/** String constant representing boolean true value. */
    public static final String TRUE = "true";

    /** String constant representing boolean false value. */
    public static final String FALSE = "false";

    /** Boolean constant representing true value. */
    public static final Boolean T = true;

    /** Boolean constant representing false value. */

      Class<T> enumClass) {
    synchronized (enumConstantCache) {
      Map<String, WeakReference<? extends Enum<?>>> constants = enumConstantCache.get(enumClass);
      if (constants == null) {
        constants = populateCache(enumClass);
      }
      return constants;
    }
  }

  /**
   * Returns a serializable converter that converts between strings and {@code enum} values of type

  }

  static final class ConstantWeigher implements Weigher<Object, Object> {
    private final int constant;

    ConstantWeigher(int constant) {
      this.constant = constant;
    }

    @Override
    public int weigh(Object key, Object value) {
      return constant;
    }
  }

  static final class IntKeyWeigher implements Weigher<Integer, Object> {
    @Override

    /** Log type constant for zero-click search aggregation. */
    public static final String LOG_TYPE_SEARCH_ZEROCLICK = "search_zeroclick_agg";

    /** Log type constant for click logs. */
    public static final String LOG_TYPE_CLICK = "click";

    /** Log type constant for click count aggregation. */
    public static final String LOG_TYPE_CLICK_COUNT = "click_count_agg";

    /** Log type constant for favorite logs. */

    assertEquals("correct", f.apply(new Object()));
    assertEquals("correct", f.apply(null));

    Function<@Nullable Object, @Nullable String> g = Functions.constant(null);
    assertEquals(null, g.apply(2));
    assertEquals(null, g.apply(null));

    new EqualsTester()
        .addEqualityGroup(f, Functions.constant("correct"))

    assertEquals("correct", f.apply(new Object()));
    assertEquals("correct", f.apply(null));

    Function<@Nullable Object, @Nullable String> g = Functions.constant(null);
    assertEquals(null, g.apply(2));
    assertEquals(null, g.apply(null));

    new EqualsTester()
        .addEqualityGroup(f, Functions.constant("correct"))

     * type.
     *
     * In practice, we are very unlikely to see `null`: The `WeakReference` to the enum constant
     * won't be cleared as long as the enum constant is referenced somewhere, and the enum constant
     * is referenced somewhere for as long as the enum class is loaded. *Maybe in theory* the enum

    for (MediaType constant : getConstants()) {
      assertSame(constant, MediaType.parse(constant.toString()));
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  public void testCreate_useConstants() throws Exception {
    for (MediaType constant : getConstants()) {
      assertSame(
          constant,
          MediaType.create(constant.type(), constant.subtype())

    new EqualsTester()
        .addEqualityGroup(
            Suppliers.compose(Functions.constant(1), Suppliers.ofInstance("foo")),
            Suppliers.compose(Functions.constant(1), Suppliers.ofInstance("foo")))
        .addEqualityGroup(Suppliers.compose(Functions.constant(2), Suppliers.ofInstance("foo")))
        .addEqualityGroup(Suppliers.compose(Functions.constant(1), Suppliers.ofInstance("bar")))
        .testEquals();
  }

   * (The inverse of this will be a horizontal transformation.)
   */
  public static LinearTransformation vertical(double x) {
    checkArgument(isFinite(x));
    return new VerticalLinearTransformation(x);
  }

  /**
   * Builds an instance representing a horizontal transformation with a constant value of {@code y}.