private final ReentrantLock lock;

  /**
   * The guards associated with this monitor that currently have waiters ({@code waiterCount > 0}).
   * A linked list threaded through the Guard.next field.
   */
  @GuardedBy("lock")
  private @Nullable Guard activeGuards = null;

  /**
   * Creates a monitor with a non-fair (but fast) ordering policy. Equivalent to {@code
   * Monitor(false)}.
   */

        ContainsPatternPredicate that = (ContainsPatternPredicate) obj;

        // Pattern uses Object (identity) equality, so we have to reach
        // inside to compare individual fields.
        return Objects.equals(pattern.pattern(), that.pattern.pattern())
            && pattern.flags() == that.pattern.flags();
      }
      return false;
    }

    @Override

* `response_model_exclude_none=True`

详见 [Pydantic 文档](https://docs.pydantic.dev/1.10/usage/exporting_models/#modeldict)中对 `exclude_defaults` 和 `exclude_none` 的说明。

///

#### 默认字段有实际值的数据 { #data-with-values-for-fields-with-defaults }

但是，如果你的数据在具有默认值的模型字段中有实际的值，例如 ID 为 `bar` 的项：

```Python hl_lines="3  5"
{
    "name": "Bar",
    "description": "The bartenders",
    "price": 62,
    "tax": 20.2
}
```

      size += list.size();
    }

    return new ImmutableListMultimap<>(builder.buildOrThrow(), size);
  }

  /**
   * An instance created in {@link #readObject} to be returned from {@link #readResolve}. This field
   * is used only by those methods, and it is never set in a "normal" instance.
   *
   * <p>For more background, see {@code ConcurrentHashMultiset.deserializationReplacement}.
   */

func TestFields(t *testing.T) {
	for _, tt := range fieldstests {
		b := []byte(tt.s)
		a := Fields(b)

		// Appending to the results should not change future results.
		var x []byte
		for _, v := range a {
			x = append(v, 'z')
		}

		result := sliceOfString(a)
		if !slices.Equal(result, tt.a) {
			t.Errorf("Fields(%q) = %v; want %v", tt.s, a, tt.a)
			continue
		}

  private class Itr implements Iterator<E> {
    /** Index of element to be returned by next, or a negative number if no such. */
    private int nextIndex;

    /**
     * nextItem holds on to item fields because once we claim that an element exists in hasNext(),
     * we must return it in the following next() call even if it was in the process of being removed
     * when hasNext() was called.
     */

	}

	if createdByRel, ok := userSchema.Relationships.Relations["CreatedBy"]; ok {
		if createdByRel.FieldSchema != userSchema {
			t.Fatalf("expects same field schema, but got new %p, old %p", createdByRel.FieldSchema, userSchema)
		}
	} else {
		t.Fatalf("expects created by relations, but not found")
	}
}

func TestEmbeddedHas(t *testing.T) {
	type Toy struct {

**Spoiler alert**: the tutorial - user guide includes:

* Declaration of **parameters** from other different places as: **headers**, **cookies**, **form fields** and **files**.
* How to set **validation constraints** as `maximum_length` or `regex`.

若想看包含更多功能的完整範例，請參考 <a href="https://fastapi.tiangolo.com/zh-hant/tutorial/">Tutorial - User Guide</a>。

**劇透警告**：教學 - 使用者指南包含：

* 來自不同來源的**參數**宣告：例如 **headers**、**cookies**、**form fields** 和 **files**。
* 如何設定**驗證限制**，如 `maximum_length` 或 `regex`。
* 一個非常強大且易用的 **<dfn title="也稱為：components、resources、providers、services、injectables">依賴注入</dfn>** 系統。
* 安全與驗證，包含支援 **OAuth2** 搭配 **JWT tokens** 與 **HTTP Basic** 驗證。

**Spoiler alert**: the tutorial - user guide includes:

* Declaration of **parameters** from other different places as: **headers**, **cookies**, **form fields** and **files**.
* How to set **validation constraints** as `maximum_length` or `regex`.