qqxhb <******@****.***> 1774092864 +0800

  }

  private static class StringWrapper {
    private final String value;

    StringWrapper(String value) {
      this.value = value;
    }
  }

  @GwtIncompatible // J2CL generics problem
  public void testAndThen() {
    Converter<StringWrapper, String> first =
        new Converter<StringWrapper, String>() {
          @Override
          protected String doForward(StringWrapper object) {

    Class<? super T> rawType = type.getRawType();
    @SuppressWarnings("unchecked") // Assume all default values are generics safe.
    T defaultValue = (T) defaultValues.getInstance(rawType);
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // ArbitraryInstances always returns generics-safe dummies.
    T value = (T) ArbitraryInstances.get(rawType);
    if (value != null) {
      return value;

   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated. Instead,
   * use the {@code HashMap} constructor directly, taking advantage of <a
   * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
   * syntax</a>.
   *
   * @return a new, empty {@code HashMap}
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call

   *
   * <p>The type specification is {@code <E extends Comparable>}, instead of the more specific
   * {@code <E extends Comparable<? super E>>}, to support classes defined without generics.
   */
  @SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
  public static <E extends Comparable> TreeMultiset<E> create() {
    return new TreeMultiset<>(Ordering.natural());
  }

  /**

   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated. Instead,
   * use the {@code HashMap} constructor directly, taking advantage of <a
   * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
   * syntax</a>.
   *
   * @return a new, empty {@code HashMap}
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call

        checkNotNull(entry.getValue());
      }
      @SuppressWarnings({"unchecked", "rawtypes"})
      // immutable collections are safe for covariant casts
      // and getting the generics right for EnumMap is difficult to impossible
      ImmutableMap<K, V> result = ImmutableEnumMap.asImmutable(new EnumMap(enumMap));
      return result;
    }

    int size = map.size();
    switch (size) {

```python
from typing import Any


def some_function(data: Any):
    print(data)
```

### 泛型（Generic types） { #generic-types }

有些型別可以在方括號中接收「型別參數」，以定義其內部元素的型別，例如「字串的 list」可以宣告為 `list[str]`。

這些能接收型別參數的型別稱為「泛型（Generic types）」或「Generics」。

你可以將相同的內建型別用作泛型（使用方括號並在裡面放型別）：

* `list`
* `tuple`
* `set`
* `dict`

#### List { #list }

```python
from typing import Any


def some_function(data: Any):
    print(data)
```

### 泛型类型 { #generic-types }

有些类型可以在方括号中接收“类型参数”（type parameters），用于声明其内部值的类型。比如“字符串列表”可以写为 `list[str]`。

这些能接收类型参数的类型称为“泛型类型”（Generic types）或“泛型”（Generics）。

你可以把相同的内建类型作为泛型使用（带方括号和内部类型）：

* `list`
* `tuple`
* `set`
* `dict`

#### 列表 { #list }

      return getDone(future);
    }
  }

  private static class MyException extends Exception {}

  // Class hierarchy for generics sanity checks
  private static class Foo {}

  private static class FooChild extends Foo {}

  private static class Bar {}

  private static class BarChild extends Bar {}