Jinzhu <******@****.***> 1762092514 +0800

И тогда вам не придётся задумываться о названиях вроде `Optional` и `Union`. 😎

#### Generic-типы { #generic-types }

Типы, которые принимают параметры типов в квадратных скобках, называются **Generic-типами** или **Generics**, например:

//// tab | Python 3.10+

Вы можете использовать те же встроенные типы как generics (с квадратными скобками и типами внутри):

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

		},
		{
			Name:     "generics-nested-joins-2",
			Manager:  GetUser("generics-nested-joins-manager-2", Config{Company: true, NamedPet: true}),
			NamedPet: &Pet{Name: "generics-nested-joins-namepet-2", Toy: Toy{Name: "generics-nested-joins-namepet-toy-2"}},
		},
	}

	ctx := context.Background()
	db := gorm.G[User](DB)

And then you won't have to worry about names like `Optional` and `Union`. 😎

#### Generic types { #generic-types }

These types that take type parameters in square brackets are called **Generic types** or **Generics**, for example:

//// tab | Python 3.10+

You can use the same builtin types as generics (with square brackets and types inside):

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

Und dann müssen Sie sich nicht mehr um Namen wie `Optional` und `Union` kümmern. 😎

#### Generische Typen { #generic-types }

Diese Typen, die Typ-Parameter in eckigen Klammern akzeptieren, werden **generische Typen** oder **Generics** genannt.

//// tab | Python 3.10+

Sie können die eingebauten Typen als Generics verwenden (mit eckigen Klammern und Typen darin):

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

- **Type safety** - Extensive use of generics and null-safe operations throughout the API
- **Resource management** - Proper handling of resources with utilities like `CloseableUtil` and `DisposableUtil`

### Key Architectural Patterns
- **Factory Pattern** - `BeanDescFactory` for creating bean descriptors, `ParameterizedClassDescFactory` for generic type handling

   * use the {@code ArrayList} {@linkplain ArrayList#ArrayList() constructor} directly, taking
   * advantage of <a
   * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
   * syntax</a>.
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call

    // We assume that all defaults are generics-safe, even if they aren't,
    // we take the risk.
    @SuppressWarnings("unchecked")
    T defaultValue = (T) defaults.getInstance(type.getRawType());
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // All arbitrary instances are generics-safe
    T arbitrary = (T) ArbitraryInstances.get(type.getRawType());

   * value should be required because the instance is known to be present, use {@link #get()}
   * instead. For a default value of {@code null}, use {@link #orNull}.
   *
   * <p>Note about generics: The signature {@code public T or(T defaultValue)} is overly
   * restrictive. However, the ideal signature, {@code public <S super T> S or(S)}, is not legal

    // We assume that all defaults are generics-safe, even if they aren't,
    // we take the risk.
    @SuppressWarnings("unchecked")
    T defaultValue = (T) defaults.getInstance(type.getRawType());
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // All arbitrary instances are generics-safe
    T arbitrary = (T) ArbitraryInstances.get(type.getRawType());