* Với request `PUT` tới `/items/{item_id}`, đọc body như JSON:
    * Kiểm tra xem nó có một thuộc tính bắt buộc kiểu  `str` là `name` không?
    * Kiểm tra xem nó có một thuộc tính bắt buộc kiểu `float` là `price` không?
    * Kiểm tra xem nó có một thuộc tính tùy chọn là `is_offer` không? Nếu có, nó phải có kiểu `bool`.
    * Tất cả những kiểm tra này cũng được áp dụng với các JSON lồng nhau.

import java.io.Serializable;
import java.util.NoSuchElementException;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * An empty contiguous set.
 *
 * @author Gregory Kick
 */
@GwtCompatible
@SuppressWarnings("rawtypes") // allow ungenerified Comparable types
final class EmptyContiguousSet<C extends Comparable> extends ContiguousSet<C> {
  EmptyContiguousSet(DiscreteDomain<C> domain) {

 * EqualsTester}. It includes an extra test against an instance of an arbitrary class without having
 * to explicitly add another equivalence group.
 *
 * @author Gregory Kick
 * @since 10.0
 */
@GwtCompatible
@NullMarked
public final class EquivalenceTester<T> {
  private static final int REPETITIONS = 3;

  private final Equivalence<? super T> equivalence;

import com.google.common.annotations.J2ktIncompatible;
import java.util.Map;

/**
 * An implementation of {@link ImmutableTable} that holds a single cell.
 *
 * @author Gregory Kick
 */
@GwtCompatible
final class SingletonImmutableTable<R, C, V> extends ImmutableTable<R, C, V> {
  final R singleRowKey;
  final C singleColumnKey;
  final V singleValue;

import com.google.common.testing.EqualsTester;
import java.util.Objects;
import org.jspecify.annotations.NullMarked;

/**
 * Tests {@link SingletonImmutableTable}.
 *
 * @author Gregory Kick
 */
@GwtCompatible
@NullMarked
public class SingletonImmutableTableTest extends AbstractImmutableTableTest {
  private final ImmutableTable<Character, Integer, String> testTable =

        TestResource resource = new TestResource("old");
        resourceManager.registerResource(resource);

        assertFalse(resource.isClosed());

        // Wait for automatic cleanup to kick in
        Thread.sleep(300);

        // Perform cleanup
        resourceManager.performCleanup();

        // Old resource should be auto-closed
        assertTrue(resource.isClosed());
    }

import org.jspecify.annotations.NullMarked;

/**
 * Implementation helper for {@link EqualsTester} and {@link EquivalenceTester} that tests for
 * equivalence classes.
 *
 * @author Gregory Kick
 */
@GwtCompatible
@NullMarked
final class RelationshipTester<T> {
  interface ItemReporter {
    String reportItem(Item<?> item);
  }

  /**

import org.jspecify.annotations.NullMarked;

/**
 * Implementation helper for {@link EqualsTester} and {@link EquivalenceTester} that tests for
 * equivalence classes.
 *
 * @author Gregory Kick
 */
@GwtCompatible
@NullMarked
final class RelationshipTester<T> {
  interface ItemReporter {
    String reportItem(Item<?> item);
  }

  /**

import java.io.Serializable;
import java.util.Collection;
import org.jspecify.annotations.Nullable;

/**
 * An implementation of {@link ContiguousSet} that contains one or more elements.
 *
 * @author Gregory Kick
 */
@GwtCompatible
@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
final class RegularContiguousSet<C extends Comparable> extends ContiguousSet<C> {
  private final Range<C> range;

     */
    public Date getLogoffTime() {
        return this.logoffTime;
    }

    /**
     * Returns the time when the user's session will be forcibly terminated.
     * @return the kick off timestamp
     */
    public Date getKickOffTime() {
        return this.kickOffTime;
    }

    /**
     * Returns the time when the user's password was last changed.