs a new FessUserNotFoundException with the specified username.
     *

    }

    public boolean hasRole(final String role) {
        return stream(user.getRoleNames()).get(stream -> stream.anyMatch(s -> s.equals(role)));
    }

    public boolean hasRoles(final String[] acceptedRoles) {
        return stream(user.getRoleNames())
                .get(stream -> stream.anyMatch(s1 -> stream(acceptedRoles).get(s3 -> s3.anyMatch(s2 -> s2.equals(s1)))));
    }

import com.google.common.base.Preconditions;
import java.util.Spliterator;

/**
 * Implementation of {@link ImmutableList} with exactly one element.
 *
 * @author Hayward Chan
 */
@GwtCompatible
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class SingletonImmutableList<E> extends ImmutableList<E> {

  final transient E element;

  SingletonImmutableList(E element) {

import com.google.common.annotations.J2ktIncompatible;
import org.jspecify.annotations.Nullable;

/**
 * A descending wrapper around an {@code ImmutableSortedMultiset}
 *
 * @author Louis Wasserman
 */
@SuppressWarnings("serial") // uses writeReplace, not default serialization
@GwtIncompatible
final class DescendingImmutableSortedMultiset<E> extends ImmutableSortedMultiset<E> {
  private final transient ImmutableSortedMultiset<E> forward;

 * has not actually been put in the {@code BloomFilter}.
 *
 * <p>Bloom filters are serializable. They also support a more compact serial representation via the
 * {@link #writeTo} and {@link #readFrom} methods. Both serialized forms will continue to be
 * supported by future versions of this library. However, serial forms generated by newer versions
 * of the code may not be readable by older versions of the code (e.g., a serialized Bloom filter

import com.google.common.annotations.VisibleForTesting;
import org.jspecify.annotations.Nullable;

/**
 * Bimap with zero or more mappings.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class RegularImmutableBiMap<K, V> extends ImmutableBiMap<K, V> {
  static final RegularImmutableBiMap<Object, Object> EMPTY = new RegularImmutableBiMap<>();

import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link ImmutableMultiset} with zero or more elements.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class RegularImmutableMultiset<E> extends ImmutableMultiset<E> {
  static final RegularImmutableMultiset<Object> EMPTY =

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

/**
 * An immutable sorted multiset with one or more distinct elements.
 *
 * @author Louis Wasserman
 */
@SuppressWarnings("serial") // uses writeReplace, not default serialization
@GwtIncompatible
final class RegularImmutableSortedMultiset<E> extends ImmutableSortedMultiset<E> {
  private static final long[] zeroCumulativeCounts = {0};

import java.util.function.Predicate;
import org.jspecify.annotations.Nullable;

/**
 * GWT emulated version of {@link ImmutableCollection}.
 *
 * @author Jesse Wilson
 */
@SuppressWarnings("serial") // we're overriding default serialization
public abstract class ImmutableCollection<E> extends AbstractCollection<E> implements Serializable {
  static final int SPLITERATOR_CHARACTERISTICS =